I have recently been playing with some very old Macs and emulators, which reminded me of how the Mac’s startup sound evolved over the years before going quiet in 2016. Ken from the Computer Clan made a nice video that provides a history of the startup sound and demonstrates how the startup sound changed over time.
When Apple disabled the startup sound by default in 2016, someone discovered that a Terminal command could bring it back:
sudo nvram BootAudio=%01
Unfortunately, that approach stopped working with Mac models in 2017, presumably due to Apple removing the option in a macOS update, and since then, new Macs have started up silently. Now, however, Twitter user DylanMcD8 has discovered a new NVRAM parameter that brings back the startup sound, even on the latest Macs.
sudo nvram StartupMute=%00
TidBITS Talk members report it working on 2017 iMacs, 2018 Mac minis, a 2018 13-inch MacBook Pro, and a 2019 16-inch MacBook Pro. However, AppleInsider said that it didn’t work on several machines—it’s unclear why not.
I don’t understand what modern-day Apple has against the startup sound. Sure, make it an option for those who need their Macs to be silent at all times, but it’s a useful indication that the Mac is working as expected—at least to that point in the boot process. Perhaps Apple is trying to encourage the belief that Macs are always available like iPhone and iPads, but reality doesn’t support that.
To reverse this setting, should you want to, change the command to:
sudo nvram StartupMute=%01
Thanks to Howard Oakley, whose post on his Eclectic Light Company blog was the first instance I saw of this, though it has subsequently spread widely.