Speaker testing with test tones

Why test your speakers with tones

Music hides problems. A busy mix can mask a dead tweeter, a swapped channel, or a cabinet that buzzes at one specific note. A clean test tone removes all that camouflage: you play one known frequency at a time, and anything that sounds wrong is the equipment, not the recording.

TestTones generates every signal in your browser using the Web Audio API, so there is nothing to install and nothing downloaded. You get a precise sine wave at any frequency from 1 Hz to 22,000 Hz, a sweep that glides across the whole range, and dedicated buttons for the four checks that catch most speaker faults.

The four checks that matter

1. Channel balance (left and right)

Open the speaker test and use the stereo balance test. Play "Left only," then "Right only," and confirm sound comes from the correct side at a similar level. If the labels don't match the speakers, your cables or source are swapped. If one side is noticeably quieter, check the balance control on your amp or operating system before blaming the driver.

2. Polarity and phase

Use the polarity / phase test. The in-phase signal should sound full, solid, and centered between the speakers. The out-of-phase (inverted) signal sounds hollow, thin, and oddly hard to locate, with the bass falling apart. If "in-phase" is the one that sounds wrong, one speaker is wired backward - swap the + and - terminals on that speaker.

3. Frequency response with a sweep

Go to the sweep section, set the start to 20 Hz and the end to 20,000 Hz, pick logarithmic (it spends equal time per octave, matching how we hear), and use a 20 to 30 second duration. Listen at a moderate, steady volume. The level should stay roughly even. Sudden loud spots are resonances; missing ranges are roll-off - many small speakers simply stop below 80 to 100 Hz.

4. Distortion and buzz hunting

Distortion shows up as a fuzzy, gritty edge instead of a pure tone, and it usually gets worse as you raise the volume. To find a mechanical buzz, set a single frequency in the main generator and nudge it with the +1 and +0.1 Hz buttons until the rattle peaks - that tells you which driver or surface is loose. Switching the generator from a sine to a square wave adds harmonics and makes a struggling tweeter easier to expose.

How to run a full speaker test

• Start quiet: set the volume slider low before you press play, then raise it gradually. Test tones are more revealing - and more fatiguing - than music.
• Confirm both channels: run the stereo balance test first so you know each side works before judging anything else.
• Check polarity: compare in-phase and out-of-phase. Solid and centered means correct wiring.
• Sweep slowly: a 20 to 30 second logarithmic sweep from 20 Hz to 20 kHz makes peaks and dips easy to hear.
• Hunt one tone at a time: for rattles, hold a fixed frequency and fine-tune in 0.1 Hz steps to pin down the buzz.
• Use pink noise to compare: the speaker test includes a pink noise button - a great quick reference because its energy is balanced across octaves.

Headphones vs. speakers

The same tools work for both, but the goal shifts. With headphones, the channel and balance checks matter most - you are confirming each earcup plays cleanly and at a matched level, with no buzz from a loose driver. Phase tests are less meaningful on headphones because each ear is isolated.

With speakers, room acoustics enter the picture. A dip you hear during the sweep might be the room, not the speaker - try moving your head or the speaker a foot and listen again. For bass-specific problems, the dedicated low-frequency walkthrough on the subwoofer and bass testing page goes deeper.

Common questions

Can test tones damage my speakers?

At normal listening levels, no. The risks come from very low frequencies at high volume (excess cone movement) and from driving an amp into clipping, which sends extra high-frequency energy to tweeters. Start quiet, raise gradually, and stop if you hear distortion.

My laptop speakers sound terrible on the sweep. Are they broken?

Probably not. Most laptop and phone speakers can't reproduce anything below 100 to 150 Hz and roll off at the top too. That's a size limitation, not a fault. For a fair test, use the speakers or headphones you actually care about.

What's the difference between a linear and logarithmic sweep?

A linear sweep changes at a constant number of Hz per second, so it races through the low octaves and lingers up high. A logarithmic sweep spends equal time per octave, which matches human hearing and is the better choice for judging response by ear.

Why does the out-of-phase test sound so strange?

When two speakers move in opposite directions, their low frequencies partly cancel in the air between them. You lose bass and the sound seems to come from nowhere in particular. That hollow effect is exactly why a polarity check is worth doing.

Recommended gear