Chapter 2
Filters
The tone knob that became an instrument.
After this chapter: “I can shape a note with cutoff and resonance.”
2.1
Cutoff: where the carving starts
A low-pass filter lets low frequencies through and removes highs above the cutoff. Turn cutoff down and a saw goes from bright to muffled to a dark thump. Turn it up and everything comes back.
Other types exist: high-pass removes lows (great for thin hats and airy pads), band-pass keeps only a slice in the middle (telephone, wah), and notch removes a slice.
2.2
Resonance: the squelch
Resonance (or emphasis, or Q) boosts frequencies right at the cutoff point. A little adds bite. A lot adds a whistling peak that sings as you sweep — the squelch at the heart of acid house.
Filter slope describes how steeply frequencies above cutoff fade: 12 dB per octave is gentle, 24 dB per octave (the classic 4-pole ladder) is steep and dramatic.
On real gear · Hydrasynth Deluxe
Filter 1 offers a menu of models from ladder-style low-pass to vowel and comb types; Filter 2 morphs smoothly between low-pass, band-pass and high-pass.
Experiment #2-1
Resonance
Make the filter sing at its cutoff point.
- 1.In the figure, set RESONANCE to 0% and move CUTOFF left and right.
- 2.Raise RESONANCE to about 80% and sweep again. Watch the peak.
- 3.In the Signal Path Explorer, load ACID SQUELCH and play low notes.
You should hear…
Without resonance, a smooth darkening. With it, a whistling peak that follows the knob — the acid squelch.
Doesn’t sound right?
Peak too harsh? Back RESO off a little or lower LEVEL; high resonance gets loud.
- TB-3
- Hydrasynth Deluxe
- SH-01A
More recipes from this chapter
Full interactive panels with the same Manual & Panel layout — steps stay readable as text.
Check yourselfYou want an 808 hat to sound thinner. Which filter type helps?Reveal
A high-pass filter — it removes the low body and leaves the sizzle.
Next on the path
Stamp the recipes above, then either keep reading or step onto the gear route when you want a specific instrument’s panel language.