Studio Display speakers crackle briefly when Mac wakes from overnight clamshell sleep

[Owen Parker]

Every morning when I tap the keyboard to wake my M2 Max Mac Studio, audio through the Studio Display crackles for 2 seconds before settling down. Killing coreaudiod fixes it instantly — permanent firmware or sleep assertion workaround?

[Marcus Reed]

The crackle likely stems from a stale coreaudiod state serialized into the last APFS snapshot during the overnight maintenance window; when the Mac wakes, the audio server resumes from a snapshot where the Studio Display’s DSP firmware handshake was mid-negotiation. Run tmutil listlocalsnapshots / and delete any snapshots dated after the last clean boot with tmutil deletelocalsnapshots , then execute diskutil verifyVolume / and diskutil repairVolume / from Recovery to clear filesystem inconsistencies that can stall the audio driver’s power-state transition. If Time Machine is backing up to a network share, exclude /Library/Preferences/Audio and ~/Library/Preferences/com.apple.audio.* from the backup set to prevent preference corruption on restore.

Mac mini M4 Pro (48GB) | Studio Display

Chicago, IL | "Local Time Machine snapshots save every .0 upgrade week."

[Sarah Mitchell]

The Studio Display runs a bridged iOS variant (audioOS) that manages its A13-driven DSP — the crackle is a known symptom of the display’s firmware failing to re-establish the I2S/TDM clock sync over the Thunderbolt/USB-C link after deep sleep. Force a display firmware re-flash by putting the Studio Display into DFU mode (hold the power button 10s while plugging in, release when the LED pulses amber) and restore via Apple Configurator 2 on a second Mac; this rewrites the audioOS partition and clears the DSP’s NVRAM clock-calibration tables. Simultaneously, run system_profiler SPUSBDataType -json on wake to verify the display’s USB-C billboard device enumerates with bcdDevice 0x0200 (Thunderbolt 4) and not 0x0100 (USB4 fallback), which halves the isochronous bandwidth and causes buffer underruns.

iPhone 16 Pro (256GB, iOS 26) | iPad Air M2

Austin, TX | "Always try Finder Update before touching Restore."

[Claire Bennett]

Error 4013/9 analogs appear in log show --predicate 'subsystem == "com.apple.iokit.IOUSBHostFamily"' --last 1h as kIOUSBHostErrorCommunicationErr during the PD 3.0 SPR/APDO renegotiation when the Mac Studio wakes and requests 96W from the display’s upstream port — the display’s PD controller briefly drops the VBUS rail, starving the A13’s audio PLL. Disable Finder’s “Sync this iPhone over Wi-Fi” equivalent for the display by running defaults write com.apple.finder DisableDisplayFirmwareSync -bool true and reboot, which stops AMPDeviceDiscoveryAgent from probing the display’s restore interface during wake. Finally, insert a Thunderbolt 4 certified cable (0.8m max) with active retimers; passive 1m+ cables fail the PD Structured VDM discover identity command at 40Gbps, forcing a fallback to USB3.2 that breaks the 24-bit/48kHz isochronous endpoint timing.

MacBook Pro 16″ M2 Max | iPhone 16 Plus

London, UK | "Swap the USB-C cable before blaming the logic board."

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