TEST: Rupert Neve Design RNDI

 "Oh dear, what is so interesting about a D.I. box?" These or similar sentences will probably already be going through the mind of the interested reader when they read the title of this test. OK, D.I. boxes are the kind of little helpers in the background that only appear when a.) they are defective or b.) there are not enough of them. But what if one of the biggest names in audio engineering and the inventor of the mixing console brings out such a box and puts his name to it?

This is the case with the Rupert Neve Designs RNDI and is guaranteed to cause a not insignificant number of fans to frown in interest. What would you really want to change about a DI box? Does it perhaps even have an effect on the sound?

Construction

Brief basic knowledge update. D.I. boxes always appear when an unbalanced signal, for example an electric bass, is not picked up via a microphone on the amplifier, but fed directly into the console. It is needed to extend the cable length to stage dimensions for a high-impedance signal, as in the Hz range there is a significant loss of sound from 6 meters of cable length and the next multicore is guaranteed not to be next to the bass box.

The advantages of a D.I. box are also complete independence from the sound of the amplifier and the security that no fool on stage will move the microphone on the loudspeaker. Disadvantage: also independence from the amplifier sound, as a high-quality bass amp such as the Classics from Ampeg on an all-tube basis, when well maintained, increases the value of the bass signal many times over. This is why ambitious FOHs usually work with 2 bass signals, D.I. and microphone.

So far, so good, but why does Rupert Neve go and serve a market that is already saturated? Well, because there is nothing that cannot be improved, especially if your name is Rupert Neve. The principle of the D.I. Box, the conversion of high-impedance to low-impedance signals, is also maintained in the Rupert Neve Designs RNDI. A classic TSR input for high-impedance signals loops through the same signal and can feed the signal into the input of the bass amplifier if required. An XLR socket on the back of the housing provides the low-impedance tap. Nothing new up to this point, but what is that inconspicuous mini switch labeled Input level on the front?

This is what makes the Rupert Neve Designs RNDI special. In contrast to almost all other D.I. boxes, the product can be switched not only into the instrument path, but also between the amplifier and the loudspeaker! Dear children, do not try this alone at home or whatever the warnings on TV said. Normally, apart from a solid loudspeaker cable, absolutely NOTHING has any place between the loudspeaker output and the speaker input, as the very high currents normally destroy all the electronics that do their job there. It is not for nothing that the thickest cables with the largest cross-sections are speaker cables.

The Rupert Neve Designs RNDI works with a headroom of +41.5 dBu and can therefore absorb power peaks of up to 1000 watts. This means that you can not only incorporate the amp's preamp or the tone control into the sound, most of the D.I. boxes built into the amp can do that too. No, with the Rupert Neve Designs RNDI we can capture the power amp compression that is so important in an all-tube amp with its soft saturation, which is a real highlight. Only the sound of the speaker is still the microphone's job and will always be. Why do we always talk about a bass amp? If we go into the guitar area, especially in the sound spectrum of a distorted electric guitar, the combination of speaker / microphone position plays an immense role in shaping the sound. You want to transmit a professional-sounding electric guitar without a microphone? Forget it!

Practice

When it comes to workmanship, one is inclined to use the overused toy term "indestructible" for the Rupert Neve Designs RNDI. The housing is more than just solid and would easily survive the tough everyday road use. However, the design and price suggest that it is more likely to be used in studios. The product receives the operating voltage for the Class A circuit via the phantom power of the XLR socket.

In terms of sound, the Rupert Neve Designs RNDI is impressive across the board. Thanks to the excellent Neve custom transformer, the product doesn't sound like one of those soulless D.I. boxes in mass production, but breathes a touch of character into every incoming signal. Not bloated but not too slim either, but with a very special touch of high mids that enrich the signal with additional liveliness.

Conclusion

With the Rupert Neve Designs RNDI, one of the biggest names in the audio industry has another top product on the market. With an extremely high headroom, the D.I. box can be used in areas that were previously not possible with a stand-alone D.I. box. In terms of sound and workmanship, it's the best you can get in this area at the moment!

Top marks!

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Additional Informations:

# The Evolution of Direct Injection (DI) Boxes

The Direct Injection (DI) box, a staple in audio recording and live sound reinforcement, has a rich history that dates back to the mid-20th century. This device, which plays a crucial role in balancing signals and eliminating unwanted noise, has evolved significantly over the years.

## The Birth of DI Boxes

The DI box was born out of necessity in the 1960s. As rock 'n' roll music gained popularity, bands started to play at larger venues, requiring more powerful amplification systems. However, these systems often picked up electrical interference, resulting in a noisy, distorted sound.

Engineers needed a solution to balance the unbalanced high-impedance signal from the guitar to the low-impedance input of the mixing console, while also reducing the likelihood of interference. The answer was the DI box.

## The Early Designs

The first DI boxes were passive devices, meaning they didn't require a power source. They used a transformer to convert the high-impedance signal from the instrument into a low-impedance signal suitable for the mixing console. These early DI boxes were simple, robust, and effective, but they had limitations, including signal loss and a limited frequency response.

## The Advent of Active DI Boxes

To overcome these limitations, the active DI box was introduced. Unlike its passive counterpart, an active DI box requires a power source. This allows it to have a higher input impedance, resulting in less signal loss and a broader frequency response. Active DI boxes quickly became popular in recording studios due to their superior sound quality.

## Modern DI Boxes

Today, DI boxes come in a variety of designs and offer a range of features. Some have multiple inputs for different instruments, while others have built-in equalizers to further shape the sound. There are even digital DI boxes that can model the sound of different types of amplifiers.

Despite these advancements, the core function of the DI box remains the same: to ensure that the signal from the instrument reaches the mixing console in the cleanest and most balanced form possible.

## Conclusion

From its humble beginnings in the 1960s to the sophisticated devices we see today, the DI box has been an integral part of audio engineering. As technology continues to advance, we can expect to see even more improvements and innovations in DI box design.

# The Technicalities of DI Boxes

## Passive DI Boxes

Passive DI boxes are simple in design, consisting of an input, an output, and a transformer. The transformer is the heart of the DI box, performing two critical tasks: matching impedance and balancing the signal.

Impedance matching is crucial because most musical instruments produce a high-impedance signal, while most professional audio equipment (like mixing consoles) prefer a low-impedance signal. The transformer in a passive DI box steps down the impedance, making the signal more suitable for long cable runs.

Balancing the signal involves converting an unbalanced signal (which is susceptible to noise) into a balanced signal (which is more resistant to noise). This is achieved by creating a copy of the signal, inverting it, and sending it along a second conductor. Any noise picked up along the way gets canceled out when the original and inverted signals are combined at the end of the cable run.

## Active DI Boxes

Active DI boxes, on the other hand, require an external power source, which can be a battery, phantom power from a mixing console, or an external power supply. The active DI box uses this power to operate a preamplifier, which boosts the signal from the instrument before it reaches the transformer.

The preamplifier in an active DI box has a high input impedance, which means it can accept a wider range of signal levels without distortion. This makes active DI boxes a better choice for instruments with low-level outputs, like electric guitars and basses.

## The Future of DI Boxes

As we look to the future, the humble DI box continues to evolve. Digital DI boxes are now available, offering features like onboard digital signal processing (DSP), which allows for more precise control over the sound. Some models even offer USB connectivity, making it easier than ever to integrate instruments with computer-based recording systems.

# The Impact of DI Boxes on the Music Industry

DI boxes have had a profound impact on the music industry. They have become an essential tool for both live performances and studio recordings, ensuring that the sound from the instruments is accurately captured and reproduced.

## Live Performances

In a live performance setting, DI boxes are used to connect instruments like keyboards and acoustic guitars directly to the PA system. This allows the sound engineer to control the volume and tone of each instrument independently, ensuring a balanced mix for the audience.

DI boxes also help to eliminate ground loop issues, which can cause a hum or buzz in the audio signal. By isolating the instrument from the PA system, DI boxes can effectively break the ground loop and eliminate this noise.

## Studio Recordings

In the studio, DI boxes are used to record instruments directly into the mixing console or audio interface. This provides a clean, uncolored sound that can be shaped and processed during the mixing stage.

For electric guitars and basses, recording through a DI box gives the engineer the option to re-amp the signal later. This involves playing the recorded DI signal back through an amplifier and miking up the amp to capture its sound. This technique allows the engineer to experiment with different amp settings and microphone placements without requiring the musician to perform the part again.

## The Unsung Hero

Despite their importance, DI boxes are often overlooked and taken for granted. They are the unsung heroes of the audio world, quietly doing their job in the background. But without them, the music we listen to would not sound the same.

Rupert Neve's D.I. Boxes have indeed made a significant impact on the music world. His designs, such as the RNDI Active Transformer Direct Interface, are highly regarded for their build quality and sound¹².

The RNDI's signature sound is the product of new custom Rupert Neve-designed transformers and class-A biased, discrete FET amplifiers². These elements contribute to the unique response of the RNDI, delivering a powerful and vibrant direct sound capable of reproducing the full harmonic depth of basses, guitars, acoustic instruments, and professional line level sources².

Musicians and engineers have reported a significant improvement in transient response, upper harmonic clarity, and low-end definition when upgrading to a Rupert Neve D.I. Box¹. This has led to a richer, deeper, and fuller sound that many in the industry have come to appreciate¹.

So, while it may be subjective to say whether Rupert Neve has "changed" the music world with his D.I. Boxes, it's clear that his designs have had a substantial influence and are highly valued in the industry. His commitment to quality and innovation continues to shape the sound of music production and live performances.