Bass test

A sweep from 20 Hz up. Stop it the moment you hear something, and that point is where your low end really begins.

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Turn your volume to about a third before you start. Tones are louder than music.

  1. Bass sweep

    A tone climbing from 20 Hz to 200 Hz. Stop it the moment you first hear it — that point is roughly where your speakers give up on low end.

Why sweep upwards instead of downwards

Starting at 20 Hz and climbing means the first thing you hear is the answer. Sweeping down from a comfortable frequency does not work nearly as well, because the tone fades out gradually and you end up guessing at the point where it disappeared into the noise floor of the room. Upwards has a clear moment of arrival.

Keep the volume moderate throughout. Low frequencies demand the most excursion from a driver, so this is the one test where an enthusiastic volume setting can actually cause damage. If you hear a knocking or slapping sound rather than a tone, stop: that is the voice coil hitting its limit.

What your result means

You first heard it atThat is typical of
20–30 HzA subwoofer, or large floorstanding speakers in a good room
35–50 HzFloorstanders, or capable bookshelf speakers close to a wall
50–80 HzBookshelf and studio monitor speakers
80–120 HzDesk speakers and small powered monitors
150–250 HzLaptop speakers — normal, not a fault
Above 300 HzPhone speakers, or a problem worth investigating on anything larger

Headphones are a special case: even small in-ear models usually produce output well below 40 Hz, because they seal against the ear and do not have to fill a room. If your headphones show a high starting point, check the seal and the tips before anything else, since a leaking seal loses bass first.

The room is part of the result

A 40 Hz wave is about eight and a half metres long, which is larger than most rooms. Waves that size reflect off the walls and interfere with themselves, producing positions where a frequency is loud and positions where it nearly vanishes. Move a metre and run the sweep again; if the result changes noticeably, you have measured the room as much as the speaker.

This is also why a speaker pushed against a wall sounds heavier. The wall reinforces the low frequencies, typically adding several decibels below 100 Hz. It is a free bass boost and also the reason a speaker can sound boomy in one position and thin in another.

Using the result

If you are setting a crossover between speakers and a subwoofer, put it slightly above the point where the main speakers stop rather than exactly at it. A crossover at 80 Hz with speakers that give up at 90 Hz leaves an audible hole.

If you are equalising, resist the temptation to boost below your speaker's limit. Raising 40 Hz on a speaker that produces nothing at 40 Hz makes no bass and plenty of distortion, because the driver still tries to move. Cutting a boomy region is almost always more effective than boosting a missing one.

For a single sustained low tone, use the tone generator and set it by hand; for the whole picture, the full sound test adds the channel and top-end checks, and the hearing range test covers the other end of the spectrum.

Frequently asked questions

How do I test the bass on my speakers?

Sweep a tone upwards from 20 Hz and stop it the moment you first hear anything. That point is roughly where your speakers begin to produce usable output. The test above does the sweep and reports the frequency you stopped it at.

What frequency is bass?

Sub-bass runs from about 20 to 60 Hz and is felt more than heard. Bass proper runs from about 60 to 250 Hz and carries the kick drum and bass guitar. Below 20 Hz is infrasound, which a speaker may move air at but which you will not hear as a pitch.

How low should my speakers go?

It depends entirely on driver size. Phone speakers start around 400 Hz, laptop speakers around 150 to 250 Hz, desk speakers around 80 to 120 Hz, bookshelf speakers around 50 to 70 Hz, and a subwoofer 20 to 30 Hz. If your result is in the right band for your hardware, nothing is wrong.

Why can I feel the bass but not hear it?

Below roughly 30 Hz, perception shifts from pitch to pressure and vibration. Your body senses the movement through the chest and through objects in the room before the ear registers a note. That is normal and is why cinema systems put so much effort into that band.

What is a good test tone for a subwoofer?

Start at 40 to 50 Hz to check it is producing at all, then step down to 30 and 25 Hz. A sine wave is the right choice: a square wave at those frequencies contains a lot of energy higher up and will make a subwoofer sound as though it reaches lower than it does.

Can bass tones damage a speaker?

Yes, more easily than any other frequency, because the driver has to move furthest at the bottom of its range. A loud sustained 25 Hz tone into a small speaker can drive the cone past its limit. Keep the level moderate and stop immediately if you hear a mechanical knocking sound, which is the coil bottoming out.

Why does my bass sound different in different parts of the room?

Room modes. Low frequencies have wavelengths of several metres, so they form standing waves that cancel in some positions and pile up in others. Moving half a metre can change the level at a given frequency by a large margin. That is the room, not the speaker.

How do I find a rattle caused by bass?

Use the tone generator, pick a square wave, and step slowly from 40 Hz to 200 Hz. Square waves excite harmonics and find rattles far more efficiently than sine waves. When the buzz appears, press on panels, grilles, shelves and nearby objects until it stops.

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