Mac Os X Startup Sound Download Wav
Updates 15th September 2015 - I added the Mac OS 9 startup sound thanks to Matthewscratchaaaa finding it. 27th November 2015 - The word 'Playing' now shows when a sound plays, thanks to Blahphone20 (I edited it to make it more accurate, by the way). I also made it so a stop button shows when a Mac sound plays so you can stop any Mac sounds when you want to. 28th November 2015 - You can now see how long a sound has played for when one plays. 13th December 2015 - I changed the the instructions, notes & credits a bit. Since Bip and Newbip are the same, I removed Newbip, thanks to what Blahphone20 said a while back. Also, I made the text vector to make things look better and to make it easier for you and me to edit.
Mac Startup Sound Wav
26th December 2015 - I put all the sound buttons of this project into 1 sprite while retaining full functionality thanks to cloning. Because of this, since then, it makes this Scratch project load for a little bit of time unless you use turbo mode (if you use turbo mode, the loading will be almost instant. 30th December 2015 - I fixed a bug where the sprites that show when Mac sounds are playing kept showing. 15th January 2016 - I changed the position of the word 'Playing' a bit to the right. 3rd April 2016 - I made the red circle into a square with the same color that the red circle had when it was still there. That same button also tells you what it does when you put your mouse cursor over it. 4th April 2016 (1st year anniversary of this Scratch project) - This Scratch project now has a proper loading screen (it lasts as long as it did when it had no loading screen).
24th June 2016 - You can now go into the sound mode menu, but the sound mode slider can't change sound modes at the moment (it will work someday). This Scratch project's name was reverted back to Mac OS 9 Sounds. 8th February 2017 - The sound mode menu was removed and the play buttons' graphics were improved. 25th February 2017 - The notes and credits were changed a bit. Also, the play buttons for Quack and Click are aligned more correctly with the text that labels them, the loading screen went from white text with a black background to black text with the same backdrop used after the loading process and the play buttons are more detailed. The background and sounds included in this Scratch project were made by Apple for Mac OS 9 computers.
From within Mac OS, but that doesn't count as start-up. The startup sound implementation to the OS X. 
Wav file startup sound. Where’s the Startup Boot Sound on New iMac & MacBook Pro? If you mute the audio on your Mac before a reboot. Bootcamp and Mac OS appear.
Mac Os X Startup Keyboard Shortcuts
How to Temporarily Disable the Startup Sound Your Mac’s startup sound depends on the volume level your Mac was set to when it was shut down. If your Mac was set to maximum volume level, the boot chime will be played at maximum volume. If your Mac was muted, the startup chime will be silenced. To disable the startup sound, just press the “Mute” button on your keyboard (that’s the F10 key on a MacBook) before shutting down or restarting your Mac. If you ever have to restart your Mac for some reason but you don’t want it making any noise, just do this. If you don’t have a Mute key on your keyboard, you can always just set the volume slider to the lowest level it will go. That accomplishes the same thing.