Subwoofer Test Tones
Play sustained low-frequency sine tones (20–100 Hz) and slow bass sweeps straight through your subwoofer or speakers. Use them to check that your sub actually reproduces a given note, to find its drop-off point by ear, and to compare placements. Each tone fades in slowly so there is no thump.
ℹ This is an uncalibrated listening aid, not a measurement. It plays a clean sine tone — it cannot tell you SPL in decibels, the sub’s true frequency response, or its distortion. Crucially, most laptops, phones, and earbuds cannot reproduce below ~50–80 Hz, so a silent low tone may be your device, not your sub. Your ears are also far less sensitive to deep bass (equal-loudness), so low tones need more level to sound as loud. For real numbers, use a calibrated SPL meter or a measurement mic with REW.
⚠ Safe-volume warning. Sustained high-level bass can damage subwoofers, drivers, and your hearing, and can shake objects loose. Start with the volume LOW and raise it slowly. Deep tones can be physically intense even when they sound quiet — if your sub makes mechanical, flapping, distorted, or rattling noises, turn it down immediately. Never run loud test tones for long periods.
Sustained test tones (Hz)
Low-frequency sweep
Placement comparison workflow
- Play a single sustained tone where the bass is currently weak or uneven — 40 or 50 Hz is a good start.
- Walk to your usual listening seat and judge how loud and even the bass feels there.
- Stop, move the sub to a new spot (corners, along a wall, the “subwoofer crawl”), then play the same tone again.
- Keep the master volume fixed between trials so you are comparing positions, not levels.
- Choose the placement where the tone is loudest and most even across seats. This is a by-ear comparison — for real numbers, measure with an SPL meter or a measurement mic and REW.
How It Works
This tool uses your browser’s Web Audio API to synthesise a pure sine tone at a chosen low frequency and route it — through a gain stage that controls the volume — to your audio output. That output is whatever your computer or phone is connected to: built-in speakers, headphones, a soundbar, or a hi-fi/home-theatre system feeding a subwoofer. The tone is the intended sound; nothing is recorded, measured, or uploaded. Each tone fades in slowly (about half a second) to avoid the loud thump a sudden bass transient can put through a cone, and fades out briefly when you stop to avoid a click.
The discrete buttons play sustained tones at 20, 25, 30, 40, 50, 60, 80 and 100 Hz — the region a subwoofer is meant to cover. The two sweeps glide smoothly between 100 Hz and 20 Hz (and back) over about twelve seconds, on a logarithmic path so each octave gets equal time. Sweeping down is the easiest way to find where your system drops off: listen for the point where the bass fades, thins out, or vanishes, then switch to the nearest fixed tone to confirm it by ear.
Two honest limits matter. First, this is uncalibrated: what you hear is your whole playback chain — amplifier, sub, crossover, room, and your ears — not the sub in isolation, and there is no decibel reading. Second, the human ear is dramatically less sensitive at low frequencies (the equal-loudness effect described by the ISO 226 curves), so a 30 Hz tone needs far more level than a 100 Hz tone to seem equally loud. And if a low tone is silent, suspect your device before your sub — most laptops, phones, and earbuds simply cannot move enough air below 50–80 Hz. Treat the result as a guide, and reach for an SPL meter or a measurement microphone with REW when you need a real measurement.