Docstrings: Google sections and cross-references; licence headers on every file

docs/conf.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Sphinx configuration for the audioeffects documentation.
 
 Everything shared by the PyDevices documentation projects (theme, top bar,

lib/audioeffects/__init__.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Forty-five effect classes built out of audiodsp's audio nodes.
 
 Every class wires itself from an audio source - a synthesizer, an

lib/audioeffects/_component.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The construction shape every rebuilt effect class is built on.
 
 It replaced `_core.py`, the pre-contract shape, in which a module-level

lib/audioeffects/_iso.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """ISO centre frequencies, kept as a shared private constant.
 
 The old family GraphicEQ walked these ten centres. The rebuilt GraphicEQ

lib/audioeffects/airspace.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`AirSpace` - a tape echo sent into a chamber, with the dry beside it.
 
 You send your signal to a tape echo whose repeats feed an echo chamber, and

lib/audioeffects/analogdelay.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`AnalogDelay` - a bucket-brigade delay whose Time knob is its clock.
 
 The player's text is the class docstring, and every sentence in it that

lib/audioeffects/autopan.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`AutoPan` - an auto-panner: a pan law under an LFO.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's

lib/audioeffects/bandpass.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`BandPass` - the two-pole resonant band-pass, rebuilt on `audiobiquad`.
 
 The player's text is the class docstring; the `CLAIMS` table in the

lib/audioeffects/bitcrusher.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Bitcrusher` — a linear hold, the SP-1200's two numbers as knobs.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's

lib/audioeffects/cabinetsim.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`CabinetSim` - a designed guitar-cabinet response, two characters.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's

lib/audioeffects/chorus.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Chorus` - one delayed voice on a clock-modulated bucket-brigade line.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's

lib/audioeffects/combfilter.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`CombFilter` - a delay line short enough to be a pitch, fed back on
 itself.
 

lib/audioeffects/compressor.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Compressor` - compressor characters on a shared palette.
 
 The player's text is the class docstring; the `CLAIMS` table in the

lib/audioeffects/convolutionreverb.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`ConvolutionReverb` - a room made by convolution, synthesized or loaded.
 
 The player's text is the class docstring, and every sentence in it that

lib/audioeffects/deesser.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The dbx 902 de-esser: sibilance measured against the programme, not
 against a threshold knob.
 

lib/audioeffects/digitaldelay.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`DigitalDelay` - a clean digital delay with the Boss DD-2's control law.
 
 Your dry signal passes untouched, and one clean repeat follows it, fed back

lib/audioeffects/distortion.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Distortion` - the ProCo Rat, with a Boss pedal as a second character.
 
 The player's text is the class docstring; the `CLAIMS` table in the

lib/audioeffects/dynamiceq.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`DynamicEQ` - one equaliser band that only moves when there is
 something in it.
 

lib/audioeffects/exciter.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Exciter` - dry plus a high-passed harmonic branch.
 
 The player's text is the class docstring; the `CLAIMS` table in the

lib/audioeffects/expander.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Expander` - a downward expander in the Drawmer DS201's shape.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's

lib/audioeffects/flanger.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Flanger` - a swept comb on CircuitPython's own `audiodelays.Flanger`.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's

lib/audioeffects/fuzz.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Fuzz` - a biased germanium pair, with a Big Muff cascade as a second character.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's

lib/audioeffects/graphiceq.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`GraphicEQ` - ten octave bands and two level sliders, after the MXR
 M-108 Ten Band.
 

lib/audioeffects/harmonizer.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Harmonizer` - a harmony of pitch-shifted voices.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's

lib/audioeffects/highpass.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`HighPass` - the low-cut: a two-pole analog high-pass whose transmission
 zero at DC is exact, not nearly.
 

lib/audioeffects/ladderfilter.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`LadderFilter` - the Moog transistor ladder, rebuilt on `audioladder`.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's

lib/audioeffects/limiter.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """A lookahead brickwall limiter: a ceiling the signal does not get past.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's

lib/audioeffects/lowpass.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`LowPass` - the two-pole analog prototype every synth and console
 low-pass is a version of, digitised without losing its tail.
 

lib/audioeffects/multibandcompressor.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`MultibandCompressor` - split-band compression, two or three bands.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's

lib/audioeffects/multitapdelay.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`MultiTapDelay` - one recording read by several heads on a fixed grid.
 
 The player's text is the class docstring, and every sentence in it that

lib/audioeffects/noisegate.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`NoiseGate` - a noise gate after the Drawmer DS201.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's

lib/audioeffects/notch.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Notch` - the two-pole band-stop: everything except one band, tuned.
 
 The player's text is the class docstring; the `CLAIMS` table in the

lib/audioeffects/octaver.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Octaver` - the analog octave-down.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's

lib/audioeffects/overdrive.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Overdrive` - a Tube Screamer-shaped boost: dry plus a clipped shelf.
 
 The player's text is the class docstring; the `CLAIMS` table in the

lib/audioeffects/parametriceq.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`ParametricEQ` - the Pultec EQP-1A's two low networks and its resonant
 top, with three API 550A proportional-Q bells in the middle.
 

lib/audioeffects/phaser.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Phaser` - four first-order all-pass stages swept the way a Phase 90 is.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's

lib/audioeffects/pingpongdelay.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`PingPongDelay` - repeats that alternate between the speakers.
 
 The player's text is the class docstring, and every sentence in it that

lib/audioeffects/pitchshifter.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`PitchShifter` - a fixed-interval splice pitch shifter.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's

lib/audioeffects/rack.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Rack` - a serial chain of effects, as a single effect.
 
 The player's text is the class docstring, and the sentences in it that make

lib/audioeffects/reverb.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Reverb` - Dattorro's plate network, cut four ways: a plate, a room, a
 chamber and a hall.
 

lib/audioeffects/ringmod.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`RingMod` - Bode multiplier-type ring, with a switching character.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's

lib/audioeffects/saturation.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Saturation` - a tube stage, a tape chain, or transformer iron.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's

lib/audioeffects/shimmerhall.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`ShimmerHall` - a hall that rings an octave above what you play.
 
 You play into a hall, and a pitch shifter beside it makes the tail ring at

lib/audioeffects/slapbackdelay.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`SlapbackDelay` - one tape repeat after the dry, in mono: the Sun Studio slap.
 
 The player's text is the class docstring, and every sentence in it that

lib/audioeffects/stereowidener.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`StereoWidener` - a stereo widener with Haas and Mid/Side characters.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's

lib/audioeffects/tapedelay.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`TapeDelay` - a tape echo with two transports: the Roland RE-201's motor
 and the Maestro EP-3's sliding head.
 

lib/audioeffects/transientshaper.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`TransientShaper` - transient shaping in the SPL Transient Designer's shape.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's

lib/audioeffects/tremolo.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Tremolo` — Fender bias-vary and optical characters on one Multiply.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's

lib/audioeffects/vibrato.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Vibrato` - a clock-modulated bucket-brigade line, wet alone.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's

manifest.py

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Freeze audioeffects into a MicroPython firmware.
 
 A firmware build that names audioeffects takes this file.