Realtek audio, Gigabyte mobo: strange-sounding audio, mic not working

[goyta]

I have a self-assembled desktop PC - full specs in the signature below, but in short, it has an AMD Phenom II X6 1090T processor on a Gigabyte GA-970A-DS3P mainboard, which uses a Realtek Azalia ALC887 on-board sound system. I have no loudspeakers and listen to the computer sound exclusively through a Microsoft LX-1000 headset. I also have a Logitech C270 HD webcam that has its own microphone. My PC has 16 GB RAM, a SSD and a large HDD. It runs Windows 8.1 Update 1 with all Windows updates (Patch Tuesday was this week, but my problems had started before that and I'm sure they're unrelated).

Everything is working fine, except the audio, which started behaving strangely a few days ago. The problems started suddenly and I can't think of anything that could have caused them. There were no hardware changes or any intervention in the hardware, nor did I install any new software that could have messed up things.

When playing music, it sounds muffled, with the volume very low and the voice and several instruments muted, while other instruments in the background arrangement sound louder. No graphic equalizer is on, and this happens with any player software (Windows Media Player, VLC, Media Player Classic, etc.), and any source (MP3 music, audio CDs, DVDs, videos, etc.). There appears to be no hardware problem with either my headset or the onboard audio: when I run both Windows' native and Realtek's driver sound output tests, the test tune comes out loud and clear in the tested channels.

Neither microphone works to record audio either - neither the headset's, nor the webcam's, with any recording program. I have connected the headset both to the PC case's front connectors (linked to the mainboard by a cable) and to the rear ones (which are parts of the mainboard itself); no difference.

YouTube videos are also mute, both when played in Chrome or IE (using HTML5) and in Firefox (using Adobe Flash), all in their latest versions. Curiously, however, the YouTube-hosted videos from a local newspaper's Web site play the audio of their initial vignette (which appears to be synthesized or MIDI) normally, but the rest of the video with the news story is silent. I normally use "No Sounds" as my Windows sound scheme, but I've tested other sound schemes; they all work, but volume is very low, as with the music.

There is no sign of any abnormality indicated either in Windows' Control Panel or in Realtek's control center window. The driver correctly detects when the headset is disconnected or reconnected, all tests work fine (like I said, both Microsoft's and Realtek's speaker tests come out loud and clear through my headset). I have uninstalled and reinstalled the Realtek drivers several times (both the version supplied by Gigabyte with the mainboard - which in spite of a different numbering system, appears to be the penultimate one from Realtek - and the latest 2.75 generic version from Realtek's Web site); no effect. I have installed a new codec pack to see if there was any trouble for applications to communicate with the driver; no effect. I have changed every possible configuration option on both Windows' and Realtek's control panels, also to no effect.

What could be happening and what could be done, short of reinstalling Windows (which of course I don't want to do)? It surely looks like a software problem, because of the passed hardware tests and the strangely perfect vignette in the newspaper site's videos. But which software where? As you can see from what I wrote above, I've tried everything I could think of.

Thank you very much for your help.

 

[fireberd]

First thing to do is disable or disconnect the Web Cam. They have been known to cause various sound problems. It may not be the problem, but eliminate it as the problem.

Stereo Mix needs to be set as the Default Recording Device.

Refresh the RealTek by going to the Device Manager, RIGHT click on the RealTek entry in the Sound section then LEFT click "Uninstall". DO NOT uninstall the drivers. Restart the PC and when Windows starts it will reinstall the sound. This usually fixes any Windows/Sound corruptions. If this does not fix it, download and reinstall the RealTek sound drivers.