Filters
A low-pass, high-pass, or band-pass turns down part of the spectrum. Cutoff is where that starts, in Hz. Resonance emphasizes the cutoff itself.
A filter turns part of the spectrum down. Cutoff is the frequency where that starts, in Hz. Resonance, sometimes labelled Q, boosts a narrow band right at the cutoff, which is what you hear moving when the cutoff sweeps.
| Low-pass | Keeps what is below the cutoff. Moving it down takes a bright sound toward a muffled one. Most synth patches start here. |
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| High-pass | Keeps what is above the cutoff. The channel version clears rumble or mud before the compressor. |
| Band-pass | Keeps a strip around the cutoff and turns both sides down. |
An envelope or an LFO moving the cutoff is a filter sweep inside the instrument. The same motion drawn on the timeline is automation.
Resonance does not move the cutoff. A little makes the corner obvious. More adds a ringing edge, and at high values that edge can take over the tone. If a sweep is hard to hear, the resonance may be too low, or the oscillator may have few harmonics up there. A sine has none for the filter to reveal.
The HP/LP control in a channel’s gain section is this tool, placed before the compressor. The channel EQ is narrower: it boosts or cuts one band and can leave the rest of the spectrum alone.