Web Audio low frequency demo

18 Hz Infrasound Tone Lab

A browser-only sine tone generator inspired by research on low-frequency sound and mood. It can play 18 Hz, sweep nearby frequencies, run a 40 Hz speaker check, and layer the tone over a local music file without uploading anything.

Read this before playing sound

This is not a calibrated reproduction of a lab experiment. A browser can set digital amplitude in dBFS, but it cannot know real sound pressure level from your phone, laptop, headphones, or speakers. Most phones and laptops will not reproduce 18 Hz cleanly. Start very low, avoid loud headphones, and stop immediately if you notice discomfort, rattling, distortion, pressure, or speaker stress.

I understand this is an uncalibrated demo and I will start with low system volume.

Tone controls

Frequency 18.0 Hz Digital level -36 dBFS Auto stop 30 seconds

Elapsed: 0:00.0 Remaining: 0:30.0

Optional local music bed

Add a local audio file if you want to hear the low tone under music. The file stays in your browser and is not uploaded.

Audio file Music volume 45%

Start and stop music with tone Loop music

What this can and cannot do

Treat this as a practical sound test and educational demo, not as a medical, diagnostic, or laboratory-grade acoustic instrument.

18 Hz is hard to reproduce Small speakers often roll off below 40 to 80 Hz. You may hear distortion or harmonics instead of the fundamental.

dBFS is not dB SPL The slider controls digital signal level only. Real acoustic loudness depends on hardware, room, distance, and volume.

Use the 40 Hz check first 40 Hz is more likely to be audible on consumer speakers. If that distorts, do not push the lower test louder.