The very very basics of classic analog 'subtractive' synths are that you have a wave generator (oscillator), usually these generate Sine, Square, Triangle or Sa

The very very basics of classic analog 'subtractive' synths are that you have a wave generator (oscillator), usually these generate Sine, Square, Triangle or Saw waves. You then pass that through a Low Pass Filter. The Low Pass Filter has a cutoff set, frequencies lower than the cutoff pass through unaffected, higher than the cutoff gets attenuated and monkeyed around with. Thats the classic synth sound basically. But there's loads of other stuff on top of that - multiple oscillators slightly detuned from each other, attack/decay/sustain/release of the volume, using an LFO (low frequency osciallator) to modify the cutoff of the low pass filter, etc etc If you play with a wave generator and a Low Pass Filter and try the different wave types (Sine, Saw, Triangle, Square) you will quickly recognise all kinds of synths sounds that you already know, e.g. you'll recognise the distinctive sound of a square wave bassline. Or the pure sound of a sine wave (think classic Doctor Who theme) In Propellerheads Reason, there's a device called 'Subtractor' which is basically a classic synth. This page explaining how the use the Subtractor covers a lot of the different things that analog synths do. https://www.reasonexperts.com/subtractor-basics.html https://www.reasonexperts.com/subtractor-basics.html