Bass Test & Subwoofer Test

A bass test and subwoofer test that runs in your browser: step a tone down from 200 Hz to 16 Hz to hear how low your speakers, subwoofer or headphones go, find the note where the bass fades out, set a subwoofer's phase against your main speakers by ear, and sweep the bass for rattles, booms and dips. Each test says what you should hear and what to do when it sounds wrong.

Before you start: leave the level at −24 and start with your volume low. Bass tones sound quieter than they are, and a speaker pushed too hard clacks or buzzes: stop the moment it does. Every test stops by itself; Esc stops it sooner.

−24 dBFS

How loud this page plays, below digital full scale. Set your volume with it at −24 first.

Bass test: how low do your speakers and subwoofer go?

Sine tones at one-third-octave steps from 200 Hz down to 16 Hz, 2.5 seconds each. Or tap any step to hold it for 15 seconds.

You should hear
A clean, low tone that gets deeper and quieter step by step until it fades. The last step you can still hear as a tone is roughly where your system's bass ends. Small bookshelf speakers often fade between 40 and 60 Hz, large floorstanders and most subwoofers reach the 20s and 30s, and laptop and phone speakers give out above 100 Hz. Closed headphones that seal well can play the lowest steps clearly.
If it sounds wrong
  • A step turns into a buzz, a rattle or a higher pitch: something is vibrating, or the speaker has run out of travel at that level. Turn it down.
  • One step booms and the next nearly vanishes: in a room that is most often a room mode, and moving your seat or the subwoofer changes it.
  • A subwoofer goes quiet below a step it should play: check its low-pass or crossover knob, and the speaker size setting on your receiver, which decides what bass reaches the subwoofer at all.

Find the lowest note your system plays

One tone gliding down from 120 Hz to 15 Hz over 40 seconds. Press Stop the moment it fades out: the readout keeps the frequency you stopped at.

You should hear
A low hum that sinks smoothly and gets quieter, then fades into a pressure or nothing at all. Where you press Stop is roughly the bass limit of your speakers or subwoofer in your room, at this level and from your seat. Ears need much more level to hear the deepest notes, so part of the fade can be your hearing as well as the gear.
If it sounds wrong
  • The tone jumps in loudness on the way down instead of fading smoothly: the room is adding and cancelling bass at those notes. Run it again a meter away and compare.
  • It fades far higher than the speaker's specification: check the speaker size and crossover settings on your receiver, and that a port or the subwoofer is not blocked.

Subwoofer phase test: 0 or 180 degrees?

A steady tone for 30 seconds at your crossover frequency, the note where the subwoofer hands over to your main speakers and both play. Pick the one set on your receiver or subwoofer, or 80 Hz if you are not sure.

What to do
Sit in your listening seat with the tone playing while someone flips the subwoofer's phase switch between 0 and 180, or turns its phase knob slowly. Keep the setting where the tone sounds loudest and fullest: there the subwoofer and the main speakers push together. Where it sounds thinnest, they cancel.
If it sounds wrong
  • Both settings sound the same: the subwoofer may not be playing this note at all. Check its crossover or low-pass knob and its level, then try the next frequency down.
  • The loudest setting changes when you move: judge it from the seat you listen from. Moving the subwoofer changes the answer too, so run the test again after any move.

Bass sweep: rattles, booms and dips

One tone gliding up from 20 Hz to 200 Hz over 30 seconds, the classic rattle test. Press Stop at anything odd to keep its frequency.

You should hear
A smooth rise in pitch that fades in from the bottom and stays at an even loudness, with nothing buzzing along with it.
If it sounds wrong
  • A rattle or a buzz at one frequency: something is loose, from a grille, a shelf or a window to the subwoofer's own panels. Hold a steady tone at that frequency and walk round the room to find it.
  • A boom or a deep dip that changes when you move your head: a room mode. The room mode calculator predicts where they fall from the room's size.
  • A dip around your crossover frequency: the subwoofer and the main speakers are cancelling there. Run the phase test above, or move the subwoofer.

What a bass test can and cannot tell you

Bass is where speakers, subwoofers and rooms differ most, and where a spec sheet says least about what you hear from your seat. A sine tone holds one note, so playing them one after another asks the whole chain a plain question: how loud does it play this note, here?

Below a couple of hundred hertz the room has as much say as the speaker. Sound bouncing between the walls builds up at some notes and cancels at others, so one step can boom while the next nearly disappears, and moving a meter changes which ones do it. That is why every test here asks you to listen from the seat you use.

A subwoofer adds a second source for the same notes. Around the crossover frequency both it and the main speakers play, and whether they add up or cancel depends on their timing at your seat, which the phase switch and the subwoofer's position decide.

The ideas behind the controls

Bass extension
The lowest note a speaker, subwoofer or headphone plays at a useful level. A spec sheet quotes it under ideal conditions; your room and seat move it.
Crossover
The frequency where a subwoofer hands over to the main speakers. Around it both play, so their timing decides whether they reinforce each other or cancel.
Subwoofer phase
Whether the subwoofer's cone moves in step with the main speakers at the crossover. A switch flips it by 180 degrees; a knob shifts it gradually.
Room mode
A note at which sound bouncing between two walls reinforces itself, loud at some seats and nearly silent at others. In a small room, modes shape most of the bass you hear.

Bass and subwoofer test FAQ

  1. How do I test my bass?

    Play the bass test tones from 200 Hz down to 16 Hz at a moderate level and listen for the last step that still sounds like a clean, low tone: that is roughly where your speakers, subwoofer or headphones stop. Then run the lowest-note sweep and press Stop when the tone fades out, and the readout keeps the frequency. Start quiet, since bass tones sound quieter than they are, and stop at any buzz or clack.

  2. How do I test my subwoofer?

    Run three checks from your listening seat. The bass tones and the lowest-note sweep show how low it plays, the phase test at your crossover frequency shows whether it adds to your main speakers or cancels them, and the bass sweep finds rattles and booms. If nothing below 80 Hz or so reaches the subwoofer, look at the receiver first: its speaker setup decides which bass goes to the subwoofer, usually by setting the main speakers to Small. When the receiver sets the crossover, turn the subwoofer's own low-pass knob to its highest setting or its LFE position, so the two filters do not stack.

  3. Can I use the bass test with headphones?

    Yes. Closed headphones and in-ear monitors that seal well can play down to 20 Hz, and the seal decides most of it: a gap at the pads or a loose ear tip loses the deepest steps first. Open-back headphones usually fade earlier. Keep the level moderate, because a headphone driver can rattle on the lowest steps when it is pushed.

  4. Why can't I hear the 16 Hz and 20 Hz tones?

    Usually because few speakers play them: most bookshelf speakers fade between 40 and 60 Hz, and only large subwoofers reach the lowest steps. Your ears play a part too. Hearing needs far more level at 20 Hz than in the midrange, so the deepest tones are felt as pressure as much as heard, and a 16 Hz tone at a safe level can seem like nothing at all. Most music sits higher: the open low E string of a bass guitar is 41 Hz.

  5. Should my subwoofer phase be set to 0 or 180?

    Whichever sounds louder at the crossover frequency from your seat. There is no right setting in general, because it depends on where the subwoofer sits relative to the main speakers and on the delay of the crossover itself. Play the phase test at your crossover frequency, flip the switch, and keep the setting where the tone sounds fullest. If the subwoofer has a variable phase knob, turn it slowly for the loudest point instead.

  6. Where should I put my subwoofer?

    Try the subwoofer crawl. Put the subwoofer at your listening seat, play the bass sweep or a steady tone around 40 to 60 Hz, then move around the floor where the subwoofer could go, with your head near the floor, and listen for the spot where the bass sounds fullest and most even. Put the subwoofer there. It works because the room treats the path from the subwoofer to you the same in both directions.