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Vance Ingalls
65629692d0
Finds the bands a voice occupies so a music bed can be dipped there, letting the voice sit in front without ducking the whole track. Carve is a relationship between two tracks rather than an effect on one, so it stays out of the FX chain. What it emits is an ordinary chain of peaking filters, so a carve composes with whatever else is on the track and needs no separate rendering path. Selection is weighted toward intelligibility rather than raw voice energy. Ranking purely by power lands on the fundamental almost every time, because that is where a voice is loudest — but the masking that actually hurts a voiceover happens higher up, and dipping 160 Hz mostly just thins the bed. The bias is a control, not a constant: at 0 it follows raw energy, at 1 it weights toward 1-3 kHz. Ranking happens in dB, which matters more than it looks. Speech spreads 20-30 dB across these bands — it falls off roughly 6 dB per octave above the fundamental — so a weighting has to be on that scale to move anything at all. A multiplicative weight of `1 - bias + bias * shaped` is bounded below by `1 - bias`, capping its influence at 10*log10(1/(1 - bias)): 5.2 dB at the 0.7 default, 3 dB at 0.5. That is no influence against a real voice — every bias short of ~0.95 would rank exactly like bias 0 and carve the fundamental, the outcome the bias exists to prevent, while looking decisive against a fixture whose bands sit 2 dB apart. So the bias is a dB penalty, zero at 2 kHz and worth up to 30 dB at full strength, and relative cut depths come from a dB difference rather than a ratio of weighted linear powers. The bias reweights ranking without overriding the spectrum — a band the voice has no energy in is not worth carving, and scores -Infinity rather than competing — so a strongly low-pitched voice can still select low at full bias. What the tests hold is that biasing never selects lower than the unbiased ranking, that the DEFAULT bias reaches the presence region on a voice with a realistic tilt, and that bias 0 still follows raw power exactly. Includes a radix-2 FFT rather than a dependency; one Welch-style averaged spectrum over third-octave bands does not justify pulling in a DSP library.