The chain: oscillator → filter → amplifier
Press a key on an analog synth and three stages fire in order. An oscillator produces a deliberately bright, buzzy wave — a saw or a square — at the key’s pitch. A low-pass filter then removes some of that brightness, from the top down. Finally an amplifier, driven by an envelope, decides how the note’s loudness lives and dies. That is the whole architecture; everything on a panel is a knob on one of those three stages.
Why start bright and subtract?
A filter can only take harmonics away, never invent them. So the raw wave has to carry every harmonic the sound might ever need — which is why subtractive oscillators sound harsh alone. The sawtooth carries the full harmonic series; the square carries the odd harmonics. Keys Warrior’s own synth voices are built exactly this way: two slightly detuned oscillators into a swept low-pass, rendered honestly in your browser on every polysynth chord page.
The envelope is the instrument
Attack, decay, sustain, release — four numbers that turn one timbre into many instruments. Snap the attack to zero and clamp sustain and you get something percussive; slow the attack and a pad blooms. On the organ pages you can hear the degenerate case: an envelope pinned fully open for as long as the keys are held, which is why organ voicings never hide behind decay.
The numbers on this site’s own voices
Nothing here is hand-waved — the playback voices are ordinary subtractive patches with inspectable numbers. The polysynth voice runs two sawtooth oscillators detuned 12 cents apart into a low-pass whose base cutoff sits at 1400 Hz before the envelope opens it; the mono synth voice runs darker, its cutoff starting at 900 Hz with a harder resonance, which is why its lines bite the way mono basses do. The organ voice is the family’s oddball: two square waves an octave apart (the octave drawbar), filter envelope amount zero, sustain pinned at full — subtractive machinery imitating an instrument that never decays.
Every one of those numbers lives in one small profile table that CI checks against this paragraph — if the patches change, this guide has to change with them.
Where the filter earns its fame
The filter’s cutoff is rarely still: an envelope sweeps it downward through the note, so each key press starts bright and mellows. That moving cutoff — not the oscillator — is the signature of the analog sound. Open a polysynth chord page and listen for the first quarter second of each voice: that darkening is the filter envelope doing its one famous trick.