FSVR v0.4.1

FSVR v0.4.1: the noise formant re-read off the hardware, and the snare traced to its carriers.

The noise band. rgwan recorded the fifteen demo songs with the effect section and the per-voice filter switched off, and Vokodrone's bass and drum parts on their own, so what is left between the unit and the engine is the tone generator alone. The drum's top octave was 3 dB bright on every hit, and following that down re-read the unvoiced operator: the band is two digital one-poles with different coefficients, and the wideband pedestal the last release could not model is the second pole's own floor. Both coefficients and the band's peak are now tables measured against the bandwidth register and the skirt, the same numbers off the 1 kHz and the 8 kHz takes, and the unvoiced output is averaged two samples at a time, a roll-off the fixed sines never show. Band shape on the four noise files went from 2.2 to 2.9 dB down to 0.5 to 1.5, and Vokodrone's top octave from +3.3 dB to -0.6. docs/noise.md, tools/fit_noise_band.py.

The snare. With the drum part isolated, the engine's snare reads 4 dB hot in the 100 to 200 Hz band its two sine carriers occupy, and muting every noise operator costs it half a decibel, so it is the FM, not the noise: the unit's modulation is deeper for the first six milliseconds. Three things behind that have never been measured, the velocity law at any sensitivity but 0, a decay to a level that is not silence, and a modulator on a modulator. tools/make_capture_tonal.py writes the four request files that do, the fourth being the demo's drum voice one hit at a time. docs/captures/capture_request_0922.md.

Also. tools/compare_isolated.py scores an isolated-part recording of a demo song hit by hit. The bass part's formants sit an octave out either side at fundamentals of 80 to 120 Hz, which is the formant window family at a note the capture set never played, and is open. tools/fs1r_demo_clip.py follows the tree reorganisation, and the song 1 and 2 clips in docs/media/ are rebuilt off this engine.

Against the effects-off take the engine sits 2.8 dB under the unit in the median octave band, flat across the bands, with four songs at zero.

Intel Macs. The macOS zip is universal now, arm64 and x86_64 in one binary, with a 10.13 deployment target. The previous release's was Apple silicon only, which is what issue #3 reported.