The Galaxy S21 has stereo speakers, with the earpiece at the top acting as the second one, and its speaker complaints on the Samsung Community concentrate on crackling, buzzing and a top speaker that goes quiet. Owners of the S21 series describe it on the top speaker especially, and they have found a surprising list of causes and fixes. The most unusual is physical: the phone is sealed for water resistance, so a sharp change of air pressure, such as a flight, a mountain road or a hot day, can leave the speaker distorted, and removing and reinserting the SIM tray lets the pressure equalise.
Samsung's own page for a speaker that does not work properly starts with volume, mute and Do Not Disturb and then asks you to run the speaker test in Samsung Members, Support, Phone diagnostics.
The checks in more detail
Owners also use the hidden test code *#0*# to open the hardware test menu and play the speaker test, which some say clears crackling. A case that covers the speaker grille, a protector over the earpiece slot, and dust in the grille all muffle sound, and a soft brush helps. Update the software, clear the cache of the video apps that crackle and test in Safe mode. If the diagnostic reports a fault, a service center should replace the speaker. Also test the speaker with a phone call in speakerphone mode: the call audio uses a different path from media, and if calls are fine and media crackles, an app or effect is the cause rather than the hardware.
The cache of the media app such as YouTube is a frequent suspect, and clearing it takes seconds.
Differential
Likely causes of “Samsung Galaxy S21 speaker is quiet, distorted or has no sound”, and how to tell them apart
- 1
Air pressure trapped in the sealed body
What separates it Crackle after a flight or a drive over a pass
How to confirm Eject the SIM tray and push it back in
- 2
A case or protector over the grille
What separates it Sound is muffled at the top
How to confirm Remove them and test
- 3
Dust in the earpiece grille
What separates it The top speaker is quiet
How to confirm Brush the grille gently
- 4
An app or effect
What separates it Crackle only in video apps
How to confirm Clear that app's cache and test in Safe mode
- 5
A failing speaker
What separates it The diagnostic reports a fault
How to confirm Samsung service
Before you touch a setting
Record this first — changing settings destroys the evidence
- Whether the crackle is top, bottom or both
- Whether it began after a flight or a climb
- The result of the Samsung Members speaker diagnostic
- The case and protector in use
Try in this order
0 of 8 completedRun the speaker diagnostic
ReversibleSamsung Members, Support, Phone diagnostics, Speaker.
Open the hardware test
ReversibleDial *#0*# and tap the speaker test to see which speaker works.
Eject and refit the SIM tray
ReversibleUse the ejector tool, remove the tray and push it back fully.
Remove case and protector
ReversibleTest the bare phone.
Clear the app's cache and use Safe mode
ReversibleTo rule out an app.
Update the software
ReversibleSettings, Software update.
Test speakerphone calls
ReversibleTo check a different path.
Clear the media app's cache
ReversibleIf only one app crackles.
Model-specific
What is true of this model and not of its siblings
- Stereo pair
- The top earpiece acts as a speaker.
- Pressure
- Owners link crackle to altitude changes.
- Different paths
- Calls and media use different paths.
- App caches
- They can cause crackle.
Stop boundary
When this stops being a self-service repair
- !If the Samsung Members diagnostic reports a speaker fault, book a service visit
- !If the sound is silent in Safe mode, contact Samsung
- !Crackle at every volume after the pressure trick needs repair
Evidence ledger
Sources behind this answer
Samsung's own steps for a speaker with no or poor sound.
S21-series owners describing crackling and the fixes tried.
The top speaker crackling on an S21-series phone.
Sound faults on an S21-series phone.
Pressure, case and software causes of a crackling Samsung speaker.
Exact questions
Common questions
Why does my S21 speaker crackle?+
Pressure, a blocked grille, an app or a fault.
What does the SIM tray trick do?+
It lets trapped air escape.
What is *#0*#?+
A hidden hardware test menu.
Is the S21 water resistant?+
Yes, which seals it.
Why do calls sound fine but media crackles?+
An app or effect.
Can YouTube cause crackle?+
Its cache can.
speaker: model differences
Also covered: Samsung Galaxy S26; Samsung Galaxy S21 family; Samsung Galaxy S20 Ultra family.