Playback issue with 48kHz / 24bit ALAC files on MacMini

I’m hearing constant terrible clicking when trying to play back any ALAC files that are 48kHz/24bit on a MacMini core set that is also set as a zone.

All of these files play just fine in iTunes on the same MacMini. If I stream them to other zones (Devialet Phantom/Denon/Marantz Airplay receivers) they stream fine.

Additionally ALAC 48kHz/16bit and 44.1kHz/24bit are fine on the local zone.

Possibly related, I also noticed that the zone will be flaky, occasionally disappearing while trying to play back these files (No Audio Zone selected) and errors in the Console that line up with the zone disappearing.

Dec  3 10:47:32 MacMini RAATServer[66026]: RAATServer(66026,0x70000c068000) malloc: *** error for object 0x7fe189484800: incorrect checksum for freed object - object was probably modified after being freed.
Dec  3 10:47:40 MacMini RAATServer[66040]: RAATServer(66040,0x70000635c000) malloc: *** error for object 0x7f84c4261a00: incorrect checksum for freed object - object was probably modified after being freed.
Dec  3 10:50:00 MacMini RAATServer[66049]: RAATServer(66049,0x700000778000) malloc: *** error for object 0x7fdeb21b0e00: incorrect checksum for freed object - object was probably modified after being freed.
Dec  3 10:56:44 MacMini RAATServer[66101]: RAATServer(66101,0x70000c6ef000) malloc: *** error for object 0x7f8173a4b200: incorrect checksum for freed object - object was probably modified after being freed.
Dec  3 10:58:30 MacMini RAATServer[66221]: RAATServer(66221,0x700002d90000) malloc: *** error for object 0x7fa8f90ce800: incorrect checksum for freed object - object was probably modified after being freed.

As a workaround I’ve set the DSP engine for local zone to downsample 48kHz files to 44.1kHz.

Set the local zone of your Mac mini to use Built-in Output, instead of System Output. Also, enable Exclusive Mode in the settings for Built-in Output.

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Wicked, that fixed everything. Thank you for the solution!

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