Two seconds per side

iPhone Speaker Test: Check Each Side Separately

Played together, a healthy speaker covers for a failing one. Played one at a time, the problem is obvious in about two seconds.

The speaker test is free in Water Eject.

How the test works

Water Eject sends a steady 660 Hz sine tone to one channel only and holds it for about 1.3 seconds. Left, then right. There is nothing musical about 660 Hz: it sits in the middle of what a phone speaker reproduces well, it is loud enough to judge without being harsh, and it is short enough to repeat as often as you like.

Before you test

Case off. Screen protector corners checked. Bluetooth off, so the audio cannot leave the phone. A quiet room. Media volume around two thirds.

What to listen for

Loudness, cleanliness and whether the tone holds steady. Play left, then right, then left again. Your ear compares far better than it measures.

Reading the result

What each side tells you.
What you hear	What it usually means	Next step
Both sides equal and clean	The speakers are fine. The dullness is a setting, the source material or the audio route.	Work through the muffled sound checklist.
One side clean but noticeably quieter	Something is in the way: lint, a case lip, or moisture.	Clean the grille, or clear the water if it got wet.
One side buzzes or rattles	The membrane or its surround is damaged, or something loose is sitting against it.	Cleaning rarely helps here. Book a repair.
One side silent at every volume	A dead channel or a broken connection.	Restart once to rule out software, then book a repair.
The tone wobbles or cuts in and out	Liquid still moving in the opening, or a loose contact.	Dry the phone in air for a day, test again, then decide.

The input level meter, and what it is not

The Tools tab also carries a live input level meter. It turns on the microphone while it is on screen, reads the level of what comes in, and fills a bar between zero and one. It is genuinely useful for one job: play the same tone before and after cleaning, from the same distance, and watch whether the bar moves higher.

It is not a decibel meter. iOS hands apps a level relative to digital full scale, not a calibrated sound pressure level, and no phone app can turn one into the other without a reference. The bar is relative, and the app labels it that way.

The microphone runs only while the meter is open. Nothing is recorded, stored or sent anywhere.

Run the test yourself

Left, right, and a relative level meter, all free. The same app carries the low pulsed tone for water and a 2.2 kHz tone for dust.

Free. iPhone, iOS 17 or later.

Testing beyond one frequency

A single 660 Hz tone answers the question most people actually have: is one side worse than the other. If you want to know more, the Pro tone generator plays any frequency from 100 Hz to 16 kHz in 10 Hz steps. Sweeping it by hand shows where a speaker starts to rattle, which frequencies have gone thin, and whether the two sides diverge at the top of the range.

Keep the phone away from your ear above a few kilohertz. The app asks you to confirm that before it starts the tone generator, and it reduces the level automatically above 2 kHz, further again at 8 kHz and above.

Questions

How do I test my iPhone speaker?

Play a known tone through one side at a time and listen for a difference. In Water Eject the Speaker Test sends a 660 Hz tone for about 1.3 seconds to the left channel, then to the right, so a weak or silent side is obvious. Do it with the case off, at a moderate volume, in a quiet room.

Why test the left and right side separately?

Because an iPhone plays stereo through two different openings, the loudspeaker at the bottom edge and the earpiece above the screen. Played together, a good side masks a bad one and everything sounds acceptable. Played one at a time, a quiet or dead side stands out immediately.

Does the input level meter show decibels?

No, and it does not claim to. iOS gives apps a level relative to full scale, never a calibrated sound pressure level, so the meter shows a relative bar between zero and one. It is good for comparing before and after on the same phone in the same room. It is not a measuring instrument.