Archive. This is an archive of the Apple Support Community. Discussions are being restored and soon you will be able to read and post here again.
darKnight27
User level: Level 1 (4 points)

iPhone 11 Bluetooth audio crackles and stutters when screen locks

I'm experiencing a really strange Bluetooth audio issue on my iPhone 11, currently running iOS 18.7.8.

Whenever I lock my iPhone's screen while listening to music through Bluetooth earbuds, the audio starts crackling and stuttering for approximately 5 seconds before returning to normal. Once those few seconds pass, the music plays perfectly fine.

Initially, I thought my earbuds were faulty, but I've experienced the exact same issue with two different pairs:

  • Oppo Enco 2
  • OnePlus Nord Buds 4

Some additional observations:

  • The issue happens primarily during my bus commute.
  • When the screen is unlocked and I'm actively using my phone, the audio generally works fine.
  • I listen to downloaded music, so it isn't related to internet connectivity or streaming.
  • I've used the same setup on the metro without experiencing this issue.

Troubleshooting I've already tried:

  1. Forgot both earbuds from Bluetooth settings and paired them again.
  2. Toggled Bluetooth off and on.
  3. Restarted the iPhone.
  4. Tested two different pairs of earbuds.
  5. Checked Bluetooth permissions under Privacy & Security.
  6. Disabled Live Speech and Vocal Shortcuts under Accessibility.
  7. Disconnected and forgot my smartwatch to rule out interference. The issue persisted.

The only things I haven't tried yet are resetting Network Settings and updating iOS.

I'm wondering whether this could be an iOS 18 Bluetooth bug, something related to how iOS handles Bluetooth audio when transitioning to the locked-screen state, or potentially a hardware issue with the iPhone 11.

Has anyone experienced anything similar? I'd particularly like to know whether resetting Network Settings or updating iOS has helped anyone with this kind of issue.

Any suggestions would be appreciated. I'd like to identify the cause of this issue before updating as im holding out due to performance concerns

Posted on Nov 4, 2026 9:10 AM

2 replies

tillu_code
User level: Level 4 (2,112 points)

Nov 4, 2026 4:34 PM in response to darKnight27

Since it only happens on the bus, I'd suspect radio interference from lots of phones and Wi-Fi around you. When the screen locks the phone tends to switch Wi-Fi and Bluetooth into a power saving mode, which is when the stutter shows up. Try turning Wi-Fi off during the commute (it's offline music anyway), and turn off Low Power Mode if it's on. Also try Settings > Wi-Fi and turn off Auto-Join Hotspot to see if it changes anything.

Lawrence Finch
User level: Level 10 (244,490 points)

Nov 4, 2026 12:41 PM in response to darKnight27

OK, if it happens during your bus commute it could be interference from the bus Bluetooth ticket scanner (if it has one). If it happens in certain locations it could be interference from other users of the Bluetooth band.


If it happens in specific places, and the same places every time, it is almost certainly microwave interference→Resolve Wi-Fi and Bluetooth issues caused by wireless interference - Apple Support. The frequency range used by Bluetooth is in an unlicensed band, and is also included in S band (2 to 4 GHz) radar. Uses include airport surveillance radar, air traffic control radar, surface ship radar, weather radar and ground penetrating radar. So if you are near an airport, body of water when larger boats and ships are present or you are near weather stations that is a likely cause. Bluetooth’s 2.4 GHz is right in the middle of S band.

Originally posted at discussions.apple.com/thread/256388779