Chime

The startup chime used in Mac computers indicates that the Mac successfully passed the diagnostic tests at startup.

macOS Catalina or older
To disable the chime, type in the following Terminal command: To enable the chime, type in the following Terminal command:

macOS Big Sur or newer
Since macOS Big Sur, the startup chime is again turned on by default. To modify it, choose Apple Menu ->, then click. In the Sound Effects pane, use the “Play sound on startup” setting to turn the startup sound on or off.

Regular Intel Macs
The startup (and attach) chimes are located in the UEFI firmware. To extract it, use UEFITool. Then, search for the BootChimeAudio section. Finally, extract the Raw Section inside it by right clicking on it, and selecting. Since it is a CoreAudio file, make sure to add the .caf extension on the file. The similar method applies to the attach chimes, but the section has no codename on it. To easily look for the chimes, after opening the UEFI firmware in UEFITool, select  ->. From here select  and search for. Make sure to disable the Unicode option. On T2 Macs, the UEFI Firmware contains the older 1998 chime. The chimes are CoreAudio (CAF) files with the following attributes: 16-bit, Mono at 44100 Hz with the IMA QT ADPCM Audio (ima4) codec.

T2 Macs
On T2 Macs, the chime is located in bridgeOS in. While it has the .aiff extension the chime is actually encoded in the Apple Lossless Audio Codec (ALAC) in a CoreAudio (.caf) container. The attributes are: 16-bit, Stereo at 48000 Hz with ALAC. On Macs with bridgeOS 4.6 or earlier, the boot chime file name is the same, but the file is in an Audio Interchange File Format (AIFF) container and the attributes are different: 16-bit, Mono at 24000 Hz in the IMA QT ADPCM Audio (ima4) codec. The charging chime is stored in. It is in an AIFF container with the following attributes: 16-bit, Stereo at 44100 Hz in the twos codec.

Apple Silicon Macs
Apple Silicon Macs use raw audio files to play the startup/charging chime. They are located in the macOS IPSW in Firmware/embeddedaudioresources/image4. To extract them, first extract the img4 header, and from here, open Audacity, click  ->   ->   and specify the parameters. To export, click  ->   ->. Some devices use the same chime despite being put into separate files. The parameters:
 * (j274/j375c/j375d)-boot-chime.im4p:.
 * (j293/j413/j493)-(attach/boot)-chime.im4p:.
 * (j313)-(attach/boot)-chime.im4p:.
 * (j456/j457)-boot-chime.im4p:.
 * (j314c/j314s/j316c/j316s)-(attach/boot)-chime.im4p:.