Subwoofer and bass test
Does your subwoofer work, and does anything rattle? Play a low tone and listen.
Press left, right or both to start. Space stops everything.
Sound
Phase
Two quick checks
Press the 40 Hz and then the 100 Hz button at a moderate volume. A working subwoofer should play both clearly, and 40 Hz should be felt as much as heard. If 40 Hz is silent, check the power, the cable, the level knob and the crossover setting.
Finding a rattle
If something buzzes at one of the tones, you have found a loose part, a resonance in a cabinet or shelf, or a port that is too close to a wall. Move the frequency slider slowly up and down: the rattle gets loud at one pitch and disappears at the others.
Small speakers
Laptop and phone speakers play little or nothing at 40 Hz, and that is normal. This page also cuts everything below 35 Hz on purpose, because those tones only move small speakers without making sound, so 40 Hz is the lowest check it offers.
Keep the volume moderate and stop at the first sign of distortion: long loud bass can damage speakers.
Questions
Why do my speakers crackle or buzz?
Lower the volume first: distortion at high volume is often the speaker reaching its limit. If it also crackles at low volume, try another cable, port or device, and keep the speakers away from power adapters and phones, which can add interference. Bluetooth speakers can crackle when the connection is weak or far away.
The scope helps to tell where the problem is. If the wave on the scope is smooth while you hear crackling, the page is sending a clean signal and the fault is further along: the system driver, the cable or the speaker.
Why can't I hear the lowest or highest tones?
Both your hearing and your speakers have limits. Many people hear from about 20 Hz to 20 kHz when they are young, and the top end fades with age. Small laptop and phone speakers often play very little below roughly 100 Hz.
This page also cuts tones under 35 Hz on purpose, because they only make small speakers move without making sound. A sweep that seems to start late or end early is therefore normal.
Is it safe for my speakers and my ears?
The page starts at a low volume, limits its maximum level, fades sounds in and out and filters out the deepest bass, which all helps. It cannot make a damaged or very small speaker safe, though.
Keep the volume moderate, avoid long loud tones in the lowest and highest ranges, and stop at the first sign of distortion: Space stops everything at once. Loud sound can also harm your hearing. You use the page at your own risk.
How can I test a subwoofer?
Press 40 Hz and then 100 Hz at a moderate volume. A working subwoofer should clearly play both. If you hear nothing at 40 Hz, check the power, the cable, the level knob and the crossover setting. If something rattles at one of the two tones, you have found a loose part or a resonance.
Tones under 35 Hz are cut on this page on purpose, so 40 Hz is the lowest check it offers.