The Neunaber Chroma Stereo Chorus is a stereo chorus pedal from Neunaber Technology, a small California workshop run by Brian Neunaber1. What sets it apart from most chorus pedals is what it does out of the box: instead of sweeping a delayed signal with an oscillator, it pitch-shifts delayed signals by a fixed amount, one slightly sharp and one slightly flat23. Because nothing is swept, you hear the subtle, natural beat frequencies between the multiple voices rather than the moving warble of a conventional chorus4.
How it works
The default chorus is built by pitch transposition: two delayed copies of your signal are shifted in pitch by a fixed amount, one up and one down, and mixed back with the dry signal2. RockBoard describes the result as a dual detune effect that achieves thick, liquid tones without modulation4. This is closer in spirit to a detune or tri-chorus effect than to a classic modulated chorus: the pitch offset is constant, so the motion you hear comes from the beating between the detuned voices rather than from a rate control4.
A second mode is available through the editor. Loaded with the "modulation" mod, the pedal becomes a traditional dual chorus, with the knobs controlling chorus level, modulation rate and modulation depth3. MusicRadar's reviewer Trevor Curwen notes that a standard chorus can be dialed in with the editor2.
The controls and the editor
There are three knobs on the face of the pedal, marked MIX, WIDTH and a multi-function knob indicated by a triangle3. What the triangle knob does depends on the loaded mod: in the Chroma mode the maker's manual describes it as controlling chorus signal regeneration or tone5, while in the modulation mod it handles one of the chorus parameters3.
| Control | What it does |
|---|---|
| MIX | Sets the effect mix31 |
| WIDTH | Controls the amount of the pitch transposition2 |
| Δ (triangle) | Multi-function: chorus signal regeneration or tone in Chroma mode53 |
Bass Musician Magazine's reviewer found the three-knob layout gives "great control over effect mix, depth, and regeneration"1.
The pedal is reprogrammable. It connects by the included USB cable to Neunaber's proprietary Pedal Customizer software, a Mac or Windows application downloadable from the company's website, which loads different effect "mods" into the pedal13. Two mods were available for the Chroma Stereo Chorus as of the 2014 review: the default dual pitch transposition effect with regeneration, and the traditional dual chorus3.
Stereo operation
The Chroma is a true stereo effects pedal, with two 1/4" inputs and a pair of 1/4" outputs, so a stereo rig gets independent processing per channel3. Reviewers consistently singled this out as where the pedal performs best. MusicPlayers.com's Bruce Sokolovic wrote:
"This chorus pedal truly shines in stereo! The sound was wide, vibrant and three-dimensional."3
Bass Musician Magazine's Jake Wolf ran the pedal through a stereo rig and reported "The Neunaber's high level of fidelity coupled with total mix/level control"1.
The pedal is powered with a center negative power adapter, which is not included, so plan on supplying your own 9V supply34.
What reviewers said
Naming and versions
The pedal appears under slightly different names across its life: the "Stereo Chroma Chorus" in the 2012 launch coverage1, the "Chroma Stereo Chorus" in later reviews3, and "Chroma Stereo Chorus v1" in the current manual hosted at Quilter Labs54. These are the same three-knob stereo chorus pedal from Neunaber Technology. Neunaber later expanded on the chorus concept with the Inspire Tri-Chorus Plus, a stereo chorus pedal from the same maker.
Videos
Neunaber Audio
Tim Calloway
Antoine Michaud
Questions
Is the Neunaber Chroma Stereo Chorus analog or digital?
The Chroma Chorus is a chorus pedal from RockBoard. Its default effect pitch-shifts two delayed signals by a fixed amount, which is consistent with a digital design, and MusicPlayers.com's 2014 review describes it as a digital chorus pedal. RockBoard's own product page, however, lists the circuit type as analog, so the two published descriptions conflict.
What power does the Neunaber Chroma Stereo Chorus use?
It runs on a 9V DC center negative power supply with a current draw of 100mA. The adapter is not included with the pedal, so you need to supply your own. At 100mA it draws more than many small analog chorus pedals, which is worth noting if you run a compact power brick.
Does the Chroma work in 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 each channel is processed independently. Reviewers found it particularly effective in stereo, describing the sound as wide, vibrant and three-dimensional.
Can the Chroma produce a standard chorus sound?
Yes. Its default mode is a dual detune effect with no modulation, but a second mod loaded through the Pedal Customizer software turns it into a traditional dual chorus with controls for chorus level, modulation rate and modulation depth. MusicRadar's reviewer also notes a standard chorus can be dialed in with the editor.
Is the Stereo Chroma Chorus the same pedal as the Chroma Stereo Chorus?
They are the same pedal under different name orderings. Bass Musician Magazine reviewed it in 2012 as the Stereo Chroma Chorus, MusicPlayers.com in 2014 as the Chroma Stereo Chorus, and the current manual hosted at Quilter Labs titles it Chroma Stereo Chorus v1. All describe the same three-knob stereo chorus from Neunaber.
Sources (5)
- Neunaber Stereo Chroma Chorus Pedal, Bass Musician Magazine, 2012-01-01
- Neunaber Chroma Stereo Chorus review, MusicRadar, 2016-02-21
- Neunaber Technology Chroma Stereo Chorus, MusicPlayers.com, 2014-06-14
- Chroma Stereo Chorus by Neunaber, RockBoard PedalPedia, 2026
- Stereo Effect Pedal (v1) User Guide, Quilter Labs
