Audio for Realtek High Definition Speaker suddenly loud and distorted

I have the following problem since yesterday evening on my Windows 7 and can't find a solution.
The audio signal for the standard Windows Realtek High Definition Speaker output is loud and distorted (if I don't set it to a really low value). I noticed the distortion when I started watching a youtube video and I was just listening to music not even an hour earlier just fine. I didn't install any program or application during that time nor did I download anything.

This is the case for the headphone jack at the front and the back of my computer.
All applications (System Sound, Music, Firefox, Games, etc.) are affected. If I switch the audio output to my TV (connected via HDMI) or my Scarlett Audio interface (connected via USB) the sound is fine.

I've tried the following things to no avail (not in this particular order):

• updating Realtek driver
• using different headphones
• making sure that no effects like EQs are enabled neither in the windows sound setting nor in the Realtek HD Audio-Manager
• virus and malware scan (ESET NOD32 / malwarebytes)
• running ccleaner (to clean registry etc. )
• closing all running programs
• uninstalling Realtek driver and letting windows automatically install one
• installing older version of Realtek driver (and later updating again, I'm at the latest version at the moment)
• updating BIOS
• updating Nvidia GeForce driver
• uninstalling video and audio codecs
• testing different bitrates and samplerates in the windows speaker settings
• disableing all other audio devices in the device manager
• unplugged the computer and used a different power source (with a different monitor/mouse/keyboard)
• a really simple hardware check (looking if everything is still connected and if there is no obvious damage)

Here is an example of what it sounds like. https://clyp.it/5bdwyiya (I reduced the volume of the sample so that it's listenable, otherwise it would be really loud)

computer specs: see my profile


I'm thinking about getting Windows 7 on a USB flashdrive installed to test if the problem still occurs if I boot from that. I'm thankful for any ideas/tips to solve the problem or to narrow it down.

- Ind3x

With all that you have done, it would appear to be a hardware problem in the Realtek sound chip on the motherboard. If the motherboard is still in warranty, contact ASUS for warranty support.

The HDMI audio uses an audio chip in the Video card, and your recording interface unit (Focusrite Scarlett) has its own audio chips.

The only remote possibility is some type of conflict between the Scarlett and the Realtek. Have you disconnected the Scarlett, rebooted the PC to see if anything changes?

(I use a Roland Octa-Capture for my recording studio)

That clip sounds like there is echo in it. It isn't a very good audio clip for a sample. I looked at it on Goldwave (audio editor) and couldn't distinguish any distortion. I'm sure its there but the clip doesn't help me.

One thing I notice is the Wi-Fi model motherboard card. Wi-Fi has been known to cause audio problems. If you are using Wi-Fi or just have it enabled, disable Wi-Fi and see if you still have the problem.

As you need the PC for production, it may be just as well to buy a separate PCIe sound card and use that instead of the Realtek. Or buy an inexpensive sound card just for testing to determine if it is the Realtek. Either of these two options would be my choices at this point.