Mac Startup Chime Idiocy
Mac has a extreme idiotic startup sound. And it has became a cult.
you look at online, to see how to stop it, apparently it's nearly impossible.
the solution offered, is to type one of this command in terminal:
sudo nvram SystemAudioVolume=%80sudo nvram SystemAudioVolume=%01sudo nvram SystemAudioVolume=%00sudo nvram SystemAudioVolume=0sudo nvram SystemAudioVolume=''
however, it didn't work with my Mac. Digging deeper, you find that, different Macs have different value to disable the start up sound. Also, it may also disable your sound card.
you can do man nvram to read about what that command does.
type
nvram -p
to see all values
type
sudo nvram -d SystemAudioVolume
to set it back to default. (it basically remove this variable.)
in conclusion, apparently this sound is patented. Some say, it is dianostic sound and shouldn't be turned off. Some give the tip, that by pressing Mute button while the system starts, it won't make the sound. Some say, when shutting down, set volume to 0 and on start up Mac won't make the sound. (didn't work for me) Note, plug in a headphone doesn't work.
In the end, this is a incredible stupidity due to cult. Lots people do not want the sound. including me. It wakes up babies and roommates. The sound itself is extremly jarring. Of 1980's synth quality. Yet, Apple refuse to even provide a way to turn it off.
PS Apple killed the startup sound. Macs from 2016 and 2017 after, do not have the startup chime.