Measure, don't guess
Every sound decision in FaustWave can be a number before it is an opinion. The Analysis tools record what reaches the master, or read a sample from the store, and return one report: loudness, crest, energy per band, where the root sits, mono-compatibility, onsets with a click score, single-sample steps, and a tonality verdict. Optionally the numbers are placed against a reference window — what professional material measures — and each window comes back as inside / below / above.
This book exists because of one project. Around the World (the bundled trap demo) was built in a day where every "the bass is too thick", "something clicks", "these hats sound like an alarm clock" was answered by a measurement first. Three findings the ear had misread and the numbers caught:
- a click on every second 808 note that was a runtime bug, not the patch (half a block of exact zeros at each note start);
- a "feel" problem that was the ducker taking -8 dB exactly where the 808 notes landed;
- a sample pack whose 36 "hats" were all a 7 kHz line (one FFT bin carried 10 % of the energy; a real 909 hat measures 2–3 %).
Where it lives
The Analysis pane sits in two shipped views. In Build it is under the Inspector — the knob you turn and the number it changes in one column. In Signal it is the audio half of "is something wrong" beside the MIDI half (Devices, MIDI Monitor, Routing). It is not in Perform: a set is played, not measured.
actions:
- action_id: view.open
input: { view: build }
label: "▶ Open the Build view (Analysis under the Inspector)"
- action_id: surface.open
input: { surface: analysis }
label: "▶ Or put the Analysis pane on the current view"The pane has three controls: a take picker (every recording, newest first), Measure (analyse the picked take), and Capture (record the next bars and analyse them). The vs trap-808 chip toggles the reference window.
The four actions
| Action | What it measures | When |
|---|---|---|
analysis.capture { bars, seconds, reference } | Records the master for bars (default 8, at the live BPM; ceiling 60 s), stops, returns the report and the new recording id. Start the transport first — a silent take returns an error. | The loop while you tweak: change a knob, capture four bars, compare. |
analysis.recording { recording_id, reference } | A finished take from the Recorder library (recordings.list), the whole file, offline. Leading and trailing silence trimmed; the first 120 s measured. | A take you already have. |
analysis.sample { sha256, reference } | A sample from the store (samples.list). PCM WAV only. | Before wiring a sample into a kit — the tonality verdict is the alarm-clock detector. |
analysis.references | The reference profiles: id, provenance, every window with its question, lo/hi and unit. | Read once, so "inside" means something when you quote it. |
All four return the same report shape; the next chapter reads it line by line.
actions:
- action_id: analysis.references
input: {}
label: "▶ What does the trap-808 window contain?"
- action_id: transport.play
input: {}
label: "▶ 1. Play"
- action_id: analysis.capture
input: { bars: 4, reference: trap-808 }
label: "▶ 2. Capture four bars and judge them against the pro window"