STUMM is a six-channel bank of high-fidelity audio mutes with grouping functionality. Each individual mute switch offers toggled (switch up) and momentary (switch down) click-less muting, and is also assignable to belong to group A, B or neither group. Signal is passed through each channel's VCA when the switch is either up or down - the channel is muted in the middle position.

Each channel's input is passed through an DC-coupled discrete VCA, where each VCA is controlled by a discrete attack/release generator triggered by the mute switch. By default, the envelope times are set to be very fast to achieve click-less muting. LEDs also indicate when audio is being passed through the VCAs (i.e. not muted). Due to each VCA being DC-coupled, control voltages can also be passed through STUMM, offering even further flexibility for live performance.

Expect several expander modules to be announced in the near future. These will allow for variable fade up and down times, voltage control of each VCA, and slope outputs from each mute channel.