Bass sweep
Start at a low volume. Deep tones sound quiet, but they move a lot of air. Turn up slowly. If you hear knocking, flapping or hard buzzing from the speaker, turn down at once.
About the subwoofer test
This page plays bass test tones for your subwoofer. A slow bass sweep glides from 20 Hz to 200 Hz in 30 seconds. Bass tone buttons play one fixed tone each: 20, 30, 40, 50, 60, 80, 100 and 120 Hz. Use them to find where your subwoofer fades out, to check the crossover, and to find things that rattle in the room.
The tones are pure sine waves, made live in your browser. Nothing is downloaded, so you can play a tone for as long as you need, and change it while it plays.
You need a real subwoofer or big speakers for this test. A phone or laptop speaker cannot play deep bass — often nothing below 100–200 Hz.
Features
- Bass sweep — a slow glide from 20 to 200 Hz in 30 seconds; type your own range and length
- Fixed bass tones — 20, 30, 40, 50, 60, 80, 100 and 120 Hz, one tap each
- Fine control — a slider from 15 to 240 Hz, and steps of 1 Hz and 10 Hz
- Bass zone hint — the line under the number says if a tone is deep bass, low bass, the crossover zone or upper bass
- Clean test signal — a pure sine tone; square, triangle and sawtooth are there too
- Remembers your settings — your tone, wave shape and volume stay in this browser
- Free and private — no app, no sign-up, nothing is recorded or sent anywhere
Find where your subwoofer fades out
- Set this page's Volume low and your amplifier to a normal level. Press 50 Hz. You should hear (and feel) a clear, steady hum.
- Press 40 Hz, then 30 Hz, then 20 Hz. Listen to how loud each one is.
- Where the hum becomes much weaker, your subwoofer is near its limit. That is roughly its lowest useful tone.
- For a finer answer, start the Bass sweep. Press Stop the sweep when the bass comes in clearly. The number shows where the sweep stopped. Then use the −1 Hz / +1 Hz steps.
Many home subwoofers reach about 25–40 Hz. Small subwoofers that come with a soundbar often stop around 40–50 Hz.
Do not be fooled by your ears. People hear deep bass much less well than middle tones. At 20–30 Hz a tone must be much stronger to sound as loud as 100 Hz. So a quieter 25 Hz is normal. It does not mean that the subwoofer is broken.
Find rattles and buzzes
Deep tones make loose things shake: windows, shelves, picture frames, a lamp, even the panels of the subwoofer itself.
- Start the Bass sweep at a medium volume. Type 60 in Length (seconds) for a slower sweep.
- Walk around the room while it plays. When something rattles, press Stop the sweep. The number shows the tone that made it shake.
- Press Play to hold that tone, and find the thing that rattles. Move it, press it, or put a small piece of felt under it.
Check the crossover
The crossover is the tone where the subwoofer hands over to the main speakers. 80 Hz is a common starting point on home theater receivers. The hint under the number uses these zones:
| Tones | Zone | What plays them |
|---|---|---|
| below 40 Hz | deep bass | only big subwoofers; you feel it as much as you hear it |
| 40 to 79 Hz | low bass | the subwoofer's main job |
| 80 to 120 Hz | crossover zone | the subwoofer and the main speakers share it |
| above 120 Hz | upper bass | the main speakers |
Play 60, 80, 100 and 120 Hz one after the other, from your seat. The loudness should stay about the same. If the sound drops around 80–100 Hz:
- Try the phase switch on the subwoofer (0° or 180°) and keep the setting where the bass is stronger.
- Check that the crossover is not set twice — on the receiver *and* on the subwoofer. Set it in one place, and turn the other one to its highest setting or to "LFE".
- Move the subwoofer a little. Bass changes a lot with the place in the room.
Find a good place for the subwoofer
Bass is uneven in a room. In some spots it booms, in others it almost disappears. A simple trick:
- Put the subwoofer at your seat for a moment, on the floor.
- Play 40 Hz or 50 Hz, or the sweep, at a medium volume.
- Walk or crawl along the walls where the subwoofer could go. Where the bass sounds strongest and smoothest, put the subwoofer there.
Frequently asked questions
Why can I hear nothing at 20 Hz?
Your subwoofer may not reach that low — many stop between 25 and 40 Hz. Also, people hear 20 Hz very badly, even when it is there. Put your hand near the subwoofer: you may feel it move before you hear anything.
Can I test a subwoofer with my phone speaker?
No. The phone's own speaker cannot play deep bass. Connect the phone or computer to the system with the subwoofer — by cable, HDMI or Bluetooth — and play the tones through it.
Can this test damage my speakers?
A long, very loud low tone can damage a speaker, so start at a low volume and turn up slowly. Stop at once if you hear knocking, flapping or hard buzzing. Short tests at a normal listening level are fine.
Which wave shape should I use?
Use Sine. It is one pure tone, so you hear exactly the frequency on the screen. Square and sawtooth add higher tones that your main speakers will play too.
Is the frequency exact?
The browser makes the tone with its own audio engine, so it is very close to the number you see. Your amplifier and speakers can add some distortion, especially at high volume.
Does it work with a soundbar or a car stereo?
Yes, as long as the sound from this page goes to that system. A soundbar subwoofer usually gets its bass from the soundbar, so play the page through the soundbar.
Related tools
- Tone Generator — any tone from 20 Hz to 20,000 Hz, with a sweep
- Left Right Speaker Test — check that left and right are the right way round
- Bass Booster — make the bass of an MP3 or WAV stronger
- Noise Meter — see how loud the room is with your microphone
- Dog Whistle — the other end: high tones from 15 to 22 kHz
How to use it
- Set this page's Volume low before you start
- Press a bass tone, such as 50 Hz — it starts at once
- Press 40, 30 and 20 Hz to hear where the bass gets weak
- Press Start the sweep to glide from 20 to 200 Hz; press Stop the sweep when you hear a rattle or the bass comes in
- Use −1 Hz / +1 Hz or the slider to fine-tune, and press Stop when you are done
