{
  "id": "spectrum_bands_chop",
  "name": "Spectrum Bands (CHOP)",
  "description": "Reproducible twin of create_spectrum: turns audio into N named per-band energy channels (band0..band15) on a Null CHOP you can bind any parameter to. An audiooscillatorCHOP (white noise) stands in so it previews offline; swap for Audio Device In / Audio File In for a live set. The chain is FFT -> resample to exactly N bins -> shuffle samples-to-channels -> rename -> sensitivity gain -> null. This is the CHOP-data companion to the visual audio_spectrum_bars recipe. Offline-validated against RecipeSchema; UNVERIFIED pending live cook-check.",
  "tags": ["audio-reactive", "spectrum", "chop", "analysis", "controls"],
  "difficulty": "intermediate",
  "td_version_min": "2022",
  "nodes": [
    {
      "name": "audioin",
      "type": "audiooscillatorCHOP",
      "parameters": { "wavetype": "whitenoise", "amp": 0.5 },
      "comment": "Synthetic full-spectrum source — swap for audiodeviceinCHOP / audiofileinCHOP live."
    },
    {
      "name": "spectrum_fft",
      "type": "audiospectrumCHOP",
      "parameters": { "outputmenu": "setmanually", "outlength": 256 },
      "comment": "FFT spectrum at a fixed length (resampled down to the band count next)."
    },
    {
      "name": "rebin",
      "type": "resampleCHOP",
      "parameters": {
        "relative": "abs",
        "start": 0,
        "end": 15,
        "startunit": "samples",
        "endunit": "samples",
        "interp": "linear"
      },
      "comment": "Reduce the FFT to exactly 16 bins (0..15) with linear averaging."
    },
    {
      "name": "split",
      "type": "shuffleCHOP",
      "parameters": { "method": "seqtochan" },
      "comment": "Transpose: 1 channel x 16 samples -> 16 channels x 1 sample."
    },
    {
      "name": "bands",
      "type": "renameCHOP",
      "parameters": { "renamefrom": "*", "renameto": "band[0-15]" },
      "comment": "Name the 16 channels band0..band15."
    },
    {
      "name": "sensitivity",
      "type": "mathCHOP",
      "parameters": { "gain": 1 },
      "comment": "Sensitivity gain over every band."
    },
    {
      "name": "spectrum",
      "type": "nullCHOP",
      "comment": "Stable bind point — bind parameters to op('spectrum')['band3'] etc."
    }
  ],
  "connections": [
    { "from": "audioin", "to": "spectrum_fft" },
    { "from": "spectrum_fft", "to": "rebin" },
    { "from": "rebin", "to": "split" },
    { "from": "split", "to": "bands" },
    { "from": "bands", "to": "sensitivity" },
    { "from": "sensitivity", "to": "spectrum" }
  ],
  "controls": [
    {
      "name": "Sensitivity",
      "type": "float",
      "min": 0,
      "max": 8,
      "default": 1,
      "bind_to": ["sensitivity.gain"]
    }
  ],
  "preview_description": "A CHOP utility, not an image: 16 live frequency-band channels (band0..band15) ready to drive any parameter, with a global sensitivity knob."
}