AUD · Audio tools

Vowel Filter

Continue editing Open in workflow
Often followed by + Compressor + Reverb + Echo

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Settings are written to the URL as you change them. Nothing differs from the defaults yet.

Oxyd To put the result on a track with other audio, Oxyd is a multitrack editor with the same effects. Open Oxyd

Shape a sound with a vowel. Four band-pass filters sit on the formant frequencies of a sung A, E, I, O or U, and the signal passes through all four at once, so a pad, a lead, a loop or a voice takes on the vowel’s colour. The formant table is the tenor set from the Csound manual, which is the one behind every “vowel mode” on a filter plug-in.

Vowel and resonance

Vowel is a morph position: 0 is A, then E, I, O and U at the quarter points, and anywhere between them interpolates the formant frequencies, levels and bandwidths of the two neighbours. Resonance scales the bandwidth of all four formants together. Above 100 percent the vowel sharpens and starts to ring; below it the filter opens into a broad colour.

Moving the vowel

LFO rate and LFO depth sweep the morph on a sine; a slow rate at full depth is the classic talking-pad effect. Envelope lets the input level push the morph as well, measured against the running level of the material rather than a fixed point, so the same setting works on a quiet file and a loud one. The two add, and the morph wraps around, so a sweep cycles A, E, I, O, U, A rather than parking on an end.

Mix

The wet path carries only four narrow bands, so it is raised to sit near the dry signal at an even mix. At 100 percent only the vowel is heard; around 50 the source keeps its body and gains the vowel on top.

In the audio workflow

The filter is a workflow step, so it chains before a reverb or a delay, which is where it belongs: the vowel is a colour, the space comes after it.

Frequently Asked Questions

Four resonant band-pass filters sit on the first four formants of a sung vowel, so whatever passes through sounds as if a mouth were shaping it. The Vowel control morphs between A, E, I, O and U; the LFO and the envelope move it for you.

The formant shifter moves a voice's own resonances up or down and leaves the pitch alone. The vowel filter imposes a chosen vowel's resonances on any source, a synth pad, a drum loop or a guitar, which have no formants of their own.

It pushes the vowel along with the input level, measured against the running level of the material rather than full scale, so an attack opens the vowel the way an auto-wah opens its filter. At 0 the level has no say.

The morph wraps around, so a sweep moves through all five vowels in a cycle instead of bouncing off the ends. With the LFO depth at 0 the Vowel setting is exactly where the filter sits.

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