Loop-G-Loop

As stated in a previous post, I had picked up a copy of DCS A-10C on Steam for $20.  But in order to play it at 3840x1024 resolution at respectable frame-rates, I picked up a HIS IceQ Turbo Radeon HD 6970 2GB.  This card manages this task quite well.  You can read some of the settings I had to put in place to get good framerates (as there were some compromises) here.  For all the other games I have, it's overkill. It came with Dirt3, it stays cool, and it matches other pcbs in my case (blue!).  However, it is advertised as only taking up 2 slots, but does in fact take up 3. My Gigabyte GA-P55M-UD2 motherboard is equipped with a 16x pcie slot, followed by 2 pci slots, then another pcie slot that is only 4x (but can take a full sized video card.)  Since my video card blocks the two pci slots, I had to evict my Audigy 2 Zs Platinum Pro PCI sound card. And since my second pcie slot isn't really effective for a CrossifireX setup at only 4x, I figured it would make sense to put a nice pcie soundcard in there.  So when a refurbished  X-Fi titanium pcie showed up on Newegg for $36, I snagged it despite my previous experience with Creative.

Thanks to Creative's awesome drivers (sarcasm), getting the drivers for this card to install was a pain. Even after uninstalling my old drivers, I kept getting an error saying more up to date drivers were already installed. I finally had to manually delete any and all registry keys from my old hardware (even after Driver Sweeper and CCleaner). Then I was finally able to get the driver to install. I also had an issue where my firewall software was automatically blocking the auto-update, but was able to manually allow it and get my bundled software. And for some reason, it took nearly a whole morning to download 150MB. Unacceptable.

Also, popping and crackling sounds seemed to result from changing 'modes' while audio was being played. However, it would go away after reboot. Then I realized that it states very clearly on the mode switcher in the audio control panel that it is recommended to quit ALL audio applications and games before switching modes. Obeying this rule seemed to reduce audio artifacts.

Another issue I thought I had is that there was a lot of noise from my computer coming through the speakers and when I was using headphones out of the front audio.  Additionally, with the volume all the way up on my old card there was very little noise. This one I could hear all kinds of system stuff (on speakers or headphones.) It was very annoying and sounded as bad as (if not worse than) my onboard audio.

I originally thought this was the fault of Creative, and the fact that it was a refurbished card.  I thought it was broken.  However, after some troubleshooting (I did want to make sure I knew what the problem was, and I didn't really want to pay to send my $36 card back) I realized I had a completely different problem.

I had a ground loop.

I have had experiences with ground loops before.  Most notably in my car when I've powered an audio device (like an mp3 player or DVD player) with the cigarette lighter, and then fed the audio into the car stereo.  When you do this you can hear the hum of the alternator through the speakers as a result of the ground loop.

For my computer, it was actually coming from the front audio and front USB ports sharing a common ground, resulting in being able to hear everything I plugged into the USB port. To test it I plugged in a usb hard drive into the front usb and plugged my headphones into the front audio jack: man you could hear everything that drive was doing! I was able to plug my headphones in the rear, and it sounded so much better.  To be sure, I have a ground loop isolator (that I usually use in my car) and plugged it into the front audio port and then plugged my headphones into it. Dead silent. No noise. Plugging in the USB hard drive with the ground loop isolator and my headphones plugged into the front audio still allowed me to hear quite a bit of sound from the drive, but it was attenuated.  I found out too that a lot of cases do this (search on Google for it). Even high end cases have this issue. It is not the card: it's the case. In my instance an NZXT Vulcan.

So in the following post, I'll show you what I did to fix this problem.