Running Windows 8 Pro x64. I've tried every driver under the sun (run in compatibility mode) for my army of Dell Optiplex 745's that are going to a fresh image of Windows 8. Here are the results:
Windows 8 automatically installed driver "High Definition Audio Device":
Externally connected speaker works fine. Internal speaker is not recognized at all and, if no external speaker is connected, the speaker-with-red-x icon displays in the system tray. Clicking that icon will open the a troubleshooter window.
Windows Vista or Windows 7 drivers from Dell
"SoundMAX Integrated Digital HD Audio Driver":
Drivers install successfully in compatibility mode. Externally connected speaker works fine. Internal speaker is just barely audible at 100%. Here's the kicker though: going into Playback devices->Speakers properties->Advanced and clicking the Test button produces loud, crisp test audio! WTF???
If the test audio works fine through the internal speaker, there's got to be some simple tweak or mod to fix this problem. Calling someone smarter than me...HELP!!
More about :solve dell optiplex 745 low volume internal speaker
I can't look in a W8 Control panel at the moment because my laptop with it installed is out on loan at the moment but is there a tick in Control Panel>Sound to "only use default device"? If so, all apps will go to the externals if they're set as default. Is there a specific app you want to use the internal?