Direct answer
For the Samsung Galaxy S24, different apps and call modes use different microphones. First, record voice memo and front/rear video, then compare normal and speakerphone calls.
What this covers
- Samsung Galaxy S24 (SM-S921*)
- Samsung Galaxy family; S Pen, foldable display, DeX, USB moisture and One UI features vary by exact model.
- The specific fault this record addresses: microphone is quiet, muffled or not working
What it does not cover
- ×The same symptom on a different Samsung product line, which has its own record and its own cited source
- ×An on-screen error code whose meaning has not been checked against this exact model's manual
- ×Live electrical, gas, sealed-system, internal battery-cell or structural repair — a technician boundary, not a self-service step
Differential
What actually causes this, and how to tell them apart
These are ordered by how often each one is the answer, not by how easy it is to try. The point of the middle column is that two causes producing the same headline symptom rarely produce the same detail — that detail is what tells you which one you have before you change anything.
- 1
A case or grip covering a microphone port
What separates it One situation fails and the others are fine — usually speakerphone or video, where a microphone away from the mouth is doing the work. A case with a misaligned cut-out, or a hand across the bottom edge, is enough.
How to confirm Remove the case, hold the phone away from your palm, and repeat the same recording. This is free and it explains a large share of these.
- 2
Lint in the microphone port
What separates it Audio has become progressively quieter or more muffled over months rather than failing suddenly. The ports are small and they live in a pocket.
How to confirm Look into the ports with a bright light. Record a voice note before and after clearing gently with a soft dry brush.
- 3
An app does not have microphone permission
What separates it It fails in one app and works in the voice recorder. Permissions are revoked by updates, by privacy settings and by users who tapped 'don't allow' months ago.
How to confirm Check that app's microphone permission specifically. This is the first thing to check when the failure is app-shaped.
- 4
A Bluetooth accessory is capturing the audio
What separates it Callers cannot hear you and the phone seems fine, with an accessory connected somewhere — often in another room or a car outside. The call's microphone is on the accessory.
How to confirm Disconnect Bluetooth entirely and repeat the call. This is a very common cause of 'nobody can hear me' with no fault anywhere.
- 5
Noise suppression removing the wrong thing
What separates it Voice sounds thin, cut off at the start of words, or drops in and out in a quiet room. Aggressive noise cancellation can misjudge a quiet speaker.
How to confirm Compare a recording in a normal room against one outdoors. Where the phone offers a voice isolation setting, changing it is the test.
- 6
Water in the port
What separates it Muffled audio after rain, a shower or a spill, improving over hours or days. Water in the mesh damps the diaphragm without damaging it.
How to confirm Leave it port-down in moving air. Do not use heat and do not use rice.
- 7
A screen protector over the earpiece microphone
What separates it Calls held to the ear are affected while speakerphone is fine. A protector that covers the top slot muffles the microphone next to it.
How to confirm Check whether the protector's cut-out lines up with the slot.
- 8
The other end of the call
What separates it One person cannot hear you and everyone else can. Call audio has two ends and a network in between.
How to confirm Call someone else, and record a voice note locally. A clean local recording exonerates the phone completely.
Before you touch a setting
Record this first — changing settings destroys the evidence
Every item below stops existing the moment a reset, re-pair or settings change is made. Written down first, they are what separates the causes above; recovered afterwards, they are guesswork.
- Which situations fail and which work: handset call, speakerphone, video recording, voice note, and one specific app. Different microphones serve different situations.
- A voice note recorded locally, which tests the microphone without the network or the other party involved.
- Whether a case, grip or screen protector is fitted, and whether its cut-outs line up.
- Whether any Bluetooth accessory is connected, including ones out of the room.
- Whether the audio is quiet, muffled, cut off at the start of words, or absent — those describe different faults.
- Whether it changed suddenly or degraded over months.
- Whether the phone has been near water recently.
Record a voice note before anything else
ReversibleThis tests the microphone alone, with no network, no other party and no call software involved. A clean local recording exonerates the microphone entirely and moves the whole investigation to the call path or one app.
Map which situations fail
ReversibleHandset call, speakerphone, video, voice note and one app use different microphones in different combinations. One failing while others work is the single most useful fact here — it identifies which microphone, and it rules out the ones that work.
Disconnect every Bluetooth accessory and retry
ReversibleA connected accessory takes the call's microphone with it, including one in another room or a car parked outside. 'Nobody can hear me' with a perfectly working phone is this more often than any hardware fault.
Remove the case and keep your hand off the bottom edge
ReversibleA case with a misaligned cut-out, or a palm across the bottom microphone, is enough to muffle speakerphone and video while a handset call stays fine. Free to test, and it explains a large share of these.
Check the app's microphone permission
ReversiblePermissions are revoked by updates and by privacy settings, and a denial made months ago is invisible now. When the failure is confined to one app, this is the first thing to check and usually the last.
Inspect the ports under a bright light
ReversibleAudio that has become gradually quieter over months rather than failing suddenly is usually lint. Clear it with a soft dry brush — never a pin, never compressed air forced into the port, never liquid — and record the same voice note again to compare.
Test the same call to a different person
ReversibleCall audio has two ends and a network between them. One person unable to hear you while everyone else can is not your phone, and no amount of work on it will change that.
Compare a quiet room against a noisy one
ReversibleAggressive noise suppression can misjudge a quiet speaker and cut the start of words or drop the voice entirely. Where the phone offers a voice isolation setting, changing it and repeating the same recording is the test.
Dry the port properly if water is involved
ReversiblePort down, in moving air, for several hours. Water in the mesh damps the diaphragm without damaging it, so this usually recovers on its own — but heat drives moisture inward and rice leaves dust exactly where it does the most harm.
Model-specific
What is true of this model and not of its siblings
Generic advice for the product line fails here. Each item below is a property of this specific model family that changes which of the steps above apply to you.
- Model scope
- SM-S921*. Samsung Galaxy family; S Pen, foldable display, DeX, USB moisture and One UI features vary by exact model.
- Display
- 156.4mm (6.2" full rectangle) / 152.3mm (6.0" rounded corners), 2340 x 1080 (FHD+), Dynamic AMOLED 2X, up to 120 Hz. Samsung quotes two figures for screen size — the full rectangle and the rounded-corner measurement — which is why this phone is listed at two different sizes in different places and neither is wrong.
- Refresh rate
- Up to 120 Hz adaptive. A high refresh rate is one of the larger discretionary battery costs on this phone: it is genuinely smoother and it genuinely costs runtime, which is why battery complaints on this model are worth checking against the refresh-rate setting before anything else.
- Panel
- Dynamic AMOLED 2X. This is an AMOLED panel, so dark mode reduces consumption for real — black pixels are switched off rather than backlit — and a static bright element left on screen for very long periods is the one wear risk this panel type has.
- Rear cameras
- 50.0 MP + 10.0 MP + 12.0 MP. The main sensor is 50 megapixels, which produces substantially larger files than a 12-megapixel camera and is a meaningful contributor to how quickly storage fills.
- Zoom
- Optical Zoom 3x, Optical quality Zoom 2x (Enabled by Adaptive Pixel sensor). Zoom range is the practical difference between models in this line. A close-up that will not focus at the long end is normally the telephoto's minimum focus distance rather than a fault — taking the same shot at 1x confirms it in seconds.
- Video
- UHD 8K (7680 x 4320)@30fps. Resolution and frame rate dominate how quickly video fills storage and how hard the phone works thermally — sustained 8K recording is the single most common reason a Galaxy camera stops mid-take and warns about temperature.
- Memory and storage
- 8GB RAM with a 128GB storage tier. RAM matters directly to one symptom: apps reloading when you switch back to them is memory pressure rather than a crash, and it is more likely on the lower-RAM configurations.
- SIM
- SIM 1 + SIM 2 / SIM 1 + eSIM / Dual eSIM. Three combinations are supported, and the default line for calls, for messages and for cellular data are three separate settings — crossing them produces calls arriving on one number while data or messages use another, with almost no indication that anything is wrong.
- Wi-Fi
- 802.11a/b/g/n/ac/ax 2.4GHz+5GHz+6GHz, HE160, MIMO, 1024-QAM. This is Wi-Fi 6E hardware with 6 GHz support. A router running a newer standard falls back rather than refusing, so a difference against a newer phone on the same network is specification rather than fault.
- Bluetooth
- Bluetooth v5.3. Version affects range, reconnection behaviour and which accessory features are available — a newer accessory paired here operates at this version's capabilities rather than failing, which is regularly mistaken for a pairing fault.
- Connector
- USB Type-C. Note that a USB-C cable which fits is not necessarily rated for this phone's charging speed: USB-C carries several power profiles, and a data-oriented cable charges slowly or intermittently while seating perfectly.
- Processor
- 3.2GHz, 2.9GHz, 2.6GHz, 1.95GHz. Clock speed is not the useful number for troubleshooting; what matters is that sustained heavy work throttles, so performance measured while the phone is already hot is measuring the throttling rather than the phone.
- Samsung's own specification
- Samsung publishes the full specification for this model at samsung.com/uk/smartphones/galaxy-s24/specs/. Where any figure above matters to a decision, that page is the authority and this one is not.
- Biometric
- An in-display fingerprint reader, which looks through the screen. A thick or incompatible screen protector genuinely interferes with it, which is why unlock reliability often changes the day a protector is fitted rather than gradually.
- Modem
- 5G capable. In marginal 5G coverage the phone hands repeatedly between 5G and LTE, which costs more battery and generates more heat than settling on either — so the preferred-network setting is a real diagnostic lever rather than a preference.
- Charging
- Supports wireless charging. Coil alignment is tighter than it looks and a thick case, a metal plate or a card in the case defeats it entirely — so wireless charging failing while cable charging works is usually the case rather than the phone.
- Water resistance
- Rated water resistant, which is not waterproof and which degrades with age, drops and seal disturbance. The rating covers incidental exposure; it is not a guarantee, and moisture-detection warnings are deliberately conservative and can persist after the port feels dry.
- Platform
- Android, with a manufacturer interface layer over it. Battery optimisation and background-execution restrictions are applied per app and are far more aggressive than on iOS — which is why 'set this app to unrestricted' is a real fix here and has no equivalent elsewhere.
- Symptom boundary
- This record covers Samsung Galaxy S24 when it microphone is quiet, muffled or not working. A different symptom on the same hardware, or this symptom on a different Samsung product line, has its own record with its own causes and its own cited source.
Stop boundary
When this stops being a self-service repair
Continuing past any one of these costs more than the repair saves — in safety, in warranty, or in evidence a technician needs.
- !A local voice note is silent or badly distorted with the case off, the ports clear and no accessory connected — that is the microphone hardware.
- !The fault began after liquid exposure and has not improved after several days of drying.
- !The fault began after a drop, which can displace the microphone or its flex connection.
- !Every microphone on the phone fails simultaneously, which points at the audio subsystem rather than one component.
Evidence ledger
Sources behind this answer
Visible sources support the visible claims. Home Product Support records the publisher, the fact used and the review date; community reports can suggest an issue but do not become a published fact on their own.
Where the manufacturer's article stops. Samsung publishes this as "Microphone issues with Galaxy phone or tablet". Samsung's microphone troubleshooting article for Galaxy phones: quiet, muffled or non-functioning mic on calls and recordings. Probed 2026-08-21: title-verified. What that article does not carry is the model boundary — it is written for a product line, and SM-S921* is the scope applied here. Where a control label, terminal, indicator pattern or reset sequence differs on your unit, the manual for that exact model is the authority, not this page and not the article.
Exact questions
Common follow-ups
What size is the Galaxy S24 screen?+
Samsung lists 156.4mm (6.2" full rectangle) / 152.3mm (6.0" rounded corners), at 2340 x 1080 (FHD+). The two size figures are the full rectangle and the rounded-corner measurement — both are Samsung's own numbers, which is why this phone appears at two different sizes in different places.
Does the Galaxy S24 have a 120Hz screen?+
Yes, up to 120 Hz adaptive on a Dynamic AMOLED 2X panel. It is worth knowing for battery complaints specifically: a high refresh rate is one of the larger discretionary costs on this phone, and it is the first setting to check when runtime is disappointing.
Does dark mode save battery on the Galaxy S24?+
Yes, genuinely — it uses an Dynamic AMOLED 2X panel, where black pixels are switched off rather than backlit. The saving is real though smaller than reducing brightness or refresh rate, which remain the larger levers.
What cameras does the Galaxy S24 have?+
50.0 MP + 10.0 MP + 12.0 MP, with optical zoom 3x, optical quality zoom 2x (enabled by adaptive pixel sensor).
How much storage and RAM does the Galaxy S24 have?+
8GB RAM and a 128GB storage tier. The RAM figure is the one that matters for a specific symptom: apps reloading from scratch when you switch back to them is memory pressure rather than crashing, and it is more likely on lower-RAM configurations.
Does the Galaxy S24 support eSIM?+
Yes — Samsung lists SIM 1 + SIM 2 / SIM 1 + eSIM / Dual eSIM. Because more than one line can be active, check which line is set as the default for calls, for messages and for cellular data separately; those are three settings and crossing them is easy to do and hard to notice.
What Wi-Fi does the Galaxy S24 support?+
802.11a/b/g/n/ac/ax 2.4GHz+5GHz+6GHz, HE160, MIMO, 1024-QAM. That is Wi-Fi 6E with 6 GHz support; a router on a newer standard falls back rather than refusing, so a gap against a newer phone is specification rather than a fault.
Can the Galaxy S24 record 8K video?+
Yes — UHD 8K (7680 x 4320)@30fps. Bear in mind that resolution and frame rate dominate both how fast storage fills and how hard the phone works thermally, and sustained 8K is the most common reason a Galaxy camera stops mid-recording with a temperature warning.
What Bluetooth version is the Galaxy S24?+
Bluetooth v5.3. Version affects range, reconnection and which accessory features are available — a newer accessory paired here runs at this version's capabilities rather than failing, which regularly gets misread as a pairing fault.
Nobody can hear me on calls.+
Check for a connected Bluetooth accessory first — including one in another room or a car outside. A connected accessory takes the call's microphone with it, and the phone gives almost no indication that it has. This is more common than any hardware fault.
How do I test the microphone by itself?+
Record a voice note. That uses the microphone with no network, no other party and no call software involved. A clean recording exonerates the microphone completely and tells you the problem is in the call path or in one app.
It works on speakerphone but not on a normal call.+
Those use different microphones. A handset call uses the one near your mouth at the bottom, or the one by the earpiece; speakerphone uses a different combination. One working and the other not localises the fault precisely — and a screen protector over the top slot is a common cause.
My voice sounds muffled to other people.+
Two usual causes: something covering the port, or lint inside it. Take the case off, keep your palm off the bottom edge, and look into the ports with a bright light. Gradual degradation over months is lint; sudden onset is usually the case or an accessory.
It fails in one app only.+
Check that app's microphone permission. Permissions are revoked by updates and privacy settings, and a 'don't allow' tapped months ago is invisible now. The hardware is fine, since it works elsewhere.
The start of my words gets cut off.+
That is usually noise suppression misjudging a quiet speaker rather than a hardware fault. Compare a recording in a normal room against one outdoors, and change the voice isolation setting if your phone offers one.
How do I clean the microphone port?+
A soft dry brush, gently, with the phone powered off. Never a pin — the mesh is delicate and pushing debris through it is worse than leaving it. Not compressed air forced into the port, and nothing liquid.
It got muffled after I was caught in the rain.+
Water in the mesh damps the diaphragm without damaging it, and it usually recovers. Leave the phone port-down in moving air for several hours. Do not apply heat, which drives moisture further in, and do not use rice, which adds dust to the problem.
Only one person says they cannot hear me.+
Then it is very probably not your phone. Call audio has two ends and a network between them, and a single affected contact points at their end or the route. Test with someone else and record a local voice note to confirm.
Does this answer apply to every Samsung model?+
No. It is scoped to SM-S921*. Samsung Galaxy family; S Pen, foldable display, DeX, USB moisture and One UI features vary by exact model.
What should I record before troubleshooting microphone or can't hear me?+
Record the complete model identifier, exact message or indicator, software/firmware where visible, the operating stage and what still works.
Why is a factory reset not the first step?+
A reset can erase accounts, networks, maps, schedules or preferences without distinguishing microphone, can't hear me. The ordered checks preserve that evidence.
When should I stop and use qualified service?+
Do not insert tools or liquid into microphone openings.
Answer for the exact device and software version shown above.