Analog synth routing: blend a direct chord with a softer layer

Analog has two oscillator sources, two filter paths and two amplifiers. Each filter and amplifier has its own envelope. The important detail is that oscillator routing is adjustable: oscillator 1 does not have to stay with filter 1. The Bal controls choose filter destinations; the Pan controls place amplifier outputs in the stereo image.

Hear the two roles before touching the routing

The original MIDI chord sequence below starts with both oscillators on. The first is a saw, routed to a darker 700 Hz low-pass path with a quick amplifier attack. The second is a triangle through a more open 4500 Hz path, with a 350 ms amplifier attack and a longer release. Gentle left/right placement helps distinguish them without putting either completely in one ear.

Turn Osc 2 Off in its oscillator section and replay a chord. Listen to the relatively immediate, darker first layer. Turn Osc 2 On, then Osc 1 Off to hear the softer arrival alone. Finally restore both to On. A slow attack may be interrupted by shorter notes: judge the blend on notes that last long enough for the second path to emerge.

In Amp 2, reduce its A value from 350 to 15 ms. Both layers now arrive more directly. The chord may feel firmer but lose the sense of unfolding. Return A to 350 ms; if that entrance is too late for the rhythm, try an intermediate 100 ms. These envelope boxes are labelled A, D, S and R, meaning attack, decay, sustain and release.

Bal 1 is not Pan 1

For the routing experiment, turn Osc 2 Off again. Move Bal 1 from 0% toward 100%. At zero, oscillator 1 feeds filter 1; at 100%, it feeds filter 2. Halfway sends it to both. Listen for a change in brightness, entrance and stereo position, because the signal is now encountering the second filter and amplifier settings.

Leave Amp 2 active while doing this. Switching off Osc 2 removes that oscillator source, not the entire second processing path. If you instead lower Amp 2 to zero, material routed to filter 2 will not reach the output through that amplifier. Return Bal 1 to 0% and Osc 2 to On to recover the example.

Pan 1 and Pan 2 operate after their respective filters and amplifier envelopes. Their centre position is 50%. Set both to 50% to judge whether the layers still complement each other without stereo separation, then restore 35% and 65% if useful. Panning can reveal roles; it should not disguise two layers that are too dense when combined.

Separate the brightness contour from the volume contour

Both F1 Env and F2 Env start at zero so the first comparison is uncomplicated. Try F1 Env at +2 oct with Filter 1 D at 200 ms and S at 0%. Keep its A short. The first layer now begins brighter and settles toward its base F1 Freq, while Amp 1 can continue holding the chord. Set F1 Env back to zero to remove that movement without shortening the note.

LP, HP and BP select low-pass, high-pass and band-pass filtering. F1 Key and F2 Key make cutoff follow played pitch; the example sets both to zero for a fixed reference. A useful bass setting may become dull higher up the keyboard, so revisit key tracking before adding a blanket treble boost. Filter resonance is independent of amplifier level: turn down Volume if a resonant setting becomes unexpectedly prominent.

Choose complexity that has an audible purpose

Det 2 is only 7 cents here, enough to introduce beating without writing a second harmony. PW changes the Rect waveform, not every waveform equally. Sub adds a square component an octave lower; Noise has its own routing balance. None is necessary for this chord. Add one only if you can describe what the arrangement is missing.

The example uses the analytic oscillator path with Live Waves Off. Its names and layout do not establish equivalence to another synth or physical circuit. Think of the implemented routing as two parallel filter/amplifier destinations, not a freely configurable modular patch or a serial filter chain. That distinction keeps both sound design and troubleshooting much easier to follow.