Filter sweeps: from a dark pluck to rhythmic movement

Open the sound by hand

The example is an original synthesized pluck, with a short attack, decaying harmonics and space between notes. Low-pass is selected, Filter is at 450 Hz, Q is 0.71 and the slope is 24 dB. Both modulation amounts are zero, so the dark starting sound comes from a fixed filter, not from a hidden envelope or a missing sidechain track.

While it plays, raise the knob labelled Filter from 450 Hz to about 2500 Hz. Listen to the front of each note: upper harmonics make the attack more apparent, while the low note itself was already passing. Return to 450 Hz to put that edge behind the sound again. A low-pass cutoff is not a volume control, although removing harmonics can reduce perceived loudness.

Try Q at 2 with the cutoff around 900 Hz. Listen for a more pointed emphasis near the filter edge, then return Q to 0.71. This resonance can give a sweep a recognizable vowel-like focus, but too much can make one pitch dominate. Keep monitoring quiet rather than increasing Q until it becomes uncomfortable.

Let the LFO move independently of the notes

Set Filter to 900 Hz, keep the 24 dB slope and choose Sine in the waveform selector. LFO Rate starts at 0.50 Hz: one cycle takes two seconds. Raise LFO Amount from 0 to about 15%. Listen across several notes for alternating darker and brighter attacks. The LFO follows its own cycle; it is not measuring how hard each note was played.

Compare 0.25 Hz with 1 Hz while leaving the amount unchanged. One makes a four-second contour, the other a one-second cycle. Faster is not necessarily more rhythmic: the cycle can line up with the notes or drift against their pattern. This panel uses Hz, not a tempo-synced note-division selector. Reduce LFO Amount to zero to hear the static cutoff again.

Or let each note’s level move the cutoff

With LFO Amount still at zero, set Filter back to 450 Hz and raise Env Amount to about +30%. Keep Attack at 10 ms and Release at 300 ms. The internal envelope follower responds to the incoming pluck, so positive movement opens the cutoff as the input becomes stronger. Compare the beginning and tail of each note rather than expecting the same result from every pitch.

Extend Release to 900 ms. The response should relax more slowly, potentially carrying brightness toward the following note. Return to 300 ms if that smears the intended gaps. Increase Attack toward 80 ms to delay the follower’s response to the transient, then restore 10 ms. Finally put Env Amount at zero for a direct reversal. These are follower timings, not a new volume envelope applied to the whole sound.

Know which controls can answer the problem

High-pass removes the lower range instead; Band-pass keeps a region around its centre. Notch rejects a region. Peaking and shelf types use Gain, but Gain is not an output trim for the Low-pass experiment. There is no dry/wet knob: the signal passes through the selected filter. The 12/24 dB switch also changes the resonance mapping, so compare slopes with modest Q rather than assuming identical resonance at the same number.

An external sidechain is useful only when a routed source is meant to drive the envelope follower. It is unnecessary here, and the example leaves it off. For your own material, replace the pluck with a local audio file and first repeat the static cutoff comparison. If the tone needs to stay consistent rather than move with time or level, an EQ may be the simpler choice.