Doppio is powered by six delay-lines that can be turned on or off. These are divided into two banks of three, with a center knob to control the bias of the output.
Each delay line has useful parameters like feedback, decay, length, L/R (pan), as well as a hybrid knob that can apply a low-pass or a high-pass filter to the input.
Reverse, Shape and Beat Sync can be enabled for any or all delay lines to alter the output.
Reverse module - incoming audio is stored in a buffer of variable length and fed backwards into a delay line. If the Reverse length is short enough, distortion effects are created, while a larger buffer will produce a wobbly or bouncy effect.
Shape module - an oscillating effect that is sped up or slowed down, depending on the value of that line’s Length parameter.
Beat Sync - each delay line can be synced to the song tempo with common time signatures. A complex rhythm can be achieved by mixing lines with synced and unsynced delay lengths.
Doppio comes with over 120 patches separated into these categories: Reverb, Chorus, FX, Rhythm, and Synced.