A UGen to find the percentile of a signal's magnitude spectrum. Given an FFT
chain this calculates the cumulative distribution of the frequency spectrum, and
outputs the frequency value which corresponds to the desired percentile. For
example, to find the frequency at which 90% of the spectral energy lies below
that frequency, you want the 90-percentile, which means the value of percent
should be 0.9. The 90-percentile or 95-percentile is often used as a measure of
spectral roll-off.
Note that despite running at control-rate, the output remains constant for each FFT frame. E.g. with an FFT size of 1024 and 50% overlap, a new measure is generated every 512 audio frames, or (at control block size 64) every 8 control blocks.
- Value Params
- chain
the fft signal (buffer) to analyze
- interp
specifies whether interpolation should be used to try and make the percentile frequency estimate more accurate, at the cost of a little higher CPU usage. Set it to 1 to enable this.
- percent
the percentage between 0.0 (0%) and 1.0 (100%)
- Companion
- object