Give me a reason I shouldn't roll this command out to our entire fleet of 2016+ Macs...

But seriously, how did this remain hidden for so long?

I knew it was in there somewhere!

This makes me unreasonably happy, and I'm ok with that :)

I like most of you was excited at this, but I activated this newly found capability on my MacBook Pro (2018) model and it sounded TERRIBLE and not terribly authentic. I’m tempted to try again on a different machine. My MacBook Pro’s sound is otherwise flawless. I had my hopes up.

Yes, same awful sound with mine 2018 MBP 15". But at least there's a startup sound... :-)

@bradtchapman It was first discovered back in 2016 when it was first removed, but the nvram flag changed somewhere along the line. This is really a celebration of the new StartupSound flag, since the BootAudio one doesn't work on the newer ones (I believe).

The sound for 2016 & 2017 T1's and 2018 & 2019 T2's is different.

The 2016/17 is the same exact sound as the macbook air or the 12" macbook.
The 2018/19 sounds deeper but might have some slight static.

If you tried this and it didn't work, make sure your sound is not muted. That usually fixes it for anyone having issues. Also make sure you type the command in exactly the same, as it's case sensitive.

Very cool. Thanks for posting. Worked on the 2018 MBP.