Even playing a single note, having your oscillators a couple cents out of tune with each other contributes to a warm sound! Old polyphonic synths like the vene

Even playing a single note, having your oscillators a couple cents out of tune with each other contributes to a warm sound! Old polyphonic synths like the venerable Oberheim OB-Xa would have their voices go slightly out of tune as the instrument warmes up. It's subtle, but once you hear it you start to notice the color it adds