The Unsolvable Buzzing Microphone Mystery


Oct 27, 2012
Well, hopefully not unsolvable, but damn if I can figure it out!

The players:
New stuff -
Asus Xonar DG soundcard
Audio Technica A700x headphones
Zalman clip-on mic
Antlion Modmic 3.0

Desktop PC (existing) -
Windows 8 64bit
2 x EVGA GTX 560 ti video cards in SLI
Gigabyte z68a-d3h-b3 mobo
Thermaltake Xaser III case (pretty old at this point)
Corsair 750W power supply
Wired Logitech mouse and mechanical keyboard

Laptop (existing) -
Asus gaming laptop. Don’t need many details here.

The story:
It was time to upgrade from my $20 Sony headphones and $10 logitech usb microphone to a proper setup. After testing a Plantronics 780 USB headset, I decided I wanted to stay away from USB headsets and purchase a soundcard, headphones, and a mic separately. After reading numerous reviews, I went with the “new stuff” listed above.

I hooked up my front panel audio header to the Xonar and tested my headphones on both front and back ports. Everything sounded great, 7.1 Dolby Headphones was working, and gaming was spectacular. Then came microphone time. I started with the Zalman clip-on mic, but it was extremely quiet – even with the volume and boost maxxed.

I figured the mic was just low quality, so I tried an Antlion 3.0. While the mic itself was much louder, it has an incessant high-pitched buzzing which gets louder as the mic is turned up. It is basically unusable with the buzzing. I have tried everything I can think of to eliminate the buzzing. Below I will list everything I have tried along with the results. I’m hoping someone can suggest something I haven’t tried yet.

Troubleshooting Steps:
- I plugged the Modmic into the Xonar jack, my onboard Realtek jack, and the mic jack on my laptop. The buzzing was the same across all three.
- I plugged the Zalman mic into all three jacks, and no buzzing occurred. I should note that when using the onboard Realtek, the Zalman mic was plenty loud enough and actually sounds pretty great.
- At this point, I figured the Modmic was bad. But here’s where it starts to get strange. My laptop and desktop PC are very close to each other. So I left the Modmic plugged into my laptop and turned off my Desktop PC – and the buzzing sound vanished. Even with the mic volume and boost maxxed out on the laptop, there was no buzz. Sound quality was great.
- So I’m thinking something with my PC is causing interference. I tried unplugging everything possible to no avail (video cards, dvd burner, cpu fan, all USB connections, monitor, Ethernet cable). The buzz would persist.
- I also tried plugging my PC power into a different outlet – same buzzing.
- When using the onboard Realtek, the "Noise Canceling" option actually eliminates almost all of the buzzing from the Modmic. It does lower the mic volume a bit, but its still usable. But I don't feel this is a proper solution. The root cause still remains.
- What I haven’t tried yet (because now I’m at work)
o Unplugging the Xonar card
o Unhooking the front panel audio connections (which are hooked up to the Xonar)
o Unplugging front LED lights of the case.
o Unplugging extra hard drives.
o I can’t eliminate the PSU unfortunately

So I’ve pretty much hit a wall and am looking for suggestions. What could be causing this interference from my Desktop PC? Am I even sniffing up the right tree?


That would be electro magnetic radiation from your PC ,commonly caused by coils on graphics cards or in the PSU.
It is unusual for this to propagate outside the case.
Is your case predominately plastic or have you plugged it into an outlet with no ground connection.


Oct 27, 2012

Hi Makkem -

My case is mostly aluminum ( The outlet is grounded, and I have tried plugging the PC into another grounded outlet with the same results.


Oct 27, 2012

After some serious troubleshooting, I was able to discover the culprit. I'm posting this in the hopes it will help another poor soul one day.

My Thermaltake Xaser III case has a front LED display. The "Thermaltake" lettering lights up in blue when powered on. Well, there is a little black box attached to the case which has three cables running out of it: 1) Power cable for PSU input, 2) A tiny output cable that powers the LED, and 3) An extra identical power cable that wasn't hooked up (probably for a second LED display).

I don't know if the little black box is the cause, or the two output cables, but as soon as I unhooked the Power cable to this box, the high-pitched buzzing went away 100%. Completely. No sign of it whatsoever. Something in that setup is not properly shielded I think.

I have attached some pictures for clarity. Thank you, makkem, for your assistance. And I hope this will help others in the future.

Pic 1
Pic 2
Pic 3