The Russian-made Polivoks duophonic, analog synthesizer is renowned in esoteric synth circles for its austere aesthetics and grimy synth growl, which derives from its unique and characterful voltage-controlled filter. Now, Latvian Eurorack pioneers, Erica Synths, have emancipated the Polivoks filter and placed it into the Acidbox III tabletop module, with all the Soviet-era swagger intact. Combining a switchable lowpass/bandpass resonant filter, LFO, envelope follower, and divider, Acidbox III injects life and movement into any signal that passes through it. With left-right inputs and outputs, it can process stereo signals or add instant width and dimension to a mono source. And if you want to get a little gnarly, drive the input for intense grit and saturation. At first blush, AcidBox III seems like it’s just for synth heads. But, Sweetwater’s guitarists and bassists are equally excited about its tonal possibilities and dropping it in their signal chains. Want to take your sound design to the next level? Acidbox III is engaging, idiosyncratic, and could be just what you need.
Acidbox III is super intuitive, featuring a selectable lowpass or bandpass cutoff knob that simultaneously affects both Polivoks VCF channels, which have intentional, minute variations for interesting harmonic interplay. Underneath the cutoff knob are resonance, mod level, and input level controls. With a little twisting, you can create subtle to ear-splitting sweeps and layers in complex, brain-melting modulations. The unit also includes a fully-featured LFO section — with waveshape selection, speed, shape, depth, and divider/multiplier controls — and an envelope follower with rate and depth controls. So ghostly howls or weird robotic bleeps and bloops are no problem. And a configurable control input gives you the option to bypass the unit via footswitch or use an expression pedal to control cutoff or LFO synchronization. Extremely flexible by design, Acidbox III excels in studio environments and live performance settings.


Prized for their weighty tones and hypnotic drones, Erica Synths Eurorack modules fortify your sonic arsenal with unique sounds that work brilliantly cross-genre. The company was founded by Girts Ozolins, who started out designing DIY kits and components for designers and synthesists. Today, Sweetwater is delighted to offer you Erica Synths’ acclaimed line of Eurorack modules and systems that have captured the imaginations of synthesists worldwide with their distinctively punchy, aggressive sound and innovative features.
| Specification | Detail |
|---|---|
| Type | Desktop Filter/Drive Effects |
| Analog/Digital | Analog |
| LFO | 1 x LFO, 8 x Waveforms |
| Filter | Polivoks Stereo Lowpass/Bandpass VCF |
| Analog Inputs | 2 x 1/4" (Hi-Z/line) |
| Analog Outputs | 2 x 1/4" (L/R) |
| Other I/O | 1 x 1/4" (configurable control in) |
| Power Supply | 12V DC power supply (sold separately) |
| Height | 2.16" |
| Width | 7.28" |
| Depth | 5.51" |
| Weight | 1.5 lbs. |
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