The number of different timbres (instruments) a synthesizer can play at a time. Some synthesizers are polyphonic but only monotimbral - ie they can play several sounds but only in the same instrument....
Rogue
The Rogue, a "Miniaturized, cost-cutting successor" to the Moog Prodigy, is a 2-VCO,
monophonic synthesizer with a 2-1/2 octave, 32-note (F-C) keyboard. Both VCOs are
tunable to three octaves by a common switch. In addition, VCO2 is tunable via a knob to
anywhere between a half-step below to an octave above VCO1. There is also a single
switch that selects the waveform for both VCOs. A three position switch syncs VCO2 to
VCO1. It can be hard synced or contoured synced, where the amount that VCO2 is
synced to VCO1 is controlled by the envelope generator. The mixer section allows both
VCOs and the noise generator to be mixed together, with a slider controlling each level.
The mixer can be pushed to overdrive (distort) the waveforms. The filter section
features variable keyboard tracking controlled by a knob, and sliders for the cutoff
frequency, emphasis (resonance), and envelope amount. It also has "the pitch and mod
wheels up above the keyboard, not to the left of it, along with a fine tune knob and a
glide (portamento) knob." The Rogue has a single envelope generator for attack and
decay, that switches to activate the sustain mode. There is also a switch that selects
how the envelope affects the VCA. It can be set for either contour, keyed, or bypass
(which was a simple organ-style gate).