639 Hz Tone
Continuous 639 Hz reference tone — play instantly in your browser.
Fixed frequency: 639 Hz (Solfeggio reference)
Download a 639 Hz reference WAV (2 seconds, 44.1 kHz).
What this tool does
A 639 Hz tone vibrates 639 times per second. A mid-range Solfeggio reference for sustained listening sessions. This page locks the frequency so you can listen, compare equipment, or export a WAV without adjusting sliders.
How to use it
Tap Play to unlock audio (required on mobile browsers). Start at low volume, especially with headphones. Switch waveform to hear how harmonics change timbre while the fundamental stays at 639 Hz. Use Download WAV for an offline reference file.
Practical applications
Listeners use 639 Hz as a sustained reference within Solfeggio frequency lists. Musicians may compare it against standard 440 Hz tuning. No medical claims are made — treat this as an audio utility.
Frequently asked questions
Will 639 Hz damage my hearing?
Any sustained loud sound can cause harm. Keep volume moderate and take breaks.
Is audio processed on a server?
No. All synthesis runs locally in your browser.
Last updated: September 2025. Technical values (Hz) are locale-invariant.