Online Sound Test
Clean UI for frequency sweeps, but browser audio APIs limit precision for pros.

Free browser meter with FFT analysis, but calibration depends entirely on your microphone hardware.
People needing quick noise measurements without installing apps
Decibel X · NIOSH Sound Level Meter · Sound Meter Pro
Clean UI for frequency sweeps, but browser audio APIs limit precision for pros.
REW and Room EQ Wizard already do frequency sweeps with more features and calibration.
Spectral reassignment spectrogram plus multi-band correlation metering—pro tools quality, free and Linux-native.
Full C audio engine running in-browser via Emscripten with a custom ASCII notation language.
Plain JS tone generator with Solfeggio presets when dedicated apps exist.
Article-to-audio when ElevenLabs, Speechify, and Play.ht already dominate.