 As every tone consists of an almost completely independent synthesizer voice a patch could be considered a layer of up to 4 different synthesizers.In single mode the JD-800 plays one patch at a time, but in multi mode it is possible to play 5 different patches, over MIDI, plus an extra "special" patch.The special patch has different waveforms assigned to the 61 different keys on the keyboard, so is used for drums and percussion sounds.