spec: "1.0"
id: "com.grooveforge.eq"
name: "4-Band EQ"
version: "1.0.0"
type: effect

# Four-band parametric equaliser using biquad IIR filters.
# Bands: low-shelf, two peaking mid bands, high-shelf.
# Gain range +-12 dB per band. Cut or boost to shape the timbre of any signal.

parameters:
  # Low shelf — boosts/cuts bass below the corner frequency.
  - id: low_freq
    paramId: 0
    name: "Low Hz"
    min: 40.0
    max: 400.0
    default: 100.0
    unit: "Hz"
  - id: low_gain
    paramId: 1
    name: "Low"
    min: -12.0
    max: 12.0
    default: 0.0
    unit: "dB"

  # Low-mid peaking band.
  - id: lmid_freq
    paramId: 2
    name: "LM Hz"
    min: 200.0
    max: 2000.0
    default: 500.0
    unit: "Hz"
  - id: lmid_q
    paramId: 3
    name: "LM Q"
    min: 0.3
    max: 8.0
    default: 1.0
  - id: lmid_gain
    paramId: 4
    name: "LM"
    min: -12.0
    max: 12.0
    default: 0.0
    unit: "dB"

  # High-mid peaking band.
  - id: hmid_freq
    paramId: 5
    name: "HM Hz"
    min: 800.0
    max: 8000.0
    default: 2500.0
    unit: "Hz"
  - id: hmid_q
    paramId: 6
    name: "HM Q"
    min: 0.3
    max: 8.0
    default: 1.0
  - id: hmid_gain
    paramId: 7
    name: "HM"
    min: -12.0
    max: 12.0
    default: 0.0
    unit: "dB"

  # High shelf — boosts/cuts treble above the corner frequency.
  - id: high_freq
    paramId: 8
    name: "Hi Hz"
    min: 2000.0
    max: 16000.0
    default: 8000.0
    unit: "Hz"
  - id: high_gain
    paramId: 9
    name: "High"
    min: -12.0
    max: 12.0
    default: 0.0
    unit: "dB"

graph:
  nodes:
    - id: in
      type: audio_in
    - id: eq1
      type: biquad_filter
      params:
        freq: { param: low_freq }
        gain: { param: low_gain }
        mode: { value: 0.833 }   # lowShelf (mode index 5 out of 6)
    - id: eq2
      type: biquad_filter
      params:
        freq: { param: lmid_freq }
        q:    { param: lmid_q }
        gain: { param: lmid_gain }
        mode: { value: 0.667 }   # peaking (mode index 4 out of 6)
    - id: eq3
      type: biquad_filter
      params:
        freq: { param: hmid_freq }
        q:    { param: hmid_q }
        gain: { param: hmid_gain }
        mode: { value: 0.667 }   # peaking
    - id: eq4
      type: biquad_filter
      params:
        freq: { param: high_freq }
        gain: { param: high_gain }
        mode: { value: 1.0 }     # highShelf (mode index 6 out of 6)
    - id: out
      type: audio_out

  connections:
    - from: in.out
      to: eq1.in
    - from: eq1.out
      to: eq2.in
    - from: eq2.out
      to: eq3.in
    - from: eq3.out
      to: eq4.in
    - from: eq4.out
      to: out.in

ui:
  groups:
    - label: "Low"
      controls:
        - type: knob
          param: low_freq
          size: small
        - type: slider
          param: low_gain
    - label: "Low Mid"
      controls:
        - type: knob
          param: lmid_freq
          size: small
        - type: knob
          param: lmid_q
          size: small
        - type: slider
          param: lmid_gain
    - label: "High Mid"
      controls:
        - type: knob
          param: hmid_freq
          size: small
        - type: knob
          param: hmid_q
          size: small
        - type: slider
          param: hmid_gain
    - label: "High"
      controls:
        - type: knob
          param: high_freq
          size: small
        - type: slider
          param: high_gain
    - label: "Output"
      controls:
        - type: vumeter
          source: out
        - type: button
          action: reset
          label: "Flat"