I'm assuming you want to change the actual WAV file that is used as the start up sound. If not, ignore this post.
The link that
@Grizzly posted is on the same track as what I describe here, but the filename has changed, and you don't need to set the ExcludefromCPL to 0 as Windows ignores whatever you select as the start up sound there. The following is an update to that process.
I've managed to get the startup sound playing on my Windows 11 test PC with ALC4080 USB Audio.
You can play around with the sound CPL all you want, it won't work.
There are two ways of achieving the same result. For me, I never do inplace upgrades and between fresh installs I don't update programs or Windows. Like to keep my systems stable. But a fresh install is done whenever Microsoft manages to release a pacth that doesn't break things (Which is getting rarer by the day).
The startup sound appears to be embeded in the c:\windows\systemresources\imageres.dll.mun file, under the wave category at 5080:1033.
You should download the program resource hacker. A portable program.
Copy the c:\windows\systemresources\imageres.dll.mun file to a temporary location.
Run resource hacker and open the .mun file you just copied.
Expand the wave category.
You should see an entry 5080, select it
You can click play if you want to hear the default windows startup sound.
Right click on 5080 and select replace.
Navigate to the Windows start up .WAV file you want to use
Click replace.
Now save the imageres.dll.mun file.
It will create a backup with "original" in the file name.
Now this is where the two paths diverge.
Being a tinkerer I build my own windows images, integrating and removing things to get Windows how I want it.
All I need to do is copy the imageres.dll.mun file to the folder where my offline image is mounted. Recreate my install.wim, create an ISO and burn to usb drive.
But if you want to do this on a live system it's a little more difficult with the security protections M$ has put in place to stop you doing this type of stuff.
You need to grant yourself permission to the file, after taking ownership of it. Make sure you have Modify permission to the c:\windows\systemresources folder, and copy the modified imageres.dll.mun file to that folder. Reboot and you should have your new sound play at start up. If you get errors that the file is open in explorer when you attempt to copy it you may have to do this in safe mode.
Caveats: There seems to be some issues with either the ALC4080 USB Audio, the driver or Windows. On some systems Audio takes a few seconds to initialize after Windows starts, which means you'd never hear the startup sound anyway. I haven't been able to narrow down the exact cause here.
Good luck
