Poor Call Quality: Causes and Fixes

Poor call quality — choppy audio, muffled voices, one-second delays, or calls that drop mid-conversation — resolves with a targeted fix once the cause is identified. The cause almost always falls into one of four categories: signal conditions, a missing or misconfigured VoLTE or Wi-Fi Calling setting, a device hardware issue, or a network-level condition. This guide covers each category in order of how often it is the actual cause.

Key points:

• Weak signal (RSRP below −100 dBm) is a common contributor to choppy and dropped calls on modern LTE networks; the threshold is operator-dependent, and consistent degradation is typically observed below −110 dBm
• VoLTE must be enabled and registered for HD-quality voice; a phone on 3G fallback gets narrowband audio
• Wi-Fi Calling routes calls over a Wi-Fi connection using the same IMS core as VoLTE — it is the most effective fix for poor indoor coverage
• 3G network shutdowns in the US, Japan, Australia, and UK mean devices without VoLTE support cannot make calls at all on those networks
• Echo and muffled audio are usually hardware or acoustic issues, not network problems

For background on how VoLTE and VoNR work technically, including IMS, QoS bearers, and the 3G shutdown context, see VoLTE and VoNR Explained.

Check Signal Strength First

Signal quality is the primary variable in voice call quality on any cellular network. A VoLTE call uses a dedicated QCI 1 bearer with a 100 ms target packet delay budget and guaranteed bit-rate — but if the radio signal itself is weak or noisy, packets are lost before they reach the network, and the dedicated bearer cannot compensate.

How to check signal strength in dBm:

On iPhone, dial *3001#12345#* to open field test mode (iOS 16 or later; availability of individual metrics like RSRP varies by iOS version). The RSRP (Reference Signal Received Power) value indicates signal strength: −80 dBm or better is strong, −80 to −100 dBm is acceptable, below −100 dBm is weak and may cause audio artifacts; consistent degradation is typically observed below −110 dBm.

On Android (Pixel), go to Settings → About phone → SIM status → Signal strength. On Samsung, the same reading appears at Settings → About phone → Status → SIM card status → Signal strength.

Signal bars on the status bar are not a reliable indicator of VoLTE call quality, because bars represent a rough range and do not reflect signal-to-noise ratio or packet error rate.

What weak signal causes on voice calls:

VoLTE audio uses the AMR-WB (Adaptive Multi-Rate Wideband) codec, which adjusts its bitrate (between approximately 6.6 kbps and 23.85 kbps) in response to channel conditions. At very weak signal, the codec shifts to lower bitrates, producing audible quality degradation. At severe packet loss, audio becomes choppy or robotic even at the lowest codec rate.

Practical fixes for weak signal:

• Move to a location with better coverage: near a window, outside, or to a higher floor
• Enable Wi-Fi Calling (covered below) to route the call over Wi-Fi when cellular signal is inadequate
• Contact your carrier if the poor-signal area is your home or regular workplace — carriers maintain coverage improvement request processes

Verify VoLTE Is Enabled and Registered

VoLTE must be both supported by the device on your carrier’s network and enabled in settings. A device making calls without VoLTE active will either fall back to 3G circuit-switched voice (if 3G is still available) or be unable to make calls at all (if 3G has been shut down). 3G fallback produces narrowband audio (8 kHz sampling, 3.1 kHz audio bandwidth) — noticeably worse than VoLTE HD Voice (16 kHz sampling via AMR-WB).

How to check VoLTE status:

On iPhone, go to Settings → Cellular → tap the active SIM line → Voice & Data. The option should be set to LTE or 5G, not 3G. A “VoLTE” or “HD Voice” indicator in the status bar during an active call confirms IMS registration is successful.

On Android (Pixel), go to Settings → Network & internet → SIMs → tap the SIM → “Enhanced 4G LTE Mode” or “VoLTE” toggle. The exact label varies by Android version and carrier. Confirm the toggle is on.

On Android (Samsung), go to Settings → Connections → Mobile networks → VoLTE calls. Enable the toggle if it is off.

If the VoLTE toggle is missing or greyed out:

A missing VoLTE option most often means the carrier’s IMS profile is not present on the device. This is common on:

• Phones purchased in a different market from where the SIM is used
• Older or budget Android devices that were not certified for the carrier
• MVNOs where the host carrier’s IMS profile is required but not included in the MVNO’s device list

Check your carrier’s approved device list or IMEI compatibility checker. If your device is not listed, the carrier has not certified it for VoLTE on their network. See VoLTE and VoNR Explained for a full explanation of IMS profile requirements and how to verify compatibility.

Enable Wi-Fi Calling for Indoor Coverage

Wi-Fi Calling (formally VoWiFi — Voice over Wi-Fi) routes calls over a Wi-Fi connection using the same IMS core as VoLTE. The call travels through an IPsec tunnel to the carrier’s ePDG (evolved Packet Data Gateway), then into the IMS, where it is handled identically to a VoLTE call. Audio quality, codec, and caller ID are the same.

Wi-Fi Calling is the most effective countermeasure for poor indoor cellular signal. Concrete walls, underground spaces, and building materials that attenuate radio frequencies have no effect on a Wi-Fi connection from an indoor router.

How to enable Wi-Fi Calling:

On iPhone, go to Settings → Cellular → tap the active SIM line → Wi-Fi Calling → turn on “Wi-Fi Calling on This iPhone”. The status bar shows “Wi-Fi” next to the carrier name when a call is being routed over Wi-Fi.

On Android (Pixel), go to Settings → Network & internet → SIMs → tap the SIM → Wi-Fi calling → enable.

On Samsung, go to Settings → Connections → Wi-Fi Calling → enable.

Prerequisites:

• Your carrier must support Wi-Fi Calling and it must be enabled on your account
• The device must have the carrier’s IMS profile with the ePDG address configured (the same profile requirement as VoLTE)
• The Wi-Fi network must be stable; a congested or high-latency Wi-Fi connection will cause the same audio artifacts as a weak cellular signal

Emergency calls over Wi-Fi Calling:

When Wi-Fi Calling is active and the carrier supports it, emergency calls (such as 911 in the US or 112 in Europe) can be placed over Wi-Fi. Carriers that support this require a registered address for emergency location purposes. iPhone prompts for this address during Wi-Fi Calling setup. This is carrier-specific — confirm with your carrier whether emergency Wi-Fi Calling is supported.

For a detailed guide on Wi-Fi Calling setup, prerequisites, and international use, see Wi-Fi Calling (VoWiFi).

The 3G Shutdown and Its Impact on Call Quality

3G shutdowns are directly relevant to call quality because they affect which voice path the device uses.

Before VoLTE, 4G LTE devices made voice calls via CS Fallback (CSFB): the device temporarily dropped from LTE to 3G for the duration of the call. Once 3G is shut down, CSFB is impossible — there is no circuit-switched network to fall back to. A device without VoLTE support cannot make or receive calls at all on a post-3G-shutdown network.

Confirmed 3G shutdown dates for major markets (from carrier announcements):

If you are experiencing calls that work for data but produce no audio or fail entirely, and the device is older or was purchased for a different market, VoLTE incompatibility after 3G shutdown is the likely cause. See No Service on Your Phone? for the full diagnostic sequence when the device cannot register on the network at all.

Isolating Echo and Noise

Echo and background noise on voice calls have distinct causes depending on where the audio problem is heard.

Echo — Who Hears It

You hear your own voice echoed back: The echo is generated at the remote end. Their earpiece speaker is leaking audio into their microphone, and the network sends that captured audio back to you. This is called acoustic echo. Ask the other party to reduce their earpiece volume, switch to a headset, or move to a quieter location.

The other party hears an echo of their own voice: The echo is generated at your end. Your earpiece or speaker is leaking into your microphone. Solutions:

• Reduce your earpiece volume (the echo canceller in your device is overwhelmed at high volumes)
• Switch to a headset with an integrated microphone (places the microphone away from the earpiece)
• Do not use speakerphone unless in a quiet space — speakerphone on high volume almost always leaks acoustic echo

Most smartphones implement AEC (Acoustic Echo Cancellation) in the voice processing stack. AEC is effective within its design range, but it cannot cancel echo caused by the earpiece being pressed directly against a surface or by very high volume levels.

Background Noise

If the other party complains about background noise from your end, the fix depends on the noise type:

• Wind noise: move the microphone away from direct airflow; cup your hand around the device if needed. Many carriers use AMR-WB’s noise suppression features, but wind directly over the microphone exceeds what software suppression can remove.
• Constant hum or electrical interference: move away from sources of electromagnetic interference (motors, fluorescent lights, unshielded power cables). Check that the phone case does not cover the microphone opening.
• Room noise: enable noise suppression in your dialler app if available (some Android manufacturers include an “Enhanced noise cancellation” option in call settings), or move to a quieter location.

Check for Network-Level Issues (Calls vs. Data)

A useful diagnostic distinction: is the call quality problem confined to voice calls, or does it also affect data?

Poor voice quality but normal data speeds: This pattern points to a VoLTE-specific issue rather than general radio conditions. VoLTE uses a dedicated bearer (QCI 1), separate from the data bearer (QCI 9). Problems on the dedicated bearer that do not affect data can indicate:

• An IMS registration issue on your account (carrier-side, resolvable by contacting support)
• A codec mismatch between your device and the network (the network falls back to a lower-quality codec)
• A carrier configuration issue — try a network settings reset (see below)

Poor voice quality and poor data speeds: Both using the same radio path means the problem is the signal itself. Follow the signal strength diagnostic steps in the first section of this guide. For a full walkthrough of diagnosing and fixing slow mobile data — including throttling, congestion, and MVNO-specific causes — see Slow Mobile Data Speeds.

Calls fail entirely but data works: A device registered for data but not for IMS cannot make VoLTE calls. This occurs after 3G shutdown on non-VoLTE devices, or when VoLTE is disabled in settings. See VoLTE and VoNR Explained for the IMS registration requirements.

Device Hardware Checks

Two hardware issues produce call quality symptoms that no network fix can resolve.

Microphone Obstruction

The primary microphone on most smartphones is a small aperture on the bottom edge of the device. Cases — particularly thick or poorly fitting ones — can partially or fully block it. Symptoms: your voice sounds muffled or the other party says you are very quiet.

Test: make a call with the case removed. If audio quality improves, the case is covering or dampening the microphone opening. Look for a case with a clearly cut opening at the microphone position.

Test: make the same call on speakerphone. If the other party hears you clearly on speakerphone (which uses the front-facing microphone on most devices), the bottom microphone is the issue.

Speaker or Earpiece Issues

If you have difficulty hearing the other party clearly even at maximum volume, and the problem persists with good signal and VoLTE active, the earpiece speaker may be partially obstructed by dust or debris. The earpiece grille on the top edge of the device is a common dust accumulation point.

Test: make the call on speakerphone or with a headset. If audio is clear through both, the earpiece opening is the problem. Clean the grille with a dry, soft brush. Do not insert objects into the grille.

Network Settings Reset

A network settings reset clears the device’s stored radio and carrier configuration, which can fix call quality issues that began after an OS update, a SIM change, or a software glitch affecting the modem’s carrier profile.

What it resets: saved Wi-Fi passwords, VPN configurations, Bluetooth pairings, APN settings, and cellular network preferences.

What it does not reset: eSIM profiles, apps, photos, contacts, or any personal data.

When it is worth trying:

• Call quality degraded immediately after an iOS or Android update
• Call quality degraded after switching to a new SIM or eSIM
• VoLTE was working previously but the IMS registration indicator has disappeared

Procedure:

On iPhone: Settings → General → Transfer or Reset iPhone → Reset → Reset Network Settings. The device restarts. Allow 30–60 seconds for network re-registration.

On Android (Pixel): Settings → System → Reset options → Reset Wi-Fi, mobile & Bluetooth. No full restart required; wait 30 seconds.

On Android (Samsung): Settings → General management → Reset → Reset network settings → confirm.

After the reset, check that VoLTE and Wi-Fi Calling are re-enabled in settings, as they may revert to defaults. For the full scope of what a reset affects and does not affect, see How to Reset Network Settings.

When to Contact Your Carrier

Contact your carrier’s support if:

• Call quality is poor regardless of location and signal strength, suggesting an IMS account-level issue
• Wi-Fi Calling cannot be enabled — the carrier may need to activate it on the account
• VoLTE indicator was working and has disappeared without any change on your end
• Call drops occur consistently in locations where you previously had good signal, which may indicate a tower configuration change

When contacting support, provide: your device model, IMEI (dial *#06#), the exact symptoms (choppy audio, echo, dropped calls), whether data works normally, and whether the issue occurs on Wi-Fi Calling as well as cellular. This information reduces back-and-forth and directs the agent to the correct team.

Frequently Asked Questions

Why does my call sound choppy or robotic?

Choppy or robotic audio during a VoLTE call is almost always caused by packet loss or high jitter on the radio path. The most common triggers are weak signal (RSRP below −100 dBm), moving through coverage gaps, or interference. Moving to a location with stronger signal or enabling Wi-Fi Calling typically resolves it.

The other party says my voice sounds muffled or distant. What should I check?

Muffled outgoing audio is almost always a device hardware issue: a blocked or dirty microphone opening. Check that the microphone is not obstructed by a case. Test by making a call with the case removed, or on speakerphone. If audio is clear without the case, the case is partially covering the microphone.

Why do I hear an echo during calls?

If you hear your own voice echoed back, the leak is at the remote end. If the other party hears an echo, the leak is at your end — reduce earpiece volume or switch to a headset. Speakerphone at high volume almost always produces acoustic echo. Most smartphones implement AEC (Acoustic Echo Cancellation), but it cannot cancel echo at extreme volume levels.

My calls drop at the same spot every day. Is there anything I can do?

Consistent drops at a specific location indicate a coverage gap there, not a device or plan issue. Enable Wi-Fi Calling so calls can continue over Wi-Fi when cellular signal is lost. You can also report the coverage gap to your carrier — most carriers have a coverage improvement request process via their website or app.

Does VoLTE use data from my plan allowance?

VoLTE uses a dedicated QCI 1 bearer separate from the general data bearer. Many carriers do not count VoLTE traffic against the monthly data allowance. However, carrier policies vary — check your carrier’s fair-use documentation for your specific plan.

Will resetting network settings fix call quality problems?

A reset can help if quality degraded after an OS update or SIM change. It clears Wi-Fi passwords, VPN configs, and Bluetooth pairings but preserves eSIM profiles. It will not help if the cause is signal strength, VoLTE incompatibility, or hardware.

Related Guides

• VoLTE and VoNR Explained — how voice calls work on 4G and 5G, IMS architecture, QoS bearers, and device compatibility requirements
• No Service on Your Phone? — step-by-step fix for when the device cannot register on the network at all
• Slow Mobile Data Speeds — How to Diagnose and Fix — diagnosing data speed issues including signal, throttling, and MVNO-specific causes
• Wi-Fi Calling (VoWiFi) — complete setup guide for calling over Wi-Fi, international use, and prerequisites
• How to Reset Network Settings (and What It Affects) — exact procedure for iPhone, Pixel, and Samsung, and what the reset does and does not clear