By Giacomo Martiradonna Monday 24 February 2020
February 24, 2020 update Update: The old command no longer worked due to an Apple update; the new one, shown below, compatible with the new models produced from 2016.
MacBook Pro and Air produced from 2016 onwards no longer reproduce the initial "boing" when turned on. Fortunately, there is a way to restore the old startup sound.
It happened yesterday: history, evolution and curiosity of the Mac startup sound
The famous Mac boot sound was not always the same; over the years it has evolved to become the "bong" that we all know, thanks to the efforts of an engineer and the whim of Steve Jobs.
Beyond the nostalgic afflatus, the Mac startup sound has a very specific function: it helps us understand in an instant that the self-diagnostic test have been successful and that the computer is operating as it should. And then, a feature that has been there for 25 years, and you can't throw away 25 years of habits like nothing.
The good news that that heavenly deal can be restored with a simple command. just open the Terminal app you find in Applications> Utility and copy this string:
sudo nvram StartupMute =% 00
Enter, enter the administrator password and you're done. At the next reboot, the Mac will sing again. And if, for some reason, you want to go back, don't worry; just enter this other string to cancel the effects of the previous one:
sudo nvram StartupMute =% 01
Note: the old string "sudo nvram BootAudio =% 01" has not been effective for some time, while this new one works without problems. Simple, painless, and effective. Have fun.