Infrasound Generator
Generate pure 1–20 Hz sub-bass and infrasonic sine tones for subwoofer testing, tactile-bass experiments, and acoustic-research demos. The volume ramps up slowly to protect your cone, and a slow-oscillation display lets you see the signal even when you can’t hear it.
ℹ Can your device even do this? Almost certainly not. A true sub-20 Hz acoustic output is essentially impossible on consumer gear — laptops, phones, earbuds and most speakers simply cannot move enough air this low. You will usually hear nothing, or only audible harmonic distortion or port chuffing — that buzz is not the real tone, it is your speaker straining. Only a capable subwoofer produces genuine output below ~20 Hz, and even then it is felt through the body, not heard as a pitch. This is a tone generator, not a measurement: there is no microphone, and nothing is recorded or uploaded.
⚠ Safety & equipment warning. Below ~20 Hz a driver’s cone must move dramatically further to make sound — excursion roughly quadruples for every octave you go down — so a loud sub-bass tone can over-excurt and physically damage a subwoofer (torn surrounds, broken glue joints, bottomed-out voice coils). Keep the volume LOW; this is why real systems use a subsonic filter near 20 Hz. High-level infrasound exposure can also cause pressure, nausea, fatigue, or disorientation. Stop immediately if your speaker makes flapping, mechanical, or distressed sounds, or if you feel unwell.
Preset frequencies (Hz)
Audio output is digitally clean down to 1 Hz — but your speaker is the real limit, not the math.
Tactile-bass perception guide
- Below ~20 Hz you stop hearing a pitch. The tonal sensation ceases around 20 Hz; from there down, infrasound is sensed (if at all) as pressure and vibration in the chest and body rather than as a note.
- It takes a lot of level to feel anything. Body vibration only becomes perceptible roughly 20–40 dB above the hearing threshold, and that threshold is already very high in the infrasonic range — so weak playback feels like nothing at all.
- Below ~10 Hz you may perceive single cycles rather than a continuous tone — a slow, pulsing pressure — but again only at very high SPL on a capable subwoofer.
- Touch the cone or sit near the sub. Resting a hand lightly near (not on) a working subwoofer is often the only way to confirm a true infrasonic tone is being produced when your ears report silence.
How It Works
This tool uses your browser’s Web Audio API to synthesise a pure sine tone between 1 and 20 Hz and route it — through a gentle subsonic high-pass guard and a gain stage that controls the volume — to your audio output. That output is whatever your computer or phone drives: built-in speakers, headphones, a soundbar, or a hi-fi/home-theatre system feeding a subwoofer. The tone is the intended sound; there is no microphone and nothing is recorded, measured, or uploaded. The level ramps up slowly (about a second) rather than starting abruptly, because a sudden low-frequency transient acts almost like a DC step and can slam a subwoofer cone past its limits. The slow-oscillation waveform display animates at the real frequency, so you can watch the wave crawl across the screen even when your speakers produce no audible sound at all.
Here is the honest physics. Below about 20 Hz, a driver has to move its cone dramatically further to radiate the same sound — excursion roughly quadruples for every octave down. Tiny laptop, phone, and earbud transducers cannot come close to that displacement, so they produce essentially no acoustic energy in this band; if you hear a buzz, you are almost always hearing audible harmonic distortion or port noise, not the fundamental. Even a good full-range speaker typically rolls off below ~30–40 Hz, and most subwoofers are designed to stop around 20 Hz with a deliberate subsonic filter so they don’t destroy themselves trying to reproduce the impossible. Only a specialised, capable subwoofer makes real output below 20 Hz.
And even when the sound is produced, you mostly won’t hear it. The human hearing threshold rises steeply as frequency falls — from roughly 65 dB SPL at 32 Hz to around 90 dB at 16 Hz and ~100 dB by 10 Hz (Møller & Pedersen, Hearing at Low and Infrasonic Frequencies, 2004) — and the tonal sensation of “a note” fades out around 20 Hz. Below that, infrasound is felt, not heard: a sense of pressure or vibration in the chest and body that only appears at very high levels (about 20–40 dB above threshold). Below ~10 Hz you may even perceive individual cycles instead of a continuous tone. So treat this as an educational and experimental generator, not a calibrated source — what reaches your ears depends entirely on your hardware, and silence here is normal, not a fault.