TEST: Steinberg U44 - 22

Steinberg, one of the big German names in recording, brings another desktop interface to the market with the UR 22 and its larger sibling, the UR 44. These units aim to hold their own in the fiercely competitive segment up to around 300 euros. To avoid being left behind in the wake of other competitors, special features in terms of sound and build quality are expected nowadays. Even though manufacturing in China is almost unavoidable in this price range, Steinberg will still try to incorporate as many trademarks of a German company into the manufacturing process as possible.

The areas of preamp sound quality and product build still offer a large surface area to score points against the competition. Additionally, portability, appropriate connection peripherals, and possibly a crisp appearance contribute to users leaning towards one product or another for their budget production. Both products are primarily aimed at musicians, producers, or sound engineers looking for a small, mobile interface that not only convinces with very good measured values but can also quickly disappear into the nearest briefcase when transport is needed.

With the UR series, Steinberg has set out to fulfill all the above-mentioned points and possibly add an extra scoop in one area or another. The UR 22 and UR 44 products are available for testing, which follow the same conceptual design but differ significantly in terms of connectivity options. However, the UR 44 also increases in price by over 100 percent at around 300 euros compared to its little brother at around 140 euros. Let's see which one best covers which areas of application.

Construction

Both products in the UR series share a uniform appearance. The first thing that stands out is the massive steel housing, which leaves an extremely sturdy impression. Scratches will probably not be completely avoidable, but compared to their plastic colleagues, the UR housings will definitely shine with increased longevity. Both products rest on four soft rubber feet, which offer very good stability on smooth surfaces, although they were not glued on too accurately in terms of right angles. Admittedly, a very marginal defect. Since small products are often stolen by unsavory individuals, there is a Kensington lock security opening on the back of both housings.

With dimensions of 158 mm x 45 mm x 158 mm (UR 22) and 252 mm x 47 mm x 158 mm (UR 44) (W x H x D), both products take up comparatively little space on the desktop and are also so flat in terms of height that they fit under the base of a standard monitor. The weight of just under one kilogram (UR 22) and 1.6 kilograms (UR 44) respectively also supports the mobile application area. In terms of system requirements, both products prove to be extremely modest. According to factory specifications, in the PC area, Windows XP with just 2 GB RAM is sufficient, while on OSX even the 10.5.8 variant passes. As always with all specifications, especially in the RAM area, double or more is welcome for smooth operation.

ASIO is used as the driver, which ensures comparatively short latency with high stability despite the high sampling rates of up to 192 kHz and a word width of 24 bits. In terms of power supply, the UR 22 is satisfied with the PC's internal USB port, while the UR 44 requires the supplied power adapter. This means the UR 22 is tidier with fewer cables but is dependent on the DAW used. As expected, both products come with a Steinberg program as recording software, in this case, Cubase AI. To be immediately available for all platforms, Steinberg has built a so-called CC switch on the back of the UR 44, which ensures that when activated, Apple products, for example under iOS, immediately recognize the product as an interface. However, activation prevents hardware support under Cubase.

Visually, one immediately recognizes the affiliation to the same product family. In addition to the same controls and conceptual orientation, the same preamps were also used. As with the larger brother UR 824, the so-called D-Pre preamps from Yamaha are used, which are supposed to generate better values in the signal flow through the use of twice the number of transistors. In terms of inputs, the UR 22 has 2 combo sockets (UR 44 4 combo sockets), all of which can be supplied with 48V phantom power if needed. The UR 44 is also equipped for the operation of high-impedance instruments such as an electric bass on inputs 1 and 2, while the remaining inputs can handle a line level if desired. The UR 44 also has 2 additional line inputs on the rear of the housing.

The UR 44 can output 2 different mixes from the device via 2 separate line outputs. For this purpose, the UR 22 has a very useful mix control, which allows a continuous crossfade between the input and DAW signal. While the UR 44 has 2 separately controllable headphone outputs, the UR 22 has to make do with just one output. To avoid all synchronization problems, both products have both MIDI In and MIDI Out. Another bonus of the UR 44 is the DSP-supported effects, which enable latency-free monitoring of the effect sections Guitar Amp Classics, REV-X Reverb, Sweet Spot Morphing Channel Strip, and in the computer area, a phase switch per channel and a high-pass filter.

In terms of displays, both devices are rather sparse. There is only a peak display per channel along with 48V power supply. Ultimately, personal tastes in this regard will vary between "completely sufficient" to "insufficient," so this point should be considered neutral.

Practice

In practice, the first thing that stands out is the very high gain reserves of the preamps, which with -67.5 dB can ensure adequate level adjustment even for very weak signals. Another highlight must be the neutral sound of the interfaces, which could process all connected sound sources flawlessly, free from noise or other extraneous sounds. As expected, the preamps never work at their limit even with weak signals due to their high gain reserves and thus have sufficient headroom with any signal flow.

In terms of resolution and impulse response, both devices do a very good job, especially when considering the mobile recording application area. No real weaknesses could be identified in any area, leaving an all-around successful overall impression that will cause some furrowed brows among the competition.

Expanding on the Technical Aspects

The Steinberg UR series utilizes Class-A D-PRE microphone preamps, which are known for their transparent and detailed sound. These preamps offer a wide gain range, allowing for clean amplification of both very weak and strong input signals. The use of inverted Darlington circuits in the preamp design contributes to the low distortion and balanced frequency response.

Both the UR 22 and UR 44 support high-resolution audio with sampling rates up to 192 kHz and 24-bit depth. This high-resolution capability allows for capturing subtle nuances in recordings, especially beneficial for acoustic instruments and vocal performances where preserving the natural timbre is crucial.

The UR 44's DSP mixer deserves special mention. It allows for zero-latency monitoring with effects, which is particularly useful during tracking sessions. The included effects, such as the REV-X reverb, are of studio quality and can be applied during recording without taxing the computer's CPU.

Integration with DAW Software

While Cubase AI is included with both interfaces, the UR series is designed to work seamlessly with most popular DAWs. The driver's stability and low-latency performance are particularly noteworthy, allowing for real-time monitoring even in complex project setups.

For Cubase users, the UR series offers additional integration features. The "Basic FX Suite" plug-ins can be used directly within Cubase projects, providing a consistent workflow from recording through to mixing. The Sweet Spot Morphing Channel Strip, in particular, is a versatile tool that combines compression, EQ, and saturation in an easy-to-use interface.

Mobile Recording Capabilities

The UR 22's bus-powered operation makes it an excellent choice for field recording and mobile setups. Its compact size and rugged construction allow it to withstand the rigors of on-location recording. The ability to record at high sample rates while powered solely by a laptop's USB port is a significant advantage for documentarians and live event recordists.

The UR 44, while requiring external power, offers more flexibility for small ensemble recordings. Its additional inputs and outputs make it suitable for recording drum kits or small bands, where multiple microphones are needed simultaneously.

Comparison with Competitors

In the competitive field of budget audio interfaces, the Steinberg UR series holds its own against popular alternatives like the Focusrite Scarlett series or the PreSonus AudioBox range. The UR preamps are often praised for their cleaner and more transparent sound compared to some competitors in the same price range.

The build quality of the UR series is notably superior to many plastic-housed interfaces in this category. The all-metal construction not only provides better durability but also offers improved shielding against electromagnetic interference, which can be crucial in less-than-ideal recording environments.

Long-term Reliability and Support

Steinberg's reputation for long-term driver support is a significant factor to consider. Many users report years of trouble-free operation with their UR interfaces, with driver updates ensuring compatibility with new operating systems and DAW versions.

The company's heritage in audio software development also means that the integration between hardware and software is particularly well-thought-out. This synergy often results in a more stable and efficient workflow compared to some third-party interfaces.

Applications in Various Music Genres

For electronic music producers, the UR series offers low-latency monitoring essential for working with software synthesizers and drum machines. The direct monitoring feature allows for immediate response when playing virtual instruments, crucial for capturing performative elements in electronic music production.

In rock and pop recording scenarios, the UR 44's multiple inputs shine. Recording a vocalist while simultaneously capturing a guitar and bass direct input is easily achievable. The onboard DSP effects allow for adding compression and reverb to the monitor mix without introducing latency, helping performers feel more comfortable during tracking.

For classical and jazz recordings, where capturing the natural dynamics of performances is crucial, the clean gain structure of the D-PRE preamps proves invaluable. The high headroom ensures that even sudden peaks in acoustic instruments are captured without distortion.

Future-Proofing and Expandability

While the UR series doesn't offer direct expandability in terms of additional inputs, its MIDI I/O allows for integration with external MIDI interfaces or controllers. This feature enables users to expand their setup with MIDI-equipped synthesizers, drum machines, or control surfaces without needing to upgrade the audio interface itself.

The high sample rate support also future-proofs these interfaces to some extent. As higher resolution audio becomes more common in professional workflows, the UR series is well-positioned to meet these demands without requiring immediate replacement.

Conclusion

The Steinberg UR 22 and UR 44 represent solid choices in the competitive budget audio interface market. They offer a balanced combination of sound quality, build durability, and useful features that cater well to their target audience of home studio owners, mobile recordists, and budget-conscious professionals.

The UR 22 stands out as an excellent portable solution, ideal for singer-songwriters, podcasters, or anyone needing a simple, high-quality recording setup. Its bus-powered operation and compact form factor make it a go-to choice for on-the-go recording.

The UR 44, with its expanded I/O and DSP capabilities, offers more flexibility for small project studios or bands looking to record multiple sources simultaneously. The addition of MIDI I/O on both models also increases their versatility, allowing for easy integration with a wide range of music production setups.

While they may not offer the most extensive feature set in their class, the UR series compensates with reliability, sound quality, and a no-nonsense approach to audio recording. The robust build quality suggests these interfaces are built to last, potentially offering better value in the long run compared to some more feature-laden but less durable alternatives.

For those invested in the Steinberg ecosystem, particularly Cubase users, the integration benefits make these interfaces especially attractive. However, their broad compatibility ensures they're a viable option regardless of the user's preferred DAW.

In summary, the Steinberg UR 22 and UR 44 offer a compelling package for those seeking quality audio interfaces on a budget. They manage to strike a balance between affordability and professional-grade features, making them worthy contenders in the crowded entry-level audio interface market.

TEST: SPL Vitalizer MK3-T

 Nearly every sound engineer is familiar with the problem. Due to the incredibly high number of plugins and tracks, limited only by CPU performance and SSD access speed in DAWs, the risk of different signals overlapping and thus canceling or masking each other increases immensely. To counteract this, SPL from Niederkrüchten, Germany, has launched the third version of the SPL Vitalizer MK3-T, developed and manufactured in Germany, which aims to bring more transparency to the mix through a combination of psychoacoustics and audiometry.

The Concept of the SPL Vitalizer MK3-T

One of the crucial elements of the patented Vitalizer circuit is the so-called demasking of signals that are overlaid by other signal components. The Vitalizer correlates the perception timing of a frequency significantly with its volume. Through a wafer-thin temporal offset of loud frequencies, quieter sound nuances are revealed that were previously hidden by overlapping elements and thus made audible. The system is based on the non-linear sensitivity of human hearing developed in 1930 through the so-called Fletcher-Munson curves. These curves, nowadays refined by the ISO 226:2003 standard, illustrate the constant perception of loudness across the frequency spectrum. This results in a constant sound pressure level when a listener is played pure, even tones. According to the manufacturer, the newly created signal sounds more lively, has more details, and possesses higher loudness.

The Construction of the SPL Vitalizer MK3-T

The SPL Vitalizer Mk3-T presents itself with a massive, black anodized aluminum front panel 4 mm thick. The housing impresses with high-quality, solid steel construction and an optically attractive black powder coating, which replaces the gold lacquer used on previous models. Due to a higher internal audio voltage of +/-18 V, the sound is said to have improved even further compared to versions 1 and 2. Despite its 1U design and moderate depth of 300 mm, the product weighs in at nearly 6.1 kg, which reflects, among other things, the solid construction of the product.

A total of 5 controls are responsible for adjusting the de-masking effect:

Drive: The control of the filter network is regulated by the Drive knob, with the control range between -20 dB and +6 dB. In the center position (0 dB), the drive level corresponds exactly to the input level.

OVL: The OVL LED signals potential overdriving of both the input stages and internal processes. The OVL LED lights up 3 dB before overdriving to ensure that the Vitalizer always produces an optimal sound.

Bass Sound: The Bass Sound control allows the selection between two bass timbres.

Soft: By moving the Bass Sound control from the center position (0) to the left, the bass range becomes soft and warm, which is referred to as "Soft."

Tight: Moving the Bass Sound control from the center position (0) to the right results in a dry and percussive bass range, referred to as "Tight." The square representation of the scaling points on the right side symbolizes this contoured, tight bass sound.

Bass Comp: The Stereo Vitalizer Mk3-T is equipped with a spartan "one-knob" compressor for the bass processing path, which leaves the original bass content untouched. Attack, Release, and Threshold are preset. By increasing the Bass Comp value, both the compression ratio and the threshold are adjusted. The compressor works with a soft-knee control characteristic to sound as inconspicuous as possible. The Gain Reduction LED "GR" indicates when the compressor is active.

Mid-Hi Tune: The Mid-Hi Tune control sets the onset frequency or lower cutoff frequency, above which frequencies are boosted with the selected Process value, or below which frequencies are attenuated. The control range of the Mid-Hi Tune knob extends from 1.1 kHz at the right stop to 22 kHz at the left stop. A Sovtek 12AX7 dual-triode tube in the filter path creates a mixing ratio between the original signal and the filter output. The tube adds its typical overtone characteristics and gives the "Mid-Hi Tune" signal a softer sound signature.

Process: The Process control adjusts the intensity of Bass and Mid-Hi Tune in relation to the original signal and performs attenuation of dominant mid-frequencies.

For additional sound processing, the following controls are available:

LC-EQ: The LC-EQ is a mid-high tone processing stage, built around a passive coil-capacitor network (LC). The LC-EQ increases presence and definition in the midrange, especially for typical mid-range instruments such as voices. The frequency is adjustable between approximately 2 kHz (Low) at the left stop and approximately 20 kHz (High) at the right stop. Coils are known for their pleasant sound image in filter circuits. In the 1960s, coil filters were often used, which were later frequently replaced by RC filters (resistor-capacitor network) due to the high price.

Intensity: The Intensity control determines the level of the LC-EQ. As intensity increases, the amplification of the set high and overtones increases. At the same time, the perception timing is shifted so that quiet high-frequency components are not masked by loud ones. This improves speech intelligibility and clarity and increases the brilliance of any audio signal without sounding harsh.

Stereo Expander: The Stereo Expander widens the stereo base width and improves the spatial impression by simulating a decentralized localization of the sound source outside the speaker plane. The Sovtek 12AX7 dual-triode tube is also used in the Stereo Expander, mixing the right and left channels. The tube adds its tube-typical harmonic spectrum to the stereo signal, consisting mainly of even overtones. In addition to widening the stereo image, the tube is said to enable greater depth layering, clearer drawing of reverb spaces, and a softening of the high-frequency range.

The Vitalizer Mk3-T is activated by the On switch, which lights up when activated. In bypass mode, the switch does not light up. A flashing switch signals the "Warm-Up" mode, in which the tubes are brought to the optimal operating temperature.

The Rear Panel of the SPL Vitalizer MK3-T

All inputs and outputs of the Vitalizer Mk3-T feature Neutrik XLR sockets with gold-plated contacts as well as Neutrik TRS sockets. Both the XLR and jack sockets are connected in parallel, and the signal transmission is electronically balanced with a nominal level of +6 dBu. On the output side, two signals are provided per output, meaning that the processed signal can be routed to two different devices. If the inputs are double-assigned, the two input signals are mixed.

To prevent ground loops, the Vitalizer MK3-T has a separate ground-lift switch. Finally, on the left side of the housing, there is a mains selector switch that allows voltage selection between 230 volts and 115 volts, and an IEC socket with fuse access.

The SPL Vitalizer MK3-T in Practice

As expected, the application area of the SPL Vitalizer MK3-T is the stereo sum or, as an insider tip, a corresponding bus where the danger of masking is always present. In my opinion, choir tracks would be the first choice here, as high soprano passages in female vocals can be very dominant depending on the frequency and quickly lead to an uneven sound image. If you combat this problem with the corresponding automation, the choir quickly sounds unbalanced, as in the Hollywood comedy Sister Act during the first choir rehearsal.

After processing the first sound files, I inevitably felt reminded of a loudness circuit on a very high-quality stereo system in the result. The SPL Vitalizer MK3-T provides a real enrichment of the signal, especially in the deep bass range as well as in the very fine highs, which of course inevitably goes hand in hand with a slight lowering of the mids. However, the sonic result is far from as "blunt" as a simple bass and treble boost using a shelving filter; you can clearly hear that the algorithm attaches itself to different instruments. You can notice it very nicely in the high range, for example, how the hi-hat in the drums gains significantly more presence without sounding obtrusive.

The SPL Vitalizer MK3-T can particularly show its strengths when it comes to refining inferior or muffled-sounding source material and giving it a significantly more pleasant touch. For example, the SPL Vitalizer MK3-T would be a very good tool for remastering old recordings that may have been rotting on some tapes in archives for ages, just waiting to be re-released.

In summary, one must say that the SPL is a very good tool, especially for mastering and subgroup areas, which can intervene in the sound event with very fine accents, but also brashly if needed, to give the source material a higher-quality finish.

Expanding on the Technical Aspects

The SPL Vitalizer MK3-T employs several sophisticated circuit designs to achieve its unique sound-shaping capabilities. One of the key elements is the use of a hybrid analog-tube circuit. The incorporation of the Sovtek 12AX7 dual-triode tube in both the Mid-Hi Tune and Stereo Expander sections adds a subtle layer of harmonic richness to the processed signal. This tube imparts a slight coloration that many engineers find pleasing, especially when dealing with digital sources that may sound somewhat sterile or lacking in depth.

The Bass Sound control deserves special attention for its innovative approach to low-frequency management. Unlike traditional bass boost circuits that simply increase gain at a fixed frequency, the Vitalizer's bass processing is more intelligent. The "Soft" setting provides a gentle, warm boost that enhances the fundamental frequencies of bass instruments without muddying the mix. On the other hand, the "Tight" setting focuses on the upper harmonics of bass sounds, adding definition and punch without excessive low-end buildup. This dual-mode bass enhancement allows engineers to tailor the low end to suit different genres and mixing situations.

The LC-EQ section is another standout feature that sets the Vitalizer apart from typical equalizers. By utilizing a passive inductor-capacitor network, this stage imparts a musical quality to the midrange and high frequencies that is difficult to achieve with active op-amp based circuits. The use of inductors in audio circuits has largely fallen out of favor due to cost and potential for interference, but when implemented correctly, as in the Vitalizer, they can provide a smooth, natural-sounding boost that enhances clarity without harshness.

Application in Various Mixing Scenarios

While the Vitalizer MK3-T excels in mastering applications, its versatility extends to various mixing scenarios. For instance, when working with dense rock mixes, the device can help carve out space for each instrument. The Mid-Hi Tune control, in particular, can be invaluable for bringing out the attack of guitars or the breathiness of vocals without resorting to excessive EQ boosts that might lead to harshness.

In electronic music production, the Stereo Expander can add width and depth to synthesizer pads and effects, creating a more immersive soundstage. The Bass Comp feature is especially useful in this genre, allowing for tighter, more controlled low end that translates well to club sound systems.

For acoustic and jazz recordings, the Vitalizer's subtle enhancement capabilities shine. The tube-based circuitry can add a touch of warmth and dimensionality that complements the natural timbres of acoustic instruments. The LC-EQ, when used judiciously, can bring out the air and intimacy of such recordings without sounding artificial.

Comparison with Software Alternatives

In the age of digital audio workstations and plugin processors, hardware units like the SPL Vitalizer MK3-T face stiff competition from software emulations and digital processors. However, many engineers still prefer the tactile experience and unique sonic character of hardware. The Vitalizer's analog circuitry, especially its tube stages, imparts a subtle but noticeable depth and dimension that is challenging to replicate exactly in the digital domain.

That being said, software alternatives offer advantages in terms of recall, automation, and the ability to use multiple instances. Some plugins attempt to model the Vitalizer's circuitry, and while they can come close, discerning ears often note that the hardware still has an edge in terms of depth and analog "mojo."

Integration into Modern Workflows

Despite its analog nature, the SPL Vitalizer MK3-T can be seamlessly integrated into modern, hybrid mixing setups. Its balanced XLR and TRS connections allow for easy patching into analog summing mixers or as an insert on the master bus of a digital audio interface. For those working primarily "in the box," the Vitalizer can serve as a final analog stage before conversion back to digital, adding a touch of analog flavor to otherwise purely digital productions.

Some engineers have found creative ways to utilize the Vitalizer in parallel processing chains, blending its processed signal with the dry signal for more subtle enhancement. This technique can be particularly effective when processing full mixes or subgroups, allowing for precise control over the amount of "vitalizing" applied.

Long-term Reliability and Maintenance

As with any high-end audio equipment, the longevity and reliability of the SPL Vitalizer MK3-T are important considerations. The unit's robust construction and quality components suggest a long service life, but as with any tube-based equipment, periodic maintenance may be necessary. The 12AX7 tubes will eventually need replacement, though their lifespan can be quite long if the unit is well-cared for.

The unit's internal voltage of +/-18V provides ample headroom, which contributes to its clean and dynamic sound. However, it also means that the unit generates some heat during operation. Proper ventilation is essential, especially if the Vitalizer is rack-mounted alongside other equipment.

Conclusion

The SPL Vitalizer MK3-T represents a culmination of decades of audio engineering expertise. It offers a unique approach to sound enhancement that goes beyond simple equalization or dynamics processing. Its ability to unmask and clarify complex audio material makes it a valuable tool in both mixing and mastering contexts.

While it comes with a learning curve and a price tag that reflects its high-end status, engineers who take the time to master its controls are rewarded with a device capable of adding polish and dimension to a wide range of audio material. Its analog circuitry and tube stages provide a character that many find preferable to purely digital solutions.

Ultimately, the SPL Vitalizer MK3-T is not a one-size-fits-all solution, but rather a specialized tool for discerning audio professionals. Its strengths lie in its ability to enhance and clarify without introducing harshness, and its capacity to add depth and dimension to two-dimensional recordings. For those willing to invest the time and resources, it can become an indispensable part of their audio processing toolkit.

Whether used subtly to add a finishing touch to a well-balanced mix or more aggressively to rescue problematic recordings, the Vitalizer MK3-T proves that there's still a place for high-quality analog processing in today's largely digital audio landscape. It's a testament to SPL's commitment to pushing the boundaries of audio technology while respecting the virtues of classic analog design.

TEST: SPL Transducer

 "Is Axel Ritt out of his mind again?" This is likely the question on many readers' minds after the previous paragraphs. "What grand spectacle is he hinting at now?"

Well, anyone who, like me, comes from the guitar-oriented production field understands the sacred cow of guitar recording in the studio. No other topic, not even drum miking, generates as much fuss as the immortalization of an electric guitar amplifier on tape—or rather, hard disk.

There have been countless discussions about microphone choice, distance, angle, open vs. closed cabinets, close miking, ambient miking, Alnico magnets, ceramic magnets, speaker excursion, back electromotive force compression, phase cancellation, and so on.

The fact is, emulation technology has made quantum leaps in recent years and, for example, in the synthesizer domain, it has almost reached the sound quality of hardware components. However, despite immense CPU power and complex algorithms, no one has truly succeeded in capturing a distorted guitar sound through speaker simulation/load resistors/speaker emulations onto tape or hard disk that retains the openness, dynamics, and transparency of a perfectly miked amplifier.

This is where SPL's Transducer steps in, claiming to be the sole link between amplifier and recording medium that can deliver these qualities to producers. Additionally, it promises a signal free of latency due to its hardware-based solution. Rarely have I been so eager to see the test results!

### Construction

The Transducer is a 2U rack unit with a brushed metal finish, giving it a visually appealing and tidy appearance. It features three large knobs, four mini switches, and two LEDs, which control the following parameters:

- **Speaker Action**: Simulates the varying behavior of speakers depending on the volume. Depending on the setting, it can produce a clear sound or the "paper cone distortion" known from overdriven speakers.
- **Sig.**: Indicates whether an input signal is present, lighting up at -20 dBu.
- **Speaker Cabinet**: Generates a more open and transient-rich sound (open back) or a more compressed sound (closed back).
- **Speaker Voicing**: Chooses between the bright and sharp response of an Alnico (aluminum-nickel-cobalt) magnet speaker or the warmer, more mid-centric sound of a ceramic magnet speaker.
- **Miking Level**: Simulates the sound pressure level that hits the microphone. As the sound pressure increases, the microphone compresses more, increasing loudness but losing detail.
- **Microphone Selection**: Switches between the sound characteristics of a condenser microphone and a dynamic microphone. A condenser mic is more detailed and transparent but has less punch than a dynamic mic.
- **Microphone Distance**: Chooses between a direct or slightly ambient recording.
- **Output Gain**: Adjusts the output level of Output 1 and 2.
- **OVL**: Indicates output level overload.

On the back, from left to right, we find the IEC power socket with fuse, a voltage selector switch (115V/220V), power switch, ground lift, Line Out 2 (balanced, XLR + TRS, phase switch), Line Out 1 (balanced, XLR), Microphone Level Output (balanced, XLR), Pre Simulator Out (unbalanced, TRS), Speaker Thru, and Power Input.

The Transducer can handle peak levels up to 200 watts, but for continuous use, it should only be paired with amplifiers up to 100 watts.

### Practical Use

Due to its design, the Transducer can be utilized in various setups, including:

- **Recording without a cabinet**: The Transducer is placed directly after the amp and serves as a load resistor and microphone replacement. Application: recording studio.
- **Live without a cabinet**: The Transducer is placed directly after the amp and serves as a load resistor and microphone replacement. Application: live performance where minimal stage volume is required.
- **Live with a cabinet**: The Transducer is placed between the amp and speaker cabinet, replacing the need for a microphone.
- **Stereo live setup with cabinets**: Using the dry-wet-wet principle, a mono signal is sent dry through the center, and two additional active speakers produce a stereo FX signal.
- **Stereo live setup without cabinets**: Also employs the dry-wet-wet principle but without any cabinets.

Clearly, the developers have made a great effort to cover every possible use case and present the product comprehensively.

### Sound Quality

So, after around 5,000 characters, what everyone has been waiting for: How does the Transducer sound? In short, absolutely fantastic!

In my career as a producer and guitarist, I have tested many similar products and scrutinized them with my ears. Almost all of them had one or more quality issues that ultimately put them far behind traditional miking. Common problems included significant frequency response alterations, excessive compression, and limited signal dynamics, making load resistors perform poorly.

It made no sense to go through the trouble of using a hardware solution (a real amplifier, not plugin simulations) only to have it marred by issues similar to those found in software emulations.

None of these issues are present with the Transducer! Despite the conversion of power into heat, the signal remains transparent and maintains an interactive dynamic I've never experienced before with this type of signal transmission.

The Speaker Action and Miking Level controls are particularly impressive. The signal compression, akin to an overdriven speaker or a compressing microphone, is excellently achieved! The processors here do a remarkable job.

Additionally, thanks to the hardware solution, the Transducer genuinely exhibits no latency, which is invaluable for virtuosic and rhythmically intense playing.

The only advantage real miking has over the Transducer is a broader range of sound options due to different microphone types/manufacturers and cabinet components (volume, wood types). Other than that, the Transducer is on par in terms of quality.

### Conclusion

A significant bastion of audio technology has fallen! With the SPL Transducer, it is indeed possible to simulate the quality of a perfect electric guitar microphone recording to 99%. While the product cannot emulate the diversity of different microphone types, it surpasses all known products in terms of dynamics, transparency, and natural sound, opening a new door in music production.

Gone is the need for a soundproof room to tame the roaring volume of a saturated tube head. With the Transducer, these sounds can be achieved at room volume with the proper knowledge of equalizers and saturation levels.

The fact that live setups are no longer dependent on microphone positioning cannot be overstated. How often has a microphone stand shifted during a show due to a loose screw? How often has a bandmate tripped over a microphone cable, ruining the carefully set mic distance?

In summary, there’s no other way to say it: maximum score! The SPL Transducer is a product that stands out in the field!

### Additional Product Information

#### Speaker Action: More Details

The Speaker Action control is an innovative feature that simulates the behavior of speakers under various volumes. Traditional speakers distort differently depending on the power they receive, creating unique overtones and harmonic content. The "paper cone distortion" it can recreate is especially useful for those looking to capture the raw, edgy sound of an overdriven speaker without the need for high volume levels that could be impractical in many recording situations.

#### Signal Indicators and Practical Use

The Signal (Sig.) indicator is essential for ensuring that input levels are correctly set. Lighting up at -20 dBu, it helps users avoid under-driving or over-driving the input stage, which could lead to suboptimal performance or unwanted distortion. This is particularly useful in live settings where quick visual confirmation of signal presence is necessary.

#### Speaker Cabinet and Voicing

The Speaker Cabinet control allows users to switch between an open back, which offers a more natural and airy sound with rich transients, and a closed back, which delivers a tighter, more focused sound. This versatility ensures that users can tailor the tonal characteristics to fit the mix or live setup precisely. Meanwhile, the Speaker Voicing control's ability to mimic different magnet types (Alnico vs. Ceramic) adds another layer of tonal customization. Alnico magnets provide a vintage, bright, and articulate sound, while ceramic magnets offer a warmer, more mid-range focused tone.

#### Miking Level and Selection

The Miking Level control simulates the sound pressure levels that a microphone would encounter, allowing users to adjust the perceived loudness and dynamic response. This feature is crucial for achieving the natural compression and coloration that microphones impart on high SPL sources. By switching between condenser and dynamic microphone emulations, users can further refine the tonal quality. Condenser microphones, known for their clarity and detail, are ideal for capturing intricate performances, while dynamic microphones provide robustness and punch.

#### Microphone Distance and Output Gain

Microphone Distance settings allow for flexibility in recording techniques, offering both close and room-miked sounds. This is particularly useful for achieving different ambient qualities without physically moving a microphone. The Output Gain controls ensure that the output levels are optimized for various recording or live setups, preventing clipping and maintaining signal integrity.

### Connectivity and Power Handling

The rear panel's comprehensive connectivity options make the Transducer adaptable to any professional setup. The inclusion of balanced and unbalanced outputs, along with a ground lift switch, ensures that users can integrate the unit seamlessly into their existing gear without encountering ground loop issues. The device's ability to handle peak levels up to 200 watts while recommending a 100-watt amplifier for continuous use highlights its robustness and reliability.

### Application Scenarios

- **Studio Recording**: The Transducer excels in studio environments, providing a reliable and versatile tool for capturing high-quality guitar tones without the need for a traditional speaker cabinet and microphone setup.
- **Live Performance**: On stage, the Transducer offers significant advantages by eliminating the need for miking cabinets, thus reducing stage clutter and the risk of mic-related issues such as feedback and inconsistent sound. This can be particularly beneficial in smaller venues or for bands with complex setups where stage space is at a premium.

### Detailed Performance Evaluation

#### Signal Transparency and Dynamics

One of the standout features of the SPL Transducer is its ability to maintain signal transparency despite converting electrical power into heat. This process, which often degrades signal quality in other devices, is handled expertly by the Transducer. The dynamic range remains wide, and the subtle nuances of a guitar performance are preserved, providing a clear and articulate sound that rivals traditional miking techniques.

#### Speaker Action and Miking Level

The Speaker Action and Miking Level controls deserve special attention for their roles in shaping the final output. The Speaker Action control effectively simulates the complex behavior of real speakers at different volumes. When pushed to simulate an overdriven speaker, it produces a convincing "paper cone distortion" that adds a layer of harmonic complexity and grit to the sound. The Miking Level control, on the other hand, allows for fine-tuning the perceived loudness and compression, ensuring that the signal retains its punch and detail even at higher levels.

#### Practicality in Various Environments

The Transducer's versatility makes it an invaluable tool in both recording and live environments. In the studio, it can be used to achieve a wide range of guitar tones without the need for loud volumes, which is ideal for home studios or situations where noise is a concern. Live, it reduces stage volume and the complexity of mic placement, leading to more consistent sound and easier setup.

### Enhanced User Experience

#### Interface and Controls

The user interface of the Transducer is designed with practicality in mind. The large, easy-to-read knobs and switches make adjustments straightforward, even in low-light conditions typical of live performance environments. The clear labeling and logical layout help users quickly understand and utilize the device's capabilities without a steep learning curve.

#### Durability and Build Quality

The Transducer's construction is robust, with a solid metal chassis that can withstand the rigors of both studio and live use. The high-quality components ensure reliability and longevity, making it a sound investment for professionals who need dependable equipment. The brushed metal finish not only looks great but also provides a durable surface resistant to scratches and wear.

### Competitive Edge

#### Comparison with Other Products

Compared to other speaker simulation and load box products on the market, the SPL Transducer stands out for its combination of features, build quality, and sound fidelity. While other products may offer some of these features, few if any provide the same level of detail and control. The ability to simulate both open and closed cabinets, along with the nuanced control over speaker behavior and mic characteristics, sets the Transducer apart.

#### Real-World Applications

In real-world applications, the Transducer has proven to be an invaluable tool. For instance, in a recording studio, it allows engineers to capture high-quality guitar tones without the need for high volumes that can disturb neighbors or require soundproofing. During live performances, it simplifies the setup by eliminating the need for miking cabinets, reducing stage clutter, and ensuring consistent sound.

### Further Product Insights

#### Technical Specifications

- **Frequency Response**: The Transducer offers a flat frequency response, ensuring that no unwanted coloration is added to the signal. This neutrality allows for accurate reproduction of the guitar's natural tone.
- **Impedance**: The device supports various impedance settings, making it compatible with a wide range of amplifiers and speakers.
- **Latency**: As mentioned, the Transducer operates with zero latency, a crucial feature for live performance where timing is everything.
- **Peak Handling**: Capable of handling peak levels up to 200 watts, it ensures that even the most powerful amplifiers can be used without risk of damage.

#### Advanced Usage

For advanced users, the Transducer offers numerous possibilities. For example, combining it with other outboard gear such as EQs and compressors can further refine the sound. The balanced outputs can be routed to multiple destinations, allowing for complex routing setups in both live and studio environments.

#### Educational Value

The Transducer is also an excellent educational tool for those learning about guitar amplification and recording. Its ability to simulate different speaker and mic setups allows students to experiment and understand the impact of these variables on the final sound without needing a vast array of physical equipment.

### Future Developments and Potential Upgrades

Given the success of the SPL Transducer, there is potential for future developments and upgrades. For instance, integrating digital connectivity options such as USB or Ethernet could allow for direct recording to digital audio workstations (DAWs) or integration into digital live sound systems. Additionally, the development of a software interface could provide users with even more control and customization options.

### Customer Support and Community

SPL's commitment to customer support is another factor that makes the Transducer a standout product. The company offers extensive documentation and support to help users get the most out of their equipment. Furthermore, the growing community of Transducer users provides a valuable resource for tips, tricks, and shared experiences.

### Market Reception

Since its release, the SPL Transducer has received positive feedback from both professional and amateur musicians. Reviews often highlight its sound quality, ease of use, and reliability. Many users appreciate the ability to achieve studio-quality recordings at home or maintain consistent sound in live performances without the need for extensive setup and maintenance.

### Conclusion: The Last Bastion Falls

The SPL Transducer represents a significant milestone in audio technology. By successfully simulating the quality of a perfectly miked guitar amplifier, it opens new possibilities for both recording and live performance. Its versatility, combined with its high-quality construction and detailed control options, makes it a must-have for guitarists and audio professionals alike.

Gone are the days of needing a soundproof room to capture high-quality guitar tones. With the Transducer, these sounds can be achieved at manageable volumes, making it an ideal solution for home studios and live performances. The freedom from mic positioning issues alone is a game-changer, offering a level of consistency and reliability that was previously difficult to achieve.

In summary, the SPL Transducer is an exceptional product that delivers on its promises. It stands out in a crowded market, offering unparalleled sound quality and versatility. For anyone serious about guitar recording and performance, the Transducer is an investment that will pay off in spades.

TEST: SPL RPM Series

 When delving into the realm of "German studio technology with international renown," one inevitably lands within a short time at SPL, the company based in Niederkrüchten near Mönchengladbach. As provincial as the place name may sound, the developers of the former "Sound Performance Labs" bring gleaming eyes and upturned corners of mouths to professional sound engineers from near and far. For many years, the company has been producing top-level outboard gear, so that almost every high-quality recording studio can call one or more SPL components in the signal path its own.

Detached from the mostly analog-oriented product range, SPL has also increasingly focused on the development of plug-in technology in recent years, providing the necessary tools to both traditionally anchored and modernly conceptualized sound engineers. Among other things, the RPM series emerged, which celebrates great success among consumers on both levels. SPL was kind enough to put together a current compilation of the analog version of the "Rack Pack," which in its conception represents a brilliant exception among the many outboard gear products.

Construction

Every sound engineer knows the problem, provided they run their productions with the 19-inch variant. If you don't want to take a prefabricated channel strip from manufacturer XY designed in a single housing for sound optimization, but rather split your own compilation into different components, the side rack explodes within a short time. Pre-amp, de-esser, equalizer, and possibly dynamics, maybe all conceived in 2-3 rack units, cause the space requirements in the rack to swell considerably, along with corresponding cabling and signal routing work.

Knowing this problem, SPL relies on the Rack Pack modular system, which consists of a 3U frame including power supply via an external power supply unit, essentially a console concept in miniature. The user can now put together their own channel strip from the RPM series, whereby they no longer have to worry about the power supply, which is provided by the module frame.

For the corresponding signal processing, separate modules can now be acquired, which can be used either individually or in daisy-chain operation. On the rear, the modules have a balanced input and two balanced outputs, so you can, for example, run one output in direct access while routing the second output to the next module for further processing.

The following modules were provided for testing:

Preference Mic-Pre: Balanced instrumentation amplifier
Premium Mic-Pre: High-quality three-stage design with Lundahl transformers and discrete input from high-voltage transistors
TwinTube Module: Tube effect processor
Dual-Band De-Esser Module: Sibilance removal
Bass Ranger: A filter specially designed for the bass range
Vox Ranger: A filter specially designed for the vocal range
Full Ranger: Standard equalizer, full bandwidth
DynaMaxx Module: Compressor

All modules have the same dimensions, only the control elements on the front vary. The overall workmanship is excellent, all components meet the highest standards for longevity and smooth operation.

In Practice

TwinTube: The product is based on two tube circuits which, it can be reported in advance, do excellent work. The generated "saturation" of the signal is additionally given the possibility to process the harmonics of the applied signal through the "Harmonic Processing" circuit. The effect is pleasantly subtle and does not appear excessively radiant even at high doses, as one is accustomed to from some exciter overtones, for example. In doing so, the signal can be helped to more "sprightliness" as well as more "punch" and pressure with correspondingly high dosage. The range of application is wide, from classical vocal areas to percussive signals, the Twin Tube helps almost every signal to get going.

Preference Mic-Preamp / Premium Mic-Preamp: At first glance, no differences in terms of optics can be made out, but the functional scope varies considerably. Both preamplifiers have an analog VU meter, which displays an average in VU mode and peak levels in PPM mode. In addition, both preamplifier types have phantom power, phase reversal, PAD function (-20 dB), and a low-cut filter that intervenes at 75 Hertz with six decibels per octave.

The Preference Mic Pre comes with an IC of type SSM 2019, which represents the first part of a three-stage circuit. To optimize the sound characteristics, an additional sensor stage (recognizing voltage differences) and a summing stage (compensating voltage differences) were built in to minimize any DC components. The Premium, on the other hand, was conceived entirely discretely. The input transformer is a hand-crafted LL1538XL from Lundahl, which generates an additional quality gain in terms of sound. Through galvanic separation, low-frequency hum noises due to potential differences are successfully combated. Both preamps sound excellent, with the Premium having a touch more "exclusivity" in its basic character. The basic sound is soft, very transparent, finely resolved, and has very good clarity, equally suitable for all instrument groups.

Ranger Modules: The individual product names get to the point; the three different modules were sonically designed for special application areas, namely Bass (20 Hz, 60 Hz, 100 Hz, 200 Hz, 500 Hz, 800 Hz, 1.5 kHz, 5 kHz), Vox (120 Hz, 240 Hz, 380 Hz, 800 Hz, 1.2 kHz, 2.5 kHz, 5 kHz, 12 kHz) and Full (31 Hz, 100 Hz, 360 Hz, 720 Hz, 1.5 kHz, 5 kHz, 10 kHz, 17 kHz), all adjustable by +/- 15 dB and equipped with a master output. Unlike traditional equalizers, which set the bands 1 octave apart, the SPL Rangers are based on musical values. Sonically, the filters are beyond reproach, the bands come across as characterful and very "sensitive," but one should clarify in advance whether one can actually get by with a graphic equalizer. Even if the sound result is very good, one or the other may miss the free frequency selection of the parametric filter under certain circumstances.

DynaMaxx Compression: Once again, SPL shows how much effect can actually be imparted to a signal with a minimum of controls, provided the factory settings have sufficient "musicality." With only 2 rotary controls (Compression / Make-Up Gain), the DynaMaxx, which operates in soft-knee mode, manages to get a good grip on the majority of all incoming signals. Via an "FX Com" you can set a preset of 60ms release time, a "Lim." button provides a side-chain limiter also executed as soft-knee, "Link" allows 2 modules to be coupled, and the "De-Com." switch tries to "loosen up" over-compressed audio material dynamically via an expander preset. As with the 19-inch variant, which has been in the SPL catalog for years, only good things can be reported about the RPM DynaMaxx. The handling is comparatively clear despite immense effectiveness and achieves excellent results.

Dual-Band De-Esser: Unlike a conventional de-esser, the SPL module does not work with a frequency-dependent compressor, but via phase reversal. S and Z sounds are automatically recognized and very discreetly, almost imperceptibly eliminated. Due to this process, significantly fewer frequencies in the vicinity of the sibilants are affected, resulting in a more neutral sound. Via a push button, you can select the presets for a male or female voice, the module does the rest automatically. Even with heavy use, the treated sound files remain lively and natural, the use of the de-esser always remains inconspicuous in the background.

Expanding on the Technical Aspects

To provide a more comprehensive understanding of the SPL RPM series, let's delve deeper into some technical aspects and additional features:

Power Supply and Signal Integrity: The RPM series utilizes SPL's proprietary 120V DC audio rail technology. This high-voltage design allows for an extended headroom of up to +34 dBu, resulting in a significantly improved signal-to-noise ratio compared to standard ±15V or ±18V designs. This translates to cleaner, more transparent audio processing across all modules.

TwinTube Module: The TwinTube incorporates two separate tube stages, each with its own character. The "Harmonics" stage adds even-order harmonics for warmth and fullness, while the "Saturation" stage introduces odd-order harmonics for edge and presence. Users can blend these two stages to taste, allowing for a wide range of tonal coloration from subtle warmth to aggressive distortion.

Preference vs. Premium Mic Pre: While both preamps offer excellent performance, the Premium model incorporates several high-end features. The Lundahl input transformer not only provides galvanic isolation but also contributes to the preamp's musical coloration, often described as adding a slight "vintage" character to the signal. The fully discrete signal path in the Premium model also contributes to its lower noise floor and higher headroom.

Ranger EQ Modules: The musical approach to frequency selection in these EQ modules is worth exploring further. Rather than following the standard octave-based layout, SPL has chosen frequencies that correspond more closely to musical intervals. This can make it easier for engineers to make musical decisions when shaping the tone of an instrument or mix. The Q factor of each band is optimized for musical applications, striking a balance between precision and natural sound.

DynaMaxx Compressor: The simplicity of the DynaMaxx belies its sophisticated internal workings. The compressor utilizes a variable mu (tube-style) compression curve, which provides a gentler, more musical compression characteristic compared to VCA-style compressors. The "De-Com" function is particularly interesting, as it can help restore some dynamic range to overly compressed material - a useful tool in mastering applications.

Dual-Band De-Esser: The phase cancellation approach used in this de-esser is notably different from traditional amplitude-based de-essers. By using phase cancellation, the module can reduce sibilance without affecting the overall level of the signal, resulting in a more transparent de-essing effect. The dual-band nature allows for more precise targeting of sibilant frequencies, which can vary between different vocalists.

Integration and Workflow

One of the key advantages of the RPM series is its modular nature, allowing users to create custom signal chains tailored to their specific needs. Here are some potential workflow scenarios:

1. Vocal Recording Chain: Premium Mic Pre > TwinTube > Vox Ranger > Dual-Band De-Esser > DynaMaxx
   This chain provides a high-quality signal path with options for tonal shaping, sibilance control, and dynamics processing.

2. Bass Recording Chain: Preference Mic Pre > Bass Ranger > DynaMaxx
   A straightforward chain for capturing and shaping bass guitar or synth bass sounds.

3. Drum Bus Processing: Full Ranger > DynaMaxx
   Use the Full Ranger for broad EQ adjustments and the DynaMaxx for bus compression on a drum submix.

4. Mastering Chain: Full Ranger > TwinTube > DynaMaxx
   A simple but effective chain for final EQ touches, harmonic enhancement, and master bus compression.

The ability to rearrange modules quickly allows for experimentation with signal flow, which can lead to new and interesting sonic results.

Comparison with Digital Alternatives

While the SPL RPM series represents a high-end analog solution, it's worth considering how it compares to digital alternatives:

Pros of the RPM series:
- Zero latency processing
- Unique analog character, especially in modules like the TwinTube
- Tactile, immediate control without the need for menu diving
- Potentially better integration with other analog gear

Cons:
- Higher cost compared to many digital solutions
- Less flexibility in terms of recall and automation
- Limited to the available modules, whereas digital platforms offer virtually unlimited processing options

For many engineers, the choice between analog and digital is not an either/or proposition. The RPM series can be an excellent complement to a digital workflow, providing high-quality analog processing at critical points in the signal chain.

Long-term Considerations

When investing in a system like the SPL RPM series, it's important to consider long-term factors:

1. Expandability: The modular nature of the system allows for gradual expansion over time. Users can start with a basic setup and add modules as needs and budget allow.

2. Maintenance: While solid-state components generally require little maintenance, the TwinTube module will need periodic tube replacement to maintain optimal performance.

3. Resale Value: High-end analog gear often retains its value well, especially when it comes from a reputable manufacturer like SPL.

4. Future-proofing: Unlike digital gear, which can become obsolete as technology advances, high-quality analog equipment tends to remain relevant and desirable for many years.

Conclusion

The RPM series from SPL manages without compromise to maintain, or rather further develop, the excellent quality of the 19-inch counterparts, some of which have been in the catalog for years. The sound of all tested products is excellent, the handling intuitive, and the workmanship is "Made in Germany" in the best sense, designed for eternity.

It goes without saying that this collection of quality with domestic production has its price. Nevertheless, in return, you get products that convince across the board and, above all, put the necessary "musicality" in the foreground. These are not pure engineers at work who fall in love with measurement curves and provide chatty forum nerds with meaningless content through 19-inch "waffle," but rather musicians/artists who try to refine sounds with technology, and you can hear that.

My tip: test it, listen to it, and save up if necessary until you have the money together. What you've messed up in the first recording stage can never be resolved from the sonic context, so in the end, it's always worth investing in German quality work of the caliber of an SPL.

The SPL RPM series represents a significant investment in analog processing technology. Its modular approach offers flexibility and scalability, allowing users to build a custom signal chain that meets their specific needs. While the cost may be prohibitive for some, the quality of construction, sound, and longevity of these units make them a worthwhile consideration for professional studios and discerning home recordists alike. As with any major studio equipment purchase, potential buyers should carefully consider their needs, budget, and workflow before making a decision. However, for those who value the unique characteristics of high-end analog processing, the SPL RPM series offers a compelling solution that combines classic audio engineering principles with modern manufacturing techniques.

TEST: SPL Reducer

 Adjustable load resistor... let's pause for a moment, observe the occasionally pensive faces of the inclined audience... and then shoot from the hip with an explanation. An adjustable load resistor is placed between the power amp and the speaker, converting part or all of the amplifier's output energy into heat. Now, question marks have permanently etched themselves into the incredulous faces of the interested musicians, and an overarching question hangs in the air: what on earth is this good for?

The short answer: Tube amplifiers have the unfortunate habit of only developing their full tonal volume above a certain operating volume. Anyone who has ever stood next to an old non-master full stack being driven into saturation knows what I'm talking about. Along with a maximum of transparency, dynamics, and interaction with the guitar's volume control comes the unfortunate fact that the produced volume is only remotely usable at large open-air events or halls with at least five-digit capacities.

To salvage a maximum of sound without sending one's hearing to the eternal hunting grounds or tempting the FOH engineer to throw hard objects at you, there are the aforementioned products, also known as loadboxes in the Anglo-American realm. Germany's hardware elite forge SPL has also taken on this topic and brings to market the Reducer, a purely passive product that comes without any D.I. function in the style of the Transducer or Cabulator.

Construction

At first glance, one can see the massive construction of the Reducer. Strong, perforated metal sheets as floor and ceiling, along with heat sinks as side panels, allow the heat produced inside to dissipate well. The little box with dimensions of 85 mm x 208 mm x 179 mm rests on 4 massive and expectedly high rubber feet, allowing it to be placed on a head with a carrying handle on the one hand, and not hindering air circulation on the other.

What distinguishes the Reducer from almost all of its competitors is the switchable impedance for the used cabinet. While most loadboxes are designed for a fixed ohm number, here you can choose between the standards 16, 8, and even the less used 4 ohms. In terms of volume reduction, 2 controls share the management. You select a rough pre-setting via the control ranges 0dB, -3dB, -5dB, and "Variable", to then in the last range, starting at -7dB, optionally drive the volume down to infinity. As a very rough orientation, a reduction of 3dB corresponds to approximately halving the volume.

On the rear, there are only 2 jack sockets, whose labeling is readable both regularly and from above. A seemingly small detail, but all the more valuable when you're bending over the amp in the semi-darkness of the stage.

In Practice

The main area of application for the Reducer is likely to be the vintage fraction of the all-tube department, because only here does the reduction of volume, which seems idiotic at first glance, make sense. Highly bred multi-channel amps or even transistor amplifiers will hardly or not at all appreciate the forceful intervention in the master volume.

A vintage amp, however, whose power amp is nicely compressed, whose phase driver is already rattling a bit, and whose power supply is wheezing slightly, can generate the maximum sound here to then tame it with the Reducer. By the way, NEVER fully drive a tube amp, then the amp only sounds harsh, mushy, and indifferent. Forget the old "everything-on-10" myth, that's pure nonsense, a good sound can be achieved up to a maximum of 80% load!

And the sound of the Reducer? If you keep in mind that the subjectively perceived sound always shifts somewhat towards mid-presence with the reduction of volume due to the physical conception of our hearing, and you have to readjust the tone control accordingly, you can only confirm a very good for the Reducer. If you are aware of this circumstance, you will not want to miss the gained dynamics and the increasing pressure of the amplifier.

Expanding on the Technical Aspects

To delve deeper into the technical prowess of the SPL Reducer, it's worth examining some of its key specifications and design features:

1. Power Handling: The Reducer is capable of handling up to 100 watts of continuous power, making it suitable for most guitar amplifiers on the market. This includes vintage classics like the Marshall JMP, modern high-gain monsters, and everything in between.

2. Impedance Switching: As mentioned earlier, the ability to switch between 4, 8, and 16 ohms is a standout feature. This flexibility allows the Reducer to work with virtually any guitar amplifier and speaker cabinet combination. The impedance switch is a robust, high-quality component designed to withstand frequent use without degradation.

3. Attenuation Range: The Reducer offers a wide range of attenuation options. The stepped attenuator provides fixed settings of 0dB (bypass), -3dB, and -5dB. The variable control allows for fine-tuning from -7dB down to complete silence. This range covers everything from subtle volume reduction to silent recording scenarios.

4. Heat Dissipation: One of the critical aspects of any loadbox is its ability to dissipate heat effectively. The Reducer's design incorporates large heatsinks and a perforated casing to ensure optimal airflow. This allows the unit to handle high-powered amplifiers for extended periods without risk of overheating.

5. Passive Design: The Reducer is a completely passive device, meaning it requires no power supply. This not only simplifies setup but also eliminates any potential for added noise or interference that can sometimes occur with active devices.

6. Frequency Response: SPL has designed the Reducer to maintain a flat frequency response across the entire audible spectrum. This ensures that the tonal characteristics of your amplifier are preserved, even when heavily attenuated.

7. Component Quality: SPL is known for using high-grade components in their products, and the Reducer is no exception. The resistive elements are precision-matched and rated for high power handling, ensuring consistency and reliability over time.

Integration into Modern Setups

While the Reducer is primarily designed for traditional tube amplifier setups, its utility extends into modern, hybrid rigs as well. Here are some scenarios where the Reducer can prove invaluable:

1. Home Recording: Many guitarists prefer the sound of a pushed tube amplifier for recording, but achieving this in a home studio environment can be challenging due to volume constraints. The Reducer allows for capturing that sweet spot of tube saturation at manageable volume levels.

2. Live Performance: In smaller venues or on stages with strict volume limitations, the Reducer can help guitarists achieve their preferred tone without overpowering the mix or incurring the wrath of sound engineers.

3. Silent Practice: By using the Reducer in conjunction with a reactive load box or IR (Impulse Response) loader, guitarists can practice silently while still utilizing their favorite amplifier.

4. Amp Modeling: For those using digital modeling systems, the Reducer can be an excellent tool for capturing the power amp characteristics of a real tube amplifier at lower volumes. This can then be fed into an IR loader for a complete "virtual" rig.

Comparison with Active Attenuators

It's worth noting that the SPL Reducer differs from some popular attenuators on the market in that it's a purely passive device. Active attenuators, such as the Universal Audio OX or the Two Notes Torpedo, offer additional features like built-in IR loading, USB connectivity, and even mobile app control. However, these come with their own set of pros and cons:

Pros of Passive Attenuators like the SPL Reducer:
- No need for external power
- Generally more reliable due to simpler design
- Often more transparent in terms of tone
- Usually more affordable

Cons:
- Lack of additional features like IR loading or DI outputs
- No ability to shape the tone beyond attenuation

The choice between active and passive attenuators often comes down to individual needs and preferences. The SPL Reducer caters to purists who want the most direct and transparent path between their amplifier and speaker, with the added benefit of volume control.

Long-term Considerations

When investing in a piece of equipment like the SPL Reducer, it's important to consider its long-term value and usability:

1. Durability: The robust construction and high-quality components used in the Reducer suggest a long operational life. This is particularly important for a passive device that will be handling high power levels and generating significant heat.

2. Resale Value: SPL has a strong reputation in the pro audio world, which often translates to good resale value. Unlike digital devices that can become outdated, a well-designed passive attenuator like the Reducer is likely to remain relevant and desirable for many years.

3. Versatility: The ability to work with different impedances and a wide range of amplifiers means the Reducer can adapt to changes in your rig over time. Whether you're switching between vintage and modern amps or experimenting with different speaker cabinets, the Reducer should remain a useful tool.

4. Maintenance: One advantage of passive devices is their low maintenance requirements. The Reducer should require little more than occasional cleaning and checking of connections to ensure optimal performance.

User Experience and Workflow Integration

The effectiveness of any piece of gear ultimately comes down to how well it integrates into a musician's workflow. The SPL Reducer, with its straightforward design and operation, offers several advantages in this regard:

1. Intuitive Controls: The simple layout of the Reducer means that users can quickly dial in their desired attenuation without navigating complex menus or digital interfaces. This can be particularly valuable in live situations where time and simplicity are of the essence.

2. Transparency: For many guitarists, preserving the natural interaction between their instrument, amplifier, and speaker is crucial. The Reducer's passive design aims to maintain this connection as much as possible, even at reduced volumes.

3. Consistency: Unlike some attenuators that can alter the tonal character of an amplifier differently at various volume levels, the Reducer aims to provide a consistent experience across its attenuation range. This allows users to find their preferred settings and rely on them gig after gig.

4. Flexibility in Placement: The compact size and robust construction of the Reducer allow for flexible placement options. It can be easily integrated into a rack setup, placed on top of an amplifier head, or positioned on the floor near a combo amp.

Potential Limitations and Considerations

While the SPL Reducer offers many benefits, it's important to consider potential limitations or scenarios where alternative solutions might be preferable:

1. Lack of Speaker Simulation: Unlike some high-end attenuators, the Reducer doesn't offer built-in speaker simulation or loadbox functionality for silent recording. Users needing these features would need to combine the Reducer with additional equipment.

2. No Tone Shaping: Some attenuators offer the ability to shape the EQ or add effects. The Reducer's purely passive design means it doesn't provide these options. For some users, this simplicity is a benefit, while others might prefer more tone-sculpting capabilities.

3. Volume Reduction vs. Tone: While the Reducer aims to preserve tone as much as possible, the laws of physics dictate that some changes in perceived tone are inevitable as volume decreases. Users should be prepared to make minor adjustments to their amp settings to compensate for this at lower volumes.

4. Power Handling Limitations: While the 100-watt rating covers most guitar amplifiers, users with very high-powered amps (like some bass rigs) might need to look at alternatives with higher power handling capabilities.

Conclusion

With the Reducer, SPL has a very hot iron in the fire when it comes to loadboxes. Excellent workmanship, outstanding components, and an excellent sound let it leap to the pole position of adjustable load resistors.

The SPL Reducer represents a well-executed implementation of a straightforward concept. It offers guitarists a reliable tool for managing volume while preserving the essential character of their amplifiers. Its simplicity and transparency will appeal to purists who want minimal intervention between their amp and speaker.

While it may lack some of the bells and whistles of more complex attenuation systems, the Reducer excels in its primary function. It's a solution that respects the traditional signal path of guitar, amplifier, and speaker, while providing the crucial ability to manage volume in today's diverse playing environments.

For vintage amp enthusiasts, home recordists, and gigging musicians dealing with volume restrictions, the SPL Reducer offers a compelling option. Its build quality, flexibility, and sound performance position it as a serious contender in the world of guitar attenuators.

Ultimately, the value of the SPL Reducer will be determined by individual needs and preferences. For those seeking a no-frills, high-quality passive attenuator, the Reducer certainly deserves consideration. It stands as a testament to SPL's commitment to sound quality and practical design, offering a solution that bridges the gap between vintage tone and modern volume requirements.

TEST: SPL PQ

 It's always fascinating when two diametrically opposed worlds collide head-on, engaging in their beloved trench warfare. A battle that has been raging for decades now primarily takes place in our beloved recording studios, regardless of their size, level of professionalism, or equipment. We're talking about internal versus external, hardware versus software, or more precisely, outboard gear versus plugins. It's tedious to rehash the oft-cited arguments about price, sound quality, habitus, and the "completely dumbed-down ear of the consumer," which we won't be doing here.

However, a current interim report on the state of play would note the introduction of a new player on the outboard gear team, one that's attracting attention with its massive presence and a very high transfer fee. We're referring to the new flagship from the German 19-inch rack specialist SPL, which is sending the SPL PQ, a formidable colossus, onto the playing field. Let's make way for an equalizer of a very special kind.

Construction

The SPL PQ enters the arena as a mastering stereo equalizer, filling a niche that nowadays is mostly handled entirely digitally within the DAW. Alongside compressors and limiters, all types of EQs are found in the signal chain, at the end of which stands the final stereo file. It's becoming increasingly rare for the sum to be converted again before the final mix and sent through corresponding outboard gear, and when it is, this is usually reserved for more economically advantaged studios. High-quality conversion with appropriate management requires maximum quality in the signal flow to ensure that rerouting the signal is sonically worthwhile and doesn't potentially reduce the quality of the end product. To guarantee this, the product used must possess quite a few features that the plugin armada cannot offer. We're curious to see if it's worth putting down nearly five and a half grand for this top dog.

In terms of dimensions and weight, the SPL PQ falls into the same category as the recently released SPL Iron compressor. Four rack units high and weighing over 15 kilograms, this product, once laboriously unpacked, immediately finds its way into the rack, never to be moved again. As always with SPL, the workmanship is perfect, and the construction is solid down to the last detail. The behemoth is available in black and red.

Controls

Even though the 30 black rotary knobs with 41 detents each, along with 22 push buttons and several mini-switches, might initially leave the user in awe, the SPL PQ appears very familiar, almost "normal" upon second glance. Five fully parametric bands per channel may represent a multiple of what conventional analog equalizers offer the user, but in use, they are virtually self-explanatory. SPL employs their proprietary 120-volt technology, which stands for maximum headroom in the processing and minimal coloration of the signal. Thus, they confront the usual audio circuits, which operate with +/- 15 volts, with an operational amplifier level of +/- 60 volts, which allows for an almost twice as high dynamic range compared to conventional circuits.

As with the SPL Iron, the Stereo Link and Auto-Bypass functions have been integrated into the central control panel, with the latter function deserving special attention. A rotary control allows you to set a time interval at which the SPL PQ automatically switches on and off. This is intended to keep the ear fresh and prevent the switching from being done by hand, which might prepare the ear for the expected difference. A very practical feature.

The Stereo Link switch causes both channels to adopt the settings of the right channel's bypass switch and proportional Q switch. Since the device is essentially designed as a dual mono device, the controls on both sides still need to be adjusted manually. However, this also allows operation as two high-end mono EQs, which will undoubtedly find its application in practice.

A look inside the product makes the German engineer's heart beat faster. Excellent workmanship made in Germany, oversized components like the built-in toroidal transformer, good heat dissipation, and optimal shielding between components speak a clear language. Another special feature is the very large overlap of possible frequencies within the frequency bands. Up to three bands can share and process a specific frequency range.

However, with extreme processing, one should keep an eye on the signal chain after the SPL PQ. Due to the 120-volt technology, the SPL PQ works internally without distortion, but the device does not have an output control. Therefore, one should always keep an eye on the input range behind the EQ to ensure that subsequent products don't negate the painstakingly generated distortion-free signal. However, a toggle switch can, if necessary, quarter the +/- 20 dB level setting, resulting in a +/- 5 dB version.

In Practice

But what good are the best measurements and most massive constructions if the sound doesn't at least somewhat justify the hefty price tag? This brings us to the next dilemma. What does "good sound" even mean? Isn't this ultimately a deeply subjective perception? Aren't we mixing and mastering for a clientele that still attests to a good sound on a thoroughly catastrophically overdriven album like "Death Magnetic"?

Therefore, one should first consider the basic orientation of the SPL PQ. If one wanted to encapsulate the basic sound of the EQ in an adjective, only the word "neutral," paired with "clean," comes to mind. What at first glance seems unbeatable in terms of irrelevance turns out, upon close listening, to be a precision instrument that captures individual frequencies with surgical accuracy and deliberately bends the frequency curves. The targeted saturation with which other devices flatter the ear through overtones and compression will not be found here. The SPL PQ simply has no inherent sound, which cannot be valued highly enough in the realm of a mastering EQ.

Even slight level adjustments have a very strong impact on the overall sound and effortlessly assert themselves in the soundscape. Here, the ability to switch between a "constant" and a "proportional" Q works true musical wonders. This switch influences the bell shape of the Q factor. In the constant Q setting, the Q factor always remains the same, regardless of how much the filter band is boosted or cut. A proportional Q filter, on the other hand, increasingly incorporates neighboring frequencies into the work process with stronger processing, increasing the bell shape. For targeted interventions in the sound image, one will tend to resort to the constant Q variant, while a proportional Q filter works more "musically."

Expanded Technical Specifications

To delve deeper into the technical prowess of the SPL PQ, let's examine some of its key specifications:

1. Frequency Range: The SPL PQ covers an expansive frequency range from 10 Hz to 30 kHz, ensuring that even the most subtle sub-bass and high-frequency details can be manipulated with precision.

2. Filter Types: Each of the five bands per channel offers a choice between peak, high shelf, and low shelf filter types, providing maximum flexibility for shaping the frequency response.

3. Q Factor Range: The Q factor can be adjusted from 0.5 to 15, allowing for extremely narrow surgical cuts or broad, smooth boosts.

4. Gain Range: Each band offers +/- 15 dB of boost or cut, with 0.5 dB increments for fine-tuning.

5. THD+N: Less than 0.001% at +4 dBu input level, showcasing the unit's exceptional clarity and low distortion.

6. Dynamic Range: Greater than 125 dB, thanks to the 120V rail technology, surpassing most digital systems.

7. Frequency Response: +0 / -0.5 dB from 10 Hz to 100 kHz, ensuring transparency across the entire audible spectrum and beyond.

8. Crosstalk: Better than -90 dB at 10 kHz, maintaining excellent channel separation.

9. Input Impedance: 10 kΩ balanced, allowing for easy integration with a wide range of audio equipment.

10. Maximum Input Level: +34 dBu, providing ample headroom for even the hottest signals.

11. Output Impedance: 150 Ω balanced, ensuring optimal signal transfer to subsequent devices.

12. Maximum Output Level: +34 dBu, matching the input capabilities and maintaining signal integrity throughout the chain.

Additional Features and Considerations

The SPL PQ's design philosophy extends beyond mere technical specifications. Its user interface has been meticulously crafted to enhance workflow efficiency in professional mastering environments. The large, easily readable VU meters provide instant visual feedback on signal levels, while the Auto-Bypass function, with its adjustable interval, proves invaluable during extended mastering sessions by combating ear fatigue.

One aspect that sets the SPL PQ apart from many of its competitors is its dual-mono design. This approach allows for true stereo processing when needed, but also opens up possibilities for creative mid-side processing techniques. By treating the left and right channels independently, mastering engineers can address stereo image issues with unprecedented precision.

The unit's build quality deserves further mention. The robust chassis isn't just for show; it provides excellent shielding against electromagnetic interference, a crucial consideration in today's studios filled with potential sources of noise. The high-quality potentiometers and switches are rated for thousands of hours of use, ensuring longevity in demanding professional environments.

Comparison with Digital Alternatives

While the SPL PQ stands as a monument to analog excellence, it's worth considering how it compares to high-end digital equalizers. Many will argue that top-tier plugins can achieve similar results at a fraction of the cost. However, the SPL PQ offers several advantages that are difficult to replicate in the digital domain:

1. Analog Warmth: While the SPL PQ is designed for neutrality, it still imparts a subtle analog character that many find pleasing, especially when pushing the unit to its limits.

2. Tactile Control: The physical interaction with high-quality knobs and switches provides a level of control and connection to the music that many find lacking in mouse-based interfaces.

3. Zero Latency: Unlike digital systems, which introduce some degree of latency, the SPL PQ operates in real-time, allowing for immediate audition of changes.

4. Reliability: With no reliance on computer systems or software updates, the SPL PQ offers a level of stability and longevity that can be appealing in mission-critical studio environments.

5. Resale Value: High-end analog gear often retains its value better than digital alternatives, which can become outdated as technology advances.

Integration into Modern Workflows

Despite its analog nature, the SPL PQ is designed to integrate seamlessly into modern, hybrid studio setups. Its balanced XLR inputs and outputs allow for easy connection to high-end AD/DA converters, enabling its use as an insert in a DAW-based workflow. This flexibility allows engineers to combine the best of both worlds, leveraging the SPL PQ's analog processing alongside digital plugins and editing tools.

For studios working primarily in the digital domain, incorporating the SPL PQ into the signal chain requires careful consideration of the conversion process. The quality of the AD/DA converters used becomes crucial, as any shortcomings in the conversion stage could negate the benefits of the SPL PQ's pristine analog circuitry. This consideration further underscores the importance of viewing the SPL PQ as part of a holistic mastering system rather than an isolated component.

Long-term Considerations

Investing in a piece of equipment like the SPL PQ is a significant decision that goes beyond immediate sonic benefits. Prospective buyers should consider the long-term implications:

1. Maintenance: While built to last, any analog device will require periodic maintenance to ensure optimal performance. Factoring in the cost of professional servicing and potential part replacements is advisable.

2. Future-proofing: As digital technology continues to advance, the question arises of how long top-tier analog gear will remain competitive. However, the enduring appeal of classic analog equipment in many studios suggests that well-designed analog tools like the SPL PQ may have a longer shelf life than some digital alternatives.

3. Training and Familiarity: Mastering engineers accustomed to working entirely in the box may face a learning curve when incorporating the SPL PQ into their workflow. The investment in time to fully understand and leverage the unit's capabilities should be considered part of the overall cost.

4. Client Perception: In some markets, the presence of high-end analog gear like the SPL PQ can be a selling point for a studio, potentially attracting clients who value a hybrid analog/digital approach.

Conclusion

With the SPL PQ, Wolfgang Neumann's team has brought a mastering EQ to market that is poised to overshadow everything that has come before. It's difficult to list points that the SPL PQ wouldn't fulfill or deliver to perfection.

Brilliant detailed solutions, extremely high-quality workmanship, and a sound that can only be described as "outstanding" in terms of flexibility and neutrality leave any doubter sitting mutely in the corner, unless they bring up the eternal topic of retail price.

As always in SPL's high-end range, it's simply pointless to discuss the price, as a true price/performance ratio cannot be established. The device has everything that triggers an official "aha" effect, visually and acoustically; more "showing off" is virtually impossible.

Here, everyone must decide for themselves whether the ultimate sound is worth a price beyond the 5,000 euro mark or not, period. One doesn't discuss with a Tesla driver whether the vehicle represents a real equivalent value for the purchase price.

The SPL PQ represents the pinnacle of analog equalizer design, offering uncompromising sound quality and flexibility for the most demanding mastering applications. Its hefty price tag will undoubtedly limit its accessibility to top-tier professional studios and well-heeled enthusiasts. However, for those who can justify the investment, the SPL PQ promises to be a powerful tool in the pursuit of sonic excellence, capable of imparting that elusive final polish to productions across all genres of music.

Ultimately, the value of the SPL PQ will be determined by the ears and workflows of the engineers who use it. In a world increasingly dominated by digital solutions, it stands as a testament to the enduring appeal of meticulously crafted analog equipment. Whether it becomes a new industry standard or remains a niche product for analog purists, the SPL PQ has undeniably raised the bar for what's possible in the realm of mastering equalizers.

TEST: SPL Phonitor XE

 A review of an SPL product made in Germany is always a particular pleasure for me, not only because of the guaranteed high manufacturing quality but also due to the 50% disapproving comments about the consistently high prices of the Niederkrüchten-based company. The two camps quickly become irreconcilably opposed, essentially repeating their arguments in a mantra-like fashion, with "Product XY is much cheaper and just as good" on one side and "But it's the best there is" on the other. Whether this product will lead to another such discussion remains to be seen in the upcoming test. After all, the SPL Phonitor XE comes with a retail price of €2,099 and, depending on the version, ranks among the top 4 or top 9 most expensive headphone amplifiers in the Thomann music store's portfolio.

The Concept of the SPL Phonitor XE

It's likely known to every reader that SPL has held a firm place in the top league of headphone amplifiers for decades, especially since the Phonitor series secured a permanent spot in many pro studios with the introduction of the legendary matrix circuit. With the SPL Phonitor XE model, SPL is now bringing a new flagship to the market. Unlike its counterpart, the Phonitor X, which can also function as a preamp for signal distribution with its XLR outputs, the XE functions as a pure headphone amplifier. Needless to say, at this price point, the focus is on meeting the highest standards.

The buyer has a choice between two models, with and without a D/A converter, with the integrated DAC768 converter adding €700 to the price. Which model to prefer primarily depends on the personal setup of the studio. If you haven't installed a converter yet, it's worth considering the second variant. Like all other top-tier products from SPL, the SPL Phonitor XE also runs on the patented 120 V technology, which provides a significantly more relaxed headroom during operation.

The fact that SPL has expanded its competencies beyond the pro sector, particularly in the Hi-Fi sector in recent years, is evident in the product's visual appearance, along with the typical "plate feet" that have been used in the Hi-Fi sector for ages. The SPL Phonitor XE thus visually demonstrates its dual orientation, targeting two groups: the pro user in the recording studio and the ambitious Hi-Fi fan. The general visual impression is correspondingly "massive," impressively underlined by a weight of nearly 5 kilograms. For a wider visual selection, the product can be purchased in black, silver, and red to match the respective ambiance.

The first special feature of the SPL Phonitor XE is found on both the front and back of the amplifier in the form of a digital XLR-4 headphone output, which is present along with a standard TRS output. A mini-switch on the front of the housing allows you to choose whether to connect your headphones on the front or the mirrored back. A real blessing when I think about how often the headphone cable stretching across the desk has gotten on my nerves.

The Rear Panel

In terms of connections, SPL exhausts the entire bandwidth, except for the TRS connectors that are almost never used in this segment. For the analog area, there are lockable, balanced XLR sockets in addition to gold-plated RCA connectors (RCA and then gold-plated, actually a contradiction in itself ;-). In the digital realm, the product offers 4 different ways to process the signal with AES, Coaxial, optical, and USB.

The possible conversion rates of the built-in D/A converters from AKM (AK4490) are as follows:

AES/EBU (XLR), PCM sampling rates: 44.1 / 48 / 88.2 / 96 / 176.4 / 192 kHz
Coaxial SPDIF (RCA), PCM sampling rates: 44.1 / 48 / 88.2 / 96 / 176.4 / 192 kHz
Optical SPDIF (Toslink F06), PCM sampling rates: 44.1 / 48 / 88.2 / 96 / with fiber optic < 1m: 176.4 / 192 kHz
USB (B), PCM sampling rates: 44.1 / 48 / 88.2 / 96 / 176.4 / 192 / 352.8 / 384 / 705.6 / 768 kHz
USB (B), DSD over PCM (DoP), sampling rates: 2.8 (DSD64), 5.6 (DSD128), 11.2 (DSD256) MHz

There's also a push button for IR programming, allowing any standard remote control to be used for controlling the headphone amplifier. Additionally, there's the IEC socket, the power switch, and the corresponding voltage selection. To activate the product from the front as well, SPL has installed an additional standby mini-switch on the front panel.

The Front Panel

Always a welcome sight, but besides their retro look, also electronically a highlight for me personally due to their comparatively sluggish response: 2 VU meters, separate for the right and left channels. Depending on the incoming level, the displays can be adjusted in sensitivity by 6 or 12 dB via a mini-switch below the left VU meter. Since the SPL Phonitor XE is designed for the classic solo producer in the studio, the device only has one headphone output each, which can adequately cover headphones in the lower double-digit as well as the higher triple-digit ohm range.

Here's a brief list of the key data for headphone operation:

XLR 4 (digital)
Source impedance: 0.36 Ω
Damping factor (40 Ω): 180
Frequency response (-3 dB): 10 Hz – 300 kHz
Crosstalk (1 kHz): -90 dB
THD + N (10 Hz – 22 kHz, 0 dBu): 0.00082 %
Noise (A-weighted): -98 dBu
Output power (1 kHz, 1% THD, 600 Ω): 2 x 8 W
Output power (1 kHz, 1% THD, 250 Ω): 2 x 3.5 W
Output power (1 kHz, 1% THD, 32 Ω): 2 x 0.7 W
Dynamic range: 130.5 dB

TRS
Source impedance: 0.18 Ω
Damping factor (40 Ω): 180
Frequency response (-3 dB): 10 Hz – 300 kHz
Crosstalk (1 kHz): -90 dB
THD + N (10 Hz – 22 kHz, 0 dBu): 0.00082 %
Noise (A-weighted): -103 dBu
Output power (1 kHz, 1% THD, 600 Ω): 2 x 2.7 W
Output power (1 kHz, 1% THD, 250 Ω): 2 x 5 W
Output power (1 kHz, 1% THD, 32 Ω): 2 x 1 W
Dynamic range: 135.5 dB

The eye-catcher on the front is the Alps-RK27 level control, which turns with the famous "spoon in a honey jar" feel. The left front side is dominated by the input selection and a triple panorama selection (Mono, Stereo, and Laterality with Stereo Sum Panorama rotary control) from the SPL matrix. In this device, the matrix has been limited to the Crossfeed (crosstalk degree of the simulated monitors) and Angle (angle of the stereo triangle) controls. Additionally, the matrix can be switched on and off with a mini-switch. Lastly, the product has two DIP switches on the bottom of the housing, which can be used to adjust the input level for the RCA input (-10dBV/0 dBu) and boost the headphone output with a level increase of 22 dB.

The SPL Phonitor XE in Practice

Let's start with the haptics of the product. As expected, all controls and switches of the SPL Phonitor XE meet the highest standards. The controls are grippy, engage cleanly, and convey a very high-quality feel during switching. The same applies to the switches, which, above all, do not exhibit the notorious "wobble" of less expensive counterparts.

Sonically, the result can be summed up in one word: outstanding! It's hard to put into words how relaxed, detailed, and yet voluminous the SPL Phonitor XE sounds in its entirety. On my Beyerdynamic T1 reference headphones, the amplifier impressed in all aspects and at all volumes. It particularly excelled in terms of dynamics and allowed for relaxed work over several hours without any problems.

A quick word about two special features of the SPL Phonitor XE: the adjustable stereo balance and the matrix. People with hearing impairments will particularly benefit from the Laterality control, as they can find an appropriate stereo center using this control at the first signs of asymmetric deafness. An unusual but very helpful bonus for the affected target group.

The matrix, on the other hand, remains the secret star of the Phonitor series, as it manages to bring together the always unnaturally sounding phantom center of the extreme stereo arrangement of the individual speakers into a naturally sounding result. As is known, there is no situation in nature where a corresponding spatial effect would not be shown due to time delay, which makes the listening pleasure of a signal appear significantly more natural in terms of depth layering. Definitely worth a listen!

Additional Insights

The SPL Phonitor XE's 120V technology deserves a closer look. This patented approach significantly increases the operating voltage compared to standard designs, resulting in several benefits. The higher voltage allows for a larger dynamic range and lower noise floor, which translates to a cleaner, more detailed sound. This is particularly noticeable when listening to complex musical passages or during critical mixing sessions where every nuance matters.

The matrix circuit, a hallmark of SPL's Phonitor series, is more than just a gimmick. It addresses a fundamental issue in headphone listening: the unnatural stereo image that results from having two isolated channels delivered directly to each ear. By simulating the crosstalk and time delays that occur in speaker listening, the matrix creates a more natural, speaker-like experience. This is especially valuable for mixing engineers who need to make critical decisions about stereo placement and depth.

The Laterality control is an often-overlooked feature that can be a game-changer for some users. Beyond its utility for those with hearing impairments, it can be useful in various scenarios. For instance, it can compensate for slight channel imbalances in headphones or recordings, or it can be used creatively to adjust the stereo image without affecting the overall volume.

Build quality is another area where the SPL Phonitor XE shines. The use of high-quality components throughout, from the Alps potentiometer to the gold-plated connectors, ensures not only excellent sound quality but also long-term reliability. The robust construction and attention to detail in the design speak to SPL's commitment to creating professional-grade equipment that can withstand the rigors of daily studio use.

The inclusion of both XLR and TRS headphone outputs provides flexibility for users with different headphone terminations. The ability to switch between front and rear outputs is a thoughtful touch that can significantly improve cable management in cramped studio environments.

While the SPL Phonitor XE is primarily designed for professional use, its features and sound quality make it equally appealing to discerning audiophiles. The combination of high power output, low noise floor, and the unique matrix circuit can breathe new life into high-end headphones, revealing details and nuances that might be missed with lesser amplifiers.

The DAC option is worth considering for those looking to simplify their signal chain or upgrade their digital-to-analog conversion. The AKM AK4490 chip used in the DAC768 version is well-regarded in audiophile circles for its natural, musical sound. Its ability to handle high-resolution PCM and DSD files makes it future-proof for those with extensive digital music libraries.

One potential drawback of the SPL Phonitor XE is its size and weight. While this contributes to its solid build and impressive performance, it may not be ideal for those with limited desk space or who need a more portable solution. However, for those who can accommodate it, the substantial build inspires confidence and helps to isolate the sensitive audio circuitry from external vibrations.

The price point of the SPL Phonitor XE places it firmly in the high-end category, which may put it out of reach for some users. However, when considering its build quality, performance, and unique features, it represents good value for professionals and serious enthusiasts who demand the best possible headphone listening experience.

In the context of SPL's product line, the Phonitor XE represents a sweet spot between the more affordable Phonitor models and the top-of-the-line Phonitor x. It offers most of the features and performance of its more expensive sibling but in a more compact form factor and at a lower price point.

Conclusion

The SPL Phonitor XE once again sets the bar very high for the competition. The amplifier sounds outstanding in all respects, is excellently crafted, and offers two bonus features with the Laterality control and the Matrix circuit, which crown an already very high-quality product.

For professionals working primarily with headphones, the SPL Phonitor XE could be considered an essential tool rather than a luxury. Its ability to provide a speaker-like experience through headphones can significantly improve the accuracy of mixes and reduce ear fatigue during long sessions.

While the price may be a barrier for some, those who invest in the SPL Phonitor XE are likely to find it a long-term solution to their headphone amplification needs. Its versatility, build quality, and unique features make it a product that can grow with the user's needs and continue to provide value for years to come.

In the realm of high-end headphone amplifiers, the SPL Phonitor XE stands out not just for its technical specifications, but for the thoughtful design choices that address real-world needs of audio professionals and enthusiasts alike. It's a product that demonstrates SPL's deep understanding of both the science of audio and the practical needs of its users.

Absolute top class!