The 10.6.8 "AppleHDA.kext" file is buggy; it can not decide between 2ch or 5.1ch, it picks surround for most parts. If you still have sound problems then try this;
This worked for me but don't replace the "AppleHDA.kext" extension delete it first then follow the instructions.
Happened to me too. No listing for Internal speaker after updating and upgrading. Headphones work, but only digital out was listed when not plugged.
To fix it, I tried it all... replace AppleHDA.kext, reset smc, reset pram, installed voodooHDA, retored original.... nothing worked.... and nothing I could find in anyone's issues worked, and upgrading to OSX Lion did not solve it....
Why? I just found the solution and it was a hardware problem...... (That perhaps pre 10.6.8 ignored?)
The usual reason for this problem is that a microswitch in the headphone socket has got stuck. You can confirm this by looking into the headphone socket - if you can see a red light, then the switch is stuck.
The solution is plug and unplug some headphones into the socket 20-30 times. If that doesn't work, then use a non-conducting probe to reach into the socket and gently release the switch.
I had the red light and now realize only digital out was listed because my MBP thought something was plugged into it...
If you are frustrated with no sound and already had 10.6.8 before upgrading to Lion but your sound is still not working - no joke - keep plugging your headphones in and out and just keep rebooting.
I had to reboot at least 4 times including installation and on the last reboot the white screen hung for quite a while, I thought it was freezing but it came through. This upgrade was a shocker from Apple, whoa.. Can't say it was smooth like usual with Apple, but Lion does have serious potential.
It's crazy though, I have to relearn everything and it took a while to set up the settings to where I could even maneuveur around... It's still weird but I'll keep an open mind, I know Apple will keep tweaking it.
Customizing "Gestures" is too restricted i.e., "Launchpad" is so awesome but I wish I could make another gesture for it. "Mission Control" sounds real sillly, by the way, for Apple, that is.
Thankfully this post was here to keep me motivated and not frustrated but seriously, plug it in and out a lot, keep checking your Audi/Midi setup and rebooting. It works.
Okay, I tried EVERYTHING.
I even did the downgrading to the 10.6.7 HDA.
HERE IS THE SOLUTION:
YOU WILL NOT NEED TO LOOK ANYWHERE ELSE, IF YOU FOLLOW THESE STEPS:
1. Download and install the 10.6.8 Supplemental Update from Apple (link below).
2. Once the update is installed, and the system has restarted, type "Disk Utility" into Spotlight, press enter to launch it, and select your hard drive on the left. Then click "Repair Disk Permissions." (This step may or may not be necessary, but is a good idea in case there are discrepancies from the update).
3. Once the utility is finished, plug in some headphones. Then, press the Option key and click on the speaker icon in the menu bar.
4. Click the Headphones option under the "Output Device" section. You should get sound.
Unplug the headphones and ensure that the audio is not muted. You should now also get sound through your speakers.
THIS WILL WORK. DO NOT MESS WITH VOODOO, etc. I hear that will just cause kernel panics.
If you still have problems, try resetting the PRAM by simply shutting down the computer. Hold Command+Option+P+R before the gray screen appears. Hold it until you hear the tone a second time, then release.
Tried everything and this solved my issue. Installation was flawless and sound returned even during installation.
It didn't solve my original problem, which was the absence of audio when connect my MacBook Pro with a digital optical toslink cable to my Pioneer VSX1021. Analog audio from my MacBook Pro was restored though, along with the sound through my internal speakers after the installation.
Still looking to find a solution for the digital optical audio out poblems which seem a lot of people have after upgrading to 10.6.8.
If anybody has a solution for it, please add it here. Thx!
My problem was I got sound from the internal speakers but not from the Output Audio Port for my external speakers and headphones.
After reading jonpaul's post, I downloaded installed the 10.6.8 Supplemental Update from the link http://support.apple.com/kb/DL1429. When I checked the Sound in System Preferences (Option key and click on the speaker icon in the menu bar, Sound Preferences...) I noticed the output volume at the bottom had the mute box checked.
When I updated to 10.6.8. the mute box may have been checked by default. I might have not even needed to install the Supplemental Update at all. If you had the same issue, that could be the first thing you check before installing the Update. If not, just follow his instructions; very well written out and easy to follow.