Bass Test
How low do your speakers, subwoofer, or headphones stay audible? This is a listening check, not a measured cutoff. Play sine tones from 10 to 200 Hz and listen for where the tone disappears. Judge kick drums, mark room rattles, and compare phase. Free, in your browser.
Protect your speakers and ears. Start with your system volume low and raise it slowly. Low tones need far more cone movement than music, and below 30 Hz you hear very little while the driver works hard. Stop at once if you hear slapping, crackling or a buzz from the speaker itself. Laptop and phone speakers cannot play these notes, so turning them up only strains them.
1. Bass tone player
A pure sine at this slider's frequency, in 0.1 Hz steps. The large number matches it while the tone plays. Step down through the presets and note where the tone gets weak. If a 25 Hz tone sounds like a 50 Hz hum, you are hearing distortion, not the sine.
2. Sub-bass sweep: where the tone disappears
Tap the moment the tone fades out. The number on screen is the sine oscillator, and the mark stores that same frequency. Your ears are much less sensitive below 40 Hz, so the mark is where the tone disappeared or appeared for you, not a measured cutoff. Run it both ways and take the average.
3. Kick drum test
Short sines at the hertz on each button, four hits per tuning, plus a brief noise click. Real kicks sit around 50 to 60 Hz. Listen for the point where the thump turns into just that click: the sine is too low to hear. Sealed headphones and subwoofers often keep a solid body down to 30 Hz.
4. Rattle and buzz finder
None yet.
A slow sweep at a steady level. Walk around the room while it plays and press Mark when something buzzes: picture frames, window panes, shelves, the speaker's own grille. Press Hold to freeze the tone, nudge it by 1 Hz to find the worst spot, then press a hand on each suspect until the buzz stops.
5. Subwoofer crossover and phase helper
80 Hz is the usual crossover point between a subwoofer and the main speakers. In the alternating mode, the in-phase slot should sound clearly fuller and more centred. In the inverted slot the left and right speakers fight each other, so the bass goes thin and vague. If it is the other way round, one speaker is wired with + and − swapped.
With a subwoofer that gets its bass from the left and right channels, the inverted slot often makes the sub go nearly silent, because the two cancel when summed. To set the sub's phase switch or dial, play the steady tone, sit in your usual seat and pick the setting (0 or 180 degrees, or anywhere on the dial) where 80 Hz sounds loudest.
How to read your bass test
What the numbers mean
Sub-bass runs from 20 to about 60 Hz: the rumble in film explosions, pipe organs and 808 kicks, felt as much as heard. Bass runs from 60 to 250 Hz, where kick drums, bass guitar and the weight of male voices live. Below 20 Hz is infrasound, which most systems cannot play and most people cannot hear. A system that reaches 40 Hz plays nearly all music; 25 Hz and below is home cinema territory.
Headphones vs. speakers: the seal matters
Closed headphones and in-ear monitors only need to pressurise the small space in your ear canal, so a good pair can play 20 Hz cleanly. That works only with a seal. A loose ear tip, glasses arms or hair under the pads can cost you everything below 100 Hz. If the tone disappears early, try a bigger tip and run the sweep again. Speakers have to move a whole room of air, which is why the lowest notes need big drivers or a subwoofer.
Bass boost on the box
Small drivers roll off around 80 to 150 Hz. Portable speakers and soundbars marketed with "extra bass" usually boost the 100 to 150 Hz region to make up for it. That sounds punchy, but a boost is not the same as playing 30 Hz. Compare the sweep mark with the range printed on the box. A claim of 20 Hz from a palm-sized speaker often fades out around 80 Hz here.
Room, placement and safety
Room modes and the subwoofer crawl
Bass waves are metres long and bounce between walls, creating peaks and nulls that can differ by 15 dB from one seat to the next. If a note in the tone player booms while its neighbour vanishes, that is the room, not the speaker. Corner placement gives the most output but also excites the most modes. For the subwoofer crawl, put the sub in your listening seat, play the tone or a bass-heavy track, crawl around the room's edges and place the sub where the bass sounds most even.
Play it safe
Low frequencies can damage a driver before they sound loud, because you hear them poorly while the cone moves a long way. Keep the volume moderate, and never boost a tone that sounds distorted. Long sessions of loud low tones also tire your ears, so take breaks.
Related tools
Check the full 20 Hz to 20 kHz range with the frequency response test, check speaker channels with the surround sound test, play any frequency or waveform with the tone generator, and check left, right and polarity with the headphone test.
Frequently asked questions
What am I listening for?
Where the low tone disappears. The tone player is a sine from 10 to 200 Hz: step down and note where it gets weak, or where a low note sounds like a higher hum. That hum is distortion, not the sine. On the sweep, press the big button or Space when the tone fades out on the way down, or when it first appears on the way up. Kick hits, rattle marks, and the phase helper are listening checks too.
Does this measure my subwoofer cutoff?
No. This is a listening check, not a lab measurement. The page only plays tones. It never opens the microphone and it does not compute a cutoff. The hertz you mark is the oscillator frequency at the moment you tap, which is where the tone disappeared or appeared for you. The room, the seat, and your hearing all change that.
Should I use headphones or a subwoofer?
Either, and they will not agree. Closed headphones and in-ear monitors only pressurise the ear canal, so a tight seal can keep a 20 Hz sine audible. A loose tip, glasses arms, or hair under the pads can wipe out notes under about 100 Hz. A subwoofer has to move the air in the room, so the same sine may fade sooner, boom in one seat, or rattle a frame. Sit in your usual seat, then try another seat before you blame the sub.
How do I stop the sound?
Press Stop all, or press the active control again (Stop tone, Cancel, or Stop). Leaving the page stops every oscillator, sets the output gain to zero, and closes the audio context. Nothing plays until you click a play control.
What is the large hertz number?
The sine oscillator frequency, not a measured result. A steady tone is the slider frequency, in 0.1 Hz steps from 10 to 200. A sub-bass sweep is a log glide between 200 Hz and 10 Hz over 20 seconds. The rattle sweep glides from 30 Hz to 120 Hz over 60 seconds, and Hold freezes that oscillator on the frequency shown. The phase helper is an 80 Hz sine. Each kick is a short sine at the hertz printed on its button, plus a brief noise click.
Why is playback quiet, and is volume 0 silent?
Playback starts only after a play click. The slider begins at 20%, and a saved level comes back no higher than 40%. Output gain is the square of volume over 100, then each tone is scaled below full level. At 0% that gain is exactly zero, so the tone is silent. Low notes move a speaker cone a long way before they sound loud, so start with the system volume low and press Stop all if the driver slaps or buzzes.