(If there is already another fix for this - perhaps a driver update, please let me know. Otherwise, read on)

So when I first got my G751 (Christmas), I noticed various issues where the sound would start crackling, looked on these forums, and found multiple threads about this issue, with no actual fixes found. I also did a Google search, and found out that MULTIPLE laptops (like, a lot of them) for multiple brands (not just ASUS) have this issue. It is a Realtek driver issue. This issue will happen with all speakers, whether the laptop's build in speakers, headphones, or other external speakers.

So, what is the cause, how do you reproduce it, and, more importantly, how do you fix it?

There are actually 2 different issues. The first one is easy to fix:

Issue #1) The sound card turns off after a certain amount of time of not being in use, and turns back on and "cracks" when a sound is played.

How to reproduce: have no sound playing for like 10-30 seconds. Then play a sound. CRACK.

How to fix:

Sort of follow the instructions in this link. I say "sort of", because the link contains invalid information.

http://forum.notebookreview.com/threads/fix-for-realtek-sound-popping-and-or-high-pitched-tone-squea...

The link says:

"Enabled - enables the power management. Default is 0. Set to 1 to disable and always prevent these noises."

The default is actually 1. You want to set it to 0 to prevent these noises. Here is a screenshot of my registry, which has the noises disabled correctly:



Also note: our machines do not use "Realtek\RAVCpl64" like the link suggests, they use "Realtek\RtkNGUI64" (or at least mine does).

So with this simple registry edit, this first crackling issue is fixed (and I guess a reboot - make sure to use restart or shift+shutdown, because a regular shutdown in Windows 8 just hibernates the machine, and does not reset the CPU cycle).

----

Issue #2) Your speakers will randomly start making constant, persisting crackling, which will progressively get worse (until it gets to the point where it is crackling like every 5 seconds), and it will continue crackling until you restart or do a shift+shutdown.

Now, for troubleshooting purposes, I am first going to mention the 2 things that I did that did NOT fix the issue. Why? Because I haven't bothered to re-enable these settings, so if you follow my fix (which will follow), and it DOESN'T work, then come back to this part and try doing these 2 things first. And let me know, so I can edit and fix this guide (and will know to never re-enable these settings myself).

1) Followed the instructions in this link to "disable all sound effects" http://corey.degrandchamp.com/2010/11/25/fixed-windows-7-sound-popping-cracking-skipping/

2) In the same Windows "playback devices" menu, I disabled all the speakers I wasn't using, as well as all the "recording devices" (since I don't use them). So my "LG TV", "Realtek Digital Output", "Microphone", and "Stereo Mix" are ALL disabled, leaving only "Speakers" enabled (I use headphones plugged into the audio slot on the laptop).

Okay, so what DID work? What was the cause of the entire issue?

This took me WEEKS to figure out folks. WEEKS. Up until then, I was literally just restarting my machine every 4-6 hours when the crackling would start, to get rid of it.

The cause? *Drumroll*

"GPU Tweak"

Yeah. That thing that tells you which video card optimus is using (intel or geforce), how much your geforce is being overclocked when in use, your fan speeds, etc? That is what causes the issue. If you just let it run in the tray like normal, nothing happens, it does its job, it switches video cards and overclocks like normal, and there are no sound issues. If you have obsessive compulsive disorder, and need to click it to make sure optimus is switching to your geforce video card properly, then BAM, the sound issues will start.

How to reproduce:

Step 1) Right-click this thing in the image below (circled in red), and click "open"



Step 2) The following screen will pop up



CONGRATULATIONS! You will now have sound issues until you reboot your machine.

How to fix (prevent) this issue:

Step 1) Never EVER EVER EVER click the thing in the image below:



CONGRATULATIONS! Your laptop will run perfectly fine, with no sound issues, no popping, no crackling. GPU Tweak will run in the background like it always does. You do not need to click it and check up on it. It works. Your games will run fine.

Another thing to note: I do not use the "ASUS Gaming Center". (image below)



I DO NOT know if this also triggers the sound crackling issue, as I do not use it, and therefore have not tested it. It has a similar big red ASUS window like GPU tweak does. It even contains a thing that tells you if GPU Tweak is on or off, so it MAY be connected to it. When you are troubleshooting this issue, do NOT open the gaming center. When you have fixed the issue, and are sure it is fixed, feel free to open the gaming center and see if it causes the issue as well. If it does, let me know in this thread so I can properly update this guide, and then NEVER use the gaming center in the future.

You're welcome.

Feel free to spread the word. I'm probably not going to bother looking up those countless other threads and posting this guide in them. At least not for a little while.

Also note: this is not related to the "subwoofer issue" I saw posted on the front page of the forums. Like I said, I use headphones. I have therefore never run into a "subwoofer issue".

Uptime: almost 4 days without rebooting, no sound issues 😄



.........brb restarting my computer, because I just opened GPU Tweak to take those screenshots. LOL


Edit by cl-Albert 3/20/15: Since this thread is getting a bit long, thought we should close it and reply at the new thread below. Thanks.
https://rog.asus.com/forum/showthread.php?59248-G751-Sound-Crackling-Thread-(The-one-thread-to-rule-...