Phonalyser.web

Precision audio measurement workbench: signal generator, oscilloscope, FFT analyser.

Press F1 anywhere in the application to open this help. Press Ctrl+F1 to jump directly to the section covering the control that currently has focus.

🌐 This build runs on Chromium browsers only - Google Chrome, Microsoft Edge, Opera or Brave. On any other browser it does not start. What else differs in a browser - no bit depth, the rate set in Windows, WebUSB for the QA40x, the page a bench serves - is collected in Phonalyser in a browser.

🚀 World's shortest HOW-TO - the entire parts-per-billion THD measurement, calibration to result, on one screen. Start here.

🔍 Index & search - search the whole manual, or browse the A-Z list of topics and terms.

💡 Tips - small things that make a big difference, also shown one at a time at startup.

🙏 Credits & acknowledgements - inspiration and thanks.

📜 What's new - the full release history.

Modules

Generator - tone generation, sweep, noise, WAV-file playback Oscilloscope - live time-domain view, trigger, measurement table FFT analyser - spectrum, harmonics, THD / SNR / ENOB Frequency response - swept magnitude & phase, RIAA / IEC reference, compare mode Tune-notch wizard - trim a twin-T notch filter live onto a target frequency DAC pre-distortion wizard - cancel the DAC's own harmonics for a sub-ppb stimulus Preferences - audio backend & devices, scope and FFT appearance Phonalyser in a browser - Chromium only, the Web Audio and QA40x backends, and the page a bench serves Windows input device - set the capture (and playback) sample rate the browser can't choose Audio backends - which engine drives the converters on each OS, the hardware-volume discipline on Linux/macOS, the macOS aggregate-device workaround The Phonalyser server - run the machine your hardware is wired to as a network bench, and measure through it from anywhere on the LAN Editing the settings as JSON - open the settings and the card profiles as text, with completion and per-key help

Theory of operation

Theory of operation - how the instrument works inside: audio backend, ring buffer & consumers, DDS signal generator

Tools & bench

Measurement bench & wiring - Faraday cage, CAT.8 twisted pair with XLR, single-point grounding, and the induced-noise budget

Layout

Main window - multifunctional tab

The main window is split into a Generator pane on the left (its width is adjustable - drag the sash, or set it in Preferences) and a vertical sash between Oscilloscope (top) and FFT analyser (bottom) on the right. Each pane can be collapsed to its title strip by double-clicking the title bar; double-clicking again restores it.

Each module has its own toolbar - a settings-tab strip below the main view with tabs for the per-module settings. The tab strip can be collapsed in turn (double-click the strip) to reclaim vertical space for the visible chart.

Conventions

Step selectors - fields like V/div, t/div, FFT length have small up/down arrows. The mouse wheel scrolls through standard values (1-2-5-10) and a manual typed value is accepted when it makes sense for the field.
Numeric fields - accept typed values plus mouse-wheel stepping. The wheel step is per-field (5 % for frequency, ±1 unit for harmonic numbers, etc.).
Tab tiles - the small badges painted under each tab label show the active value for that tab's most important controls at a glance, even when the tab body is collapsed.
Crosshair - hovering inside a chart shows a dashed cross with a floating readout box near the cursor.

Help -> About Phonalyser.web shows the version and links to the project repository. Use Help -> Report a problem to file an issue on GitHub.