Build a clear synth bass with cutoff and envelope

Follow a note from its edge to its body

Play the generated MIDI bass phrase below. These are original teaching notes driving Synth, not a sampled bass performance. Osc 1 is Saw, Osc Mix is 0%, and Cutoff is 350 Hz. The saw supplies harmonics; the low-pass filter reduces the higher ones. F. Env at +3 oct briefly opens that filter as each note begins, so the sound has more edge at the front than its resting cutoff suggests.

Turn F. Env to 0 oct without moving Cutoff. Listen for the attack becoming darker, while the MIDI rhythm stays the same. Restore +3 oct and replay the phrase. If the two settings seem mainly different in loudness, turn down Volume for the brighter one before deciding which articulation you prefer.

An octave here describes a frequency ratio, not a transposed note. At the envelope peak, +3 oct can raise 350 Hz toward 2800 Hz. That does not change the pitch played by the oscillators. It changes how many of their harmonics pass. A brighter bass can remain intelligible on small speakers, but excessive edge may compete with other attacks in the arrangement.

One envelope means two consequences

Attack, Decay, Sustain and Release describe the level contour. Attack rises from silence. Decay moves from the peak toward Sustain, which is a held level rather than a duration. Release begins when the MIDI note ends. With F. Env nonzero, this same contour also moves the cutoff. There is no independent filter envelope hidden elsewhere in this panel.

1. Keep F. Env at +3 oct and extend Decay from 180 to 600 ms. Listen for both the louder front and the brighter region lasting longer. Return to 180 ms if the phrase loses its short, separated accents.
2. Raise Sustain from 25% to 70%. The held note becomes stronger, but the filter also stays farther open. Return to 25% and compare again; Sustain is not merely a bass-volume adjustment.
3. Increase Release from 120 to 500 ms. Hear how the space after each note fills in. Restore 120 ms if successive notes overlap too much. Release cannot bring back a note that has already decayed to an inaudible level.

A slower Attack can soften a bass part, but on short notes it can also prevent the sound from reaching its intended peak. Start around 5–20 ms rather than assuming a pad-length fade-in will simply make the same bass smoother. If you need a long, steady amplitude contour with a fast filter pluck, Drift or Analog gives those jobs separate envelope controls.

Add another oscillator only after the rhythm works

Both waveform selectors offer Saw, Square, Triangle and Sine. Saw and Square provide stronger upper-harmonic material for the filter to shape; Sine leaves much less to remove. To compare waveforms, temporarily set F. Env to zero and raise Cutoff to about 5000 Hz. Return to the starting settings afterward.

With both oscillators set to Saw, bring Osc Mix to 50% and set Detune to about 7 ct. Detune changes oscillator 2 in cents: 100 cents is one semitone. Listen for slow beating between the oscillators, then restore Detune to zero and Osc Mix to 0%. Detune cannot be heard while oscillator 2 is absent from the mix. This adds interference and motion, not independent stereo voices; the engine sends the same synthesis output to left and right.

Keep Res modest while learning the cutoff. It emphasizes the filter region and can alter the apparent body of the bass. There is no onboard LFO, glide control or selectable filter topology here. That limited surface is useful: get the note contour, harmonic balance and final Volume right before adding effects or moving to a more elaborate instrument.