The startup sound runs before the OS is even booted - maybe even before the OS bootstrapping process starts. I remember being amused that they'd taken up space inside my incredibly packed C2D Mac Mini for a speaker whose sole purpose seemed to be to play this short audio clip. Not even one of those tiny piezo beeper things - a proper speaker capable of some volume!

> a speaker whose sole purpose seemed to be to play this short audio clip

Not at all. The internal speaker of a Mac will play any "system notification" sound effects.

Here's[1] the macOS audio mixer. I've right-clicked a source here. Notice the separate "Sound Output" and "Alerts and Sound Effects" choices here. By default, external speakers will be used for "Sound Output", but "Alerts and Sound Effects" will stay pinned to the internal speaker.

[1] https://i.imgur.com/2Z0GB04.png

The simplest way to notice this is to empty the Trash on a Mac Mini (or a Mac Pro.) The crumple sound comes from the computer!

I think the justification for this is that, even if you have an external set of speakers plugged into your computer, you might have them off. Apple wants the Mac to still be able to beep at you to get your attention, even if your speakers are off (just like a PC can with its PC speaker.)

(Of course, you can reassign the "Alerts and Sound Effects" to your regular audio source, if you want to be able to mute them as well.)

Also, fun fact: if you don't plug in any external audio sources—for example, if you plug in an HDMI monitor to a Mac Mini that has no HDMI audio support, and don't plug in an audio-out cable—then all audio will come out of the internal speaker. Try it! (This was a common "thing" in computer labs back in the Power Mac days. You'd try to watch a YouTube video, but the computer would just have a CRT and no speakers attached. So you'd hear tinny sound from the tower!)

I am recent convert to Apple and before I abandoned windows for Linux sometime around Vista, I would always disable every desktop sound as you do.

That being said, I have to say that the sound my apple laptop makes when it boots (which doesn't happen often; there is no wake-from-sleep sound) is oddly comforting.

I am actually disappointed it is being removed.

The startup sound was removed in the previous macOS version. Having a setting would be better because with buttons rather than switches and the removal of the state led it is now really not possible to know if the machine is booting or not.

The startup sound was not from macOS, it occurred earlier in the boot process that that.

This may be true, but it was removed from Apple hardware as part of the macOS Sierra update.

2015 15" MBP running Mojave, startup chime is still there.

Is looking at the monitor an option?

If it works yes, but the startup chime was akin to a PC passing post so it sounds before the screen turns on. Without the sound , if the mac does not display anything you can not really know if there is no power, or something fried or your drive is dead...

Not if it's broken. Or on a headless server. etc.

Same here, I never have any sounds enabled in Windows so I definitely would not want a chime every time I turned on a mac