Spectral Analyzer with Metadata outputs (Freq, Rank/Ratio, Amplitude, Phase)?

Triggered by another thread on Spectral Processing (and a long time feature wish):

I don’t know of any Spectral Analyzer in VCV Rack that can output per harmonic/partial metadata for an audio input signal:

  • frequency (generally the root harmonic/partial frequency)
  • harmonic/partial rank/ratio (relative to root harmonic/partial)
  • amplitude (per sample or slewed follower)
  • phase (relative to root harmonic/partial)

So, not filtered signal (band) output(s), as offered by various modules, but per harmonic/partial metadata output(s).

Harmonics/partials are relative to the ‘note’ (generally the root harmonic/partial frequency). The module could derive the note/frequency from the audio input signal, but this could be overrided by connecting a V/Oct source to a dedicated V/Oct input.

Such per harmonic/partial metadata outputs could be used for many interesting things in the additive/spectral (re)synthesis/processing domain.

For example:

  • modulating (external) oscillator (sine or other) frequency and/or amplitude (and/or phase)
  • modulating (external) filter (or EQ band or mode or resonator…) frequency and/or amplitude

Such a module could be implemented as:

  • single harmonic/partial, with outputs for metadata for just one selectable harmonic/partial from an audio input signal.
  • single harmonic/partial + expander(s) to add harmonics/partials to chain upto 16 harmonics/partials (optionally merged into a polyphonic output).
  • fixed max. 16 harmonics/partials metadata outputs (optionally merged into a polyphonic output).
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