BiSynth is a virtual analog synthesizer. The audio output is produced by a pair of computed or sampled waveforms modulated by a note envelope.
Choose between scrolling 5 octave classic and Janko keyboards with both hammered and slurred key activation, as well as a scrollable 5 octave Theremin pad with each keyboard.
The left and right output channels of the iPhone may be given different waveforms from a selection available on the settings screen. The note envelopes are the same on each channel, and are computed from attack, decay, sustain, and release settings, also on the settings screen.
A frequency difference between left and right channels can be set in Hertz (cycles per second) or halfsteps (the smallest musical interval on the piano). Halfstep differences are useful for exploring harmonious and not so harmonious intervals. The differences in Hertz can generate vibrato of different frequences, as well as a kind of poor mans surround sound simulation.
A variable cutoff, resonant filter allows the user to adjust the sound of each pair of waveforms, and a pan control allows the left and right channels to be mixed in different proportions.
When you fiddle around with the settings and produce a sound that you like; you can save it in a database of presets.