Formants

This to be a page about formant based waveforms.

formants.scm

formants.scm is a scheme used to help generate waveform filenames for the formant waveforms.

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sine-based formants

filename generator

All sinusoidal formants are in the folder formants_sine, and have the format formants_sine/formant_DD.wav, where "DD" is a number between 1 and 16 (inclusive).

The function formants-fname-sine will produce a filename, given a number.

There doesn't seem to be any formatted printing facilities built into s9 scheme, so I hacked in some zero leftpadding.

(define (formants-fname-sine num)
  (let
      ((mknum
        (lambda (n)
          (if (>= n 10)
              (number->string n)
              (begin
                (string-append "0" (number->string n)))))))
    (begin
      (string-append
       "formants_sine/formant_"
       (mknum num)
       ".wav"))))

observations

[2020-01-21 Tue 11:22] initial observations

I just got my XY pad instrument set up and loading these wavetables from SQLar. It sounds like they may be ordered based on number of harmonics or range of harmonics.

1 felt pretty subtractive saw-y, as does 2.

3 begin sounding vocal-like. I could move the XY pad oscillator and to make it say "WOW".

I jumped to 16, and it had a lot of high frequency content that could only be appreciated with really low sounds (MIDI 24), and audible aliasing occured in the upper frequencies.

A part of me thinks it would be worthwhile to build a morphing oscillator of 2-3 oscillators using Y for position. Would be a good way to compare wavetable spectrums relative to one another. I get the sense that the true magic of this formant wavetable set is from blending them together in this fashion.

non-sine based formants

filename generator

non-sine filenames are a bit more complicated than sine. In addition to the number, there's also a waveform time, which can be one of saw, square, or triangle.

(define (formants-fname-nonsine type num)
  (let
      ((mknum
        (lambda (n)
          (if (>= n 10)
              (number->string n)
              (begin
                (string-append "0" (number->string n)))))))
    (begin
      (string-append
       "formants_nonsine/formant_"
       type "_"
       (mknum num)
       ".wav"))))

observations

[2020-01-21 Tue 13:48]

initial thoughts.

like sine, higher the number, the brighter things tend to be. These are all very bright and alias very quickly.

The saws have a pretty massive sound for one oscillator. At 4, things sound very bright and high pitched, despite the NN being low.

The squares sound have more vocal qualities than the saw, which doesn't really surprise me considering how the square approximates the glottis. I was testing at 4.

The triangle unsurprisingly sounds most similar to the sinewaves. I wiggled the triangle around and it has more of a critter-like quality to it at 16. Sines are more subdued, have bottom.

sine at formant 2 sounds FM-y, while triangle sounds more reedy.

Formant Combinations

Load some combinations of formants into wavetables. Write some observations.

Combo0

Initially created: [2020-01-26 Sun 12:19]

This first combo is the first attempt at a waveform combo. Waveforms are arranged in ascending order, which also correlates with more high-frequency spectral content.

I was hoping these waveforms morphing together would sound more "talky". It's more of a resonant sound, kind of like a resonant lowpass filter, but with a bit more crunch at the upper-end. At certain ranges, it sounds a bit like a male "eh" sound, but that's as close as it gets.

The waveforms I chose are not equidistance: 2, 4, 12. When strung together, it gives subtle non-linear response while morphing. 2 was chosen to get a waveform with some teeth. 4 has a bit more. 12 has upper frequency content, but not too much to overdo it.

When I wiggle the stylus in the upper left-hand corner of the XY instrument (high frequency, mostly upper waveform), there's a bit of helpless tiny animal shriek you can get. It's annoying, but there's a place for it.

(define (fmt-combo0)
  (lwt (fmtsin 2) 0)
  (lwt (fmtsin 4) 1)
  (lwt (fmtsin 12) 2))