The Neunaber Technology Chroma Stereo Chorus is a chorus pedal that takes an unusual route to the effect. Instead of the audible LFO sweep of a traditional chorus, its default sound is produced by pitch-shifting two delayed signals by a fixed amount, one slightly sharp and one slightly flat1. The result is what RockBoard's product page describes as "a dual detune effect that achieves thick, liquid tones without modulation"2. Out of the box, MusicPlayers.com characterized it as a dual pitch transposition effect with regeneration3.
The pedal came out of Brian Neunaber's small California workshop, which launched the Stereo Chroma Chorus alongside a stereo Wet Reverb pedal in 2012, both selling direct for $22943. It sold for $229.00 as of the 2014 MusicPlayers.com review3.
How the dual detune design sounds
Because the two delayed signals are shifted by a fixed pitch amount rather than swept by an oscillator, the effect stays in place instead of wobbling. MusicPlayers.com's reviewer, Bruce Sokolovic, found this approach paid off in practice123:
"Neunaber's micro Pitch shift delivered a superior, more organic sound and less obvious change from the original tone" than traditional choruses' audible sweep, on clean tones into the front of an amp, in MusicPlayers.com's review3.
MusicRadar's Trevor Curwen noted that the Chroma still offers a lush version of the effect in a mono context, and that a standard chorus can be dialed in with the editor if you want the more familiar sound1. Bass Musician Magazine's Jake Wolf, testing it through a stereo 2x112 rig, praised "The Neunaber's high level of fidelity coupled with total mix/level control"4.
MusicPlayers.com describes the Chroma as a digital chorus pedal3, while RockBoard's product page lists its circuit type as analog2. The two descriptions conflict, and the maker's own documentation is the place to settle it.
The controls
There are three knobs on the face of the pedal, marked MIX, WIDTH, and a multi-function knob indicated by a triangle3. Bass Musician Magazine described the 3-knob layout as providing control over effect mix, depth, and regeneration4.
| Control | What it does |
|---|---|
| MIX | Sets the balance of effect against dry signal34 |
| WIDTH | Sets the width of the detune effect3 |
| Triangle knob | Multi-function control, including regeneration in the default mode34 |
Two 3.5mm expression pedal inputs can be used to control the mix and width controls, so you can move those parameters in real time from an expression pedal3.
The two mods and the NT Pedal Customizer
The pedal connects to a computer over USB, using the included cable, and can be customized through a Mac or Windows application downloadable from the company's website3. That software is the NT Pedal Customizer, and in the case of the Chroma Stereo Chorus there were two mods available at the time of the 2014 review3.
- Tone mod: removes the regeneration control and replaces it with a tone control. It is flat at 12:00, rolls off low frequencies counter-clockwise, and rolls off high frequencies clockwise3.
- Wet Reverb: the pedal can be completely reprogrammed as a Wet Reverb pedal, or vice versa, since the Chroma and the Wet share the same hardware platform4.
MusicRadar also mentions a Tone knob that can either attenuate top or bottom, and notes that a standard chorus can be dialed in with the editor1.
The pedal ships as a dual pitch transposition effect with regeneration, not as a conventional sweeping chorus. If you want the traditional chorus sound, you load it through the editor software13.
Power, bypass and connections
The Chroma is powered with a center negative power adapter, which is not included, and there is no battery option, so it is strictly a pedalboard-with-power-supply pedal3. It is a high-impedance pedal with a buffered bypass rather than true bypass3. It is a true stereo effects pedal, with two 1/4 inch inputs and a pair of 1/4 inch outputs, so it works in a full stereo rig3. Brian Neunaber provides a thorough manual for all of his pedals online, which also covers impedance and true bypass topics3.
Videos
Neunaber Audio
Tim Calloway
Starrman1970
Questions
Does the Neunaber Chroma Stereo Chorus run on a battery?
No. There is no battery option, so the pedal needs an external power supply. It runs on a center negative power adapter, and the adapter is not included with the pedal, so you need to supply your own.
Is the Chroma Stereo Chorus true stereo?
Yes. It is a true stereo effects pedal with two 1/4 inch inputs and a pair of 1/4 inch outputs, so it can sit in a full stereo rig with two amplifiers. Reviewers at Bass Musician Magazine tested it wired into a stereo 2x112 rig.
Is the Chroma Stereo Chorus true bypass?
No. It is a high-impedance pedal with a buffered bypass. Brian Neunaber also provides a thorough manual online that covers impedance and true bypass topics for players who want to understand how buffered bypass behaves in a signal chain.
What is the NT Pedal Customizer?
It is a free Mac and Windows application downloadable from the company's website. You connect the pedal with the included USB cable and use the software to load alternate versions of the effect, called mods, including a version that turns the pedal into a Wet Reverb.
Can I use an expression pedal with the Chroma Stereo Chorus?
Yes. The pedal has two 3.5mm expression pedal inputs, and they can be used to control the mix and width controls. That lets you sweep the effect in and out or change its width in real time while playing.
Sources (4)
- Neunaber Chroma Stereo Chorus review, MusicRadar, 2016-02-21
- Chroma Stereo Chorus by Neunaber, RockBoard PedalPedia, 2026
- Neunaber Technology Chroma Stereo Chorus, MusicPlayers.com, 2014-06-14
- Neunaber Stereo Chroma Chorus Pedal, Bass Musician Magazine, 2012-01-01
