A Galaxy S20 whose microphone seems dead or faint during calls most often has a blocked opening, a muting feature or a software fault, and the order is the same as for other Android phones. The S20 has microphones on the bottom edge, at the top and near the camera, so a case or lint covering one of them muffles your voice.
The checks in more detail
Remove the case, brush the openings and test with Samsung's Voice Recorder or the Samsung Members app's diagnostics. If a recording is clear, the hardware works and the cause is the call: a Bluetooth device taking over, or an app without microphone permission. In calls, Samsung's Noise Cancellation setting can clip a quiet voice, and turning it off is a quick test. Restart, and after an update wipe the cache partition. A silent recording means the microphone needs service.
If your voice is faint only on speaker mode, the issue is echo cancellation, not the microphone, so test the same call at the ear. If your voice is faint only in one video app, check that app's own input settings, which can be set to a different microphone. Samsung Members also lets you send an error report with the phone's logs, which Samsung's support can read if a repair is needed.
On the S20 the main call microphone sits on the bottom edge beside the USB-C port, a second one is at the top near the earpiece, and a third is next to the rear camera for video, so a charger plug or a thick case that sits over the bottom edge muffles calls specifically. The 5G models also have a different internal layout from the 4G ones, so a repair shop will ask which variant you own.
Differential
Likely causes of “Samsung Galaxy S20 family microphone is quiet, muffled or not working”, and how to tell them apart
- 1
A blocked opening or case
What separates it Voice is faint
How to confirm Remove the case and brush the openings
- 2
Bluetooth taking the call
What separates it Callers hear nothing
How to confirm Turn Bluetooth off
- 3
App permission off
What separates it One app cannot use the mic
How to confirm Settings, Apps, the app, Permissions, Microphone
- 4
Noise cancellation clipping
What separates it Quiet voices are cut
How to confirm Turn off Noise Cancellation in call settings
- 5
A hardware fault
What separates it The recording is silent
How to confirm Contact Samsung
Before you touch a setting
Record this first — changing settings destroys the evidence
- Whether Voice Recorder captures your voice
- Whether Bluetooth is connected
- Which apps fail
- Whether the case covers the openings
Try in this order
0 of 11 completedRecord with Voice Recorder
ReversibleSpeak at the bottom of the phone and play it back.
Turn off Bluetooth
ReversibleTest a call without a headset.
Remove the case and clean the openings
ReversibleUse a soft brush.
Check permissions
ReversibleSettings, Apps, Permissions, Microphone.
Turn off noise cancellation
ReversibleIn the call's settings.
Restart and wipe the cache partition
ReversibleThen test again.
Test at the ear and on speaker
ReversibleMake the same call both ways to see whether the problem is limited to speaker mode.
Check the app's own settings
ReversibleIn video apps such as Zoom or Meet, open the audio settings and choose the phone's microphone as the input.
Run the Samsung diagnostic
ReversibleSamsung Members, Phone diagnostics, Microphone, to test the hardware.
Send an error report if it persists
ReversibleSamsung Members, Get help, Error reports, so that Samsung can see logs.
Check the charging port for lint
ReversibleThe bottom microphone is next to the USB-C port, so pocket lint that fills the port area can muffle your voice as well as block charging.
Model-specific
What is true of this model and not of its siblings
- Multiple microphones
- The S20 has several, so one blocked opening matters.
- Noise cancellation
- It can clip quiet voices.
- Speaker mode
- Echo cancellation can clip a quiet voice.
- Third-party apps
- Some apps choose the wrong microphone.
- Dust
- Pocket lint in the bottom openings dulls a voice slowly.
- Error reports
- Logs help the repair desk see the fault.
- Three microphones
- The S20 uses the bottom, top and rear microphones for calls, recording and video, and each can fail separately.
- 5G and 4G variants
- The two variants differ internally, so name yours when you contact Samsung.
Stop boundary
When this stops being a self-service repair
- !If the recording is silent after a restart and cache wipe, contact Samsung
- !If only one app fails, contact its developer
- !Water exposure needs service
Evidence ledger
Sources behind this answer
Exact questions
Common questions
Why can't people hear me on my S20?+
A blocked opening, Bluetooth or a setting.
How do I test the microphone?+
Voice Recorder.
Does the case matter?+
It can cover the openings.
Does Samsung have a microphone test?+
Yes, in Samsung Members diagnostics.
Why is my voice faint on speaker?+
Echo cancellation.
Can Samsung see my logs?+
With your permission, through Samsung Members.
Where is the S20's main microphone?+
On the bottom edge beside the USB-C port.
Does a case affect call quality?+
A case that covers the bottom edge can muffle your voice.