SoundCheck

A signal generator utility for macOS, to help sound engineers, audio technicians and audiophiles test sound recording and reproduction equipment. Generates test signals only — SoundCheck is not an audio analyser and never captures or measures audio.

Status

V1 is built: sine wave, pink noise, and white noise generators, with the full UI chrome (on/off, frequency field, level field, output device picker, per-channel mute/phase, live sample rate/bit depth display) wired end-to-end to a real AVAudioEngine graph, live Core Audio device enumeration, and persisted settings. See docs/v1-spec.md for the complete spec and the SoundCheck V1 map (closed) for how it was built.

V2 is in progress on the V2 map. Done so far: band-limited pink noise (5 presets + manual range) and 1/3-octave pink noise (31 ISO 266 bands), both live as sub-modes of the Pink signal type. Sine sweep and square wave are still being built out — see the map for current status.

Requirements

• macOS 14 (Sonoma) or later
• Any Mac — Apple Silicon or Intel. Releases ship as a universal binary.
• An audio output device (built-in speakers, headphones, USB interface, etc.). SoundCheck plays test signals only — it never records, so no microphone access is needed.

Install

1. Download the latest SoundCheck-vX.Y.Z.zip from the Releases page.
2. Double-click the .zip to unpack SoundCheck.app, then drag it into your Applications folder.
3. First launch. The app is signed for development but not notarized by Apple, so macOS Gatekeeper blocks it the first time. To open it anyway:
   • Right-click (or Control-click) SoundCheck.app → Open, then click Open in the dialog. macOS remembers your choice, so later launches are ordinary double-clicks.
   • If no Open button appears, clear the quarantine flag in Terminal and try again:

     xattr -dr com.apple.quarantine /Applications/SoundCheck.app
     

Heads up: because these builds use an Apple Development certificate and aren't notarized, some Macs may refuse to open the app at all rather than just warn. If the steps above don't work, build from source instead — a notarized, friction-free build is future work.

Running

1. Launch SoundCheck and pick your Output Device.
2. Choose a signal type (sine, pink, or white), set the frequency (sine) and level, and flip the generator On.
3. Use the per-channel mute / phase controls to send the signal where you need it.

Building and testing

xcodebuild -project SoundCheck.xcodeproj -scheme SoundCheck -destination 'platform=macOS' build
xcodebuild -project SoundCheck.xcodeproj -scheme SoundCheck -destination 'platform=macOS' test

Or open SoundCheck.xcodeproj in Xcode and use Cmd-R / Cmd-U. Requires Xcode (SwiftUI + AVAudioEngine + Core Audio); iOS portability is considered but not designed for yet.

Documentation

• docs/v1-spec.md — the V1 feature spec: signal types, screen layout, control behaviors, audio engine architecture, and the full decisions log.
• CONTEXT.md — domain glossary.
• docs/adr/ — architecture decision records.
• docs/research/ — research writeups backing specific technical decisions.

Roadmap

• V1: sine, pink noise, white noise. Done.
• V2: band-limited pink noise (done), 1/3-octave pink noise (31 standard ISO 266 bands, done), sine sweeps (in progress), square wave (not started).

Out of scope: any audio analysis, metering, or capture.

License

GPLv3 — see LICENSE.