(Registry hack) Disabling internal speaker on Mac Mini

[shteve]

Hi all,

I've just found a way to disable the internal speaker output on my Mac Mini with the default Boot Camp drivers installed (i.e. no re-installing Intel or Dell drivers on top of)

You need to find the section in the registry corresponding to the sound driver.
It should be under here on all computers:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Class\{4D36E96C-E325-11CE-BFC1-08002BE10318}

Then beneath that there should be a load of sequential four digit numbers; each one of these is a multimedia driver. On mine the sound device driver was entry 0005 but it may vary on others. You need the one with value Driver = sthda.sys in it.

Under that one, go to the \Settings\GPIO key.

There should be two binary values with names 00 and 01. Both will be set to value 85. Change 00 so it is set to value 05 instead. Regedit should then look like:

(Default) REG_SZ (value not set)
00 REG_BINARY 05
01 REG_BINARY 85

Finally, go to Device Manager and disable then enable the "Sigmatel High Definition Audio CODEC" driver so that it reads the new configuration in.

You should find that only the headphone/line out socket is enabled now, and sound to the internal speaker is cut.

If anyone else tries this, please let me know if it works on your system!

Steve

[mcgull]

This worked on my regular MacBook. The only difference was the entry was number 0015 instead of 0005.

Nice work, thanks!

Mike

[WhiteEagle]

does mic still work if i do that?

[shteve]

Originally Posted by mcgull

This worked on my regular MacBook. The only difference was the entry was number 0015 instead of 0005.

Glad it worked! Do you mean that you changed it from 15 to 05, or from 85 to 15?

Originally Posted by WhiteEagle

does mic still work if i do that?

Yes it should do, I successfully tested it on mine afterwards. I don't know about the SPDIF in/out though as I've nothing to test that with.

[AndyB]

Thanks for that - worked first time on my Mac Mini, think I had to reboot though. How did you figure that out ?!!

[shteve]

Originally Posted by AndyB

Thanks for that - worked first time on my Mac Mini, think I had to reboot though. How did you figure that out ?!!

It was all trial and error.. About half a hour of going through various registry settings for the driver and fiddling with the values (adding, deleting, flipping single bits) until I found what affected it.

[fernando20]

Wow! Thanks a lot dude! Worked perfectly!

[kaidomac]

Hey, let's get this hack out there! I put together a zip file containing the reg files with instructions. I posted a thread over at the Mac Forums to get some beta testers for the different models:

http://www.mac-forums.com/forums/sho...479#post226479

It'd be great if we could get this working across the entire Intel line! shteve and mcgull, I put you guys in the credit if that's okay Chime in with your data and I'll see if I can get a final version that supports all of the current Intel machines together!

[cowneko]

Yipiiiiie it works on my Macbook Pro 15"

Here the settings:
Firstly there's no 01 entry, so you only have to modify 00 from 85 to 80 and voila!!!

works like a charm.....

Thanks for the hint!

[kaidomac]

Originally Posted by cowneko

Yipiiiiie it works on my Macbook Pro 15"

Here the settings:
Firstly there's no 01 entry, so you only have to modify 00 from 85 to 80 and voila!!!

works like a charm.....

Thanks for the hint!

Settings updated in the thread above! Now supports:

-Intel Mini
-MacBook
-MacBook Pro

A few questions:
1. MacBook owners, does your registry have the 00 and 01 entry or just the 00 entry?
2. iMac owners, what settings do you require?