[Paradigm]

I recommend to a good friend of mine the Asus STX to go along with his newly purchased Beyer Dynamic DT 770 250 Pro's. He is very pleased with the sound quality and performance of the card. However it seems he is unfortunately suffering from a very well known and common problem with the STX mic input. When gaming it seems there is either EMI(from the graphics card at full load) or a some power grounding issue causing the sound card to creating a very annoying buzzing sound when ever he uses the mic to talk. This only happens when he is gaming since then his GTX 670 is being used. Googling this problem has only resulted in many complaints from people with the same issue and with asus offerring no solutions to the problem. Google has also brought to light that this exact same problem has been reported on the lower end ASUS cards as well.

Below is a audio clip demonstrating the exact symptom he is experiencing on his the STX that others are also having.http://www.youtube.com/watch?v=i0zuD0c0SRQ

I was hoping through the grace of god that maybe or possibly someone on here might be able to offer some insight into resolving this problem. I wonder is this due to a faulty card or a result of unavoidable EMI. For the record he has tried moving the sound card at the bottom of his motherboard furtherest away from the graphics card and the issue still remains.

 

[stv014]

I presume this problem occurs using the front panel microphone jack (the 1/4" jack at the rear expects a max. 2 Vrms line level signal) ? The microphone input is not really good on these cards, as it is noisy, and the front panel on many/most PCs is prone to interference and ground loops. For the best quality, you would need an external pre-amplifier and connect it to the line input, or another device/card that has a good microphone input and does not require using the front panel.

 

[Paradigm]

This is taking place directly from the back mic input.

 

[doco]

i had the same problem whenever i used my mic from the back of the stx. there would be a slight buzzing noise whenever i talked on skype or vent. i solved it by moving my gpu down to the second pci-e x16 slot on my motherboard and it fixed the problem. i guessed the stx was getting EMI from the gpu for some odd reason. is your friends gpu right above or below the stx? my gpu was sitting right below the stx VERY close before i moved it.

 

[stv014]

The rear input is actually a line-in, although it might be used with microphones that do not need any power, and are sufficiently sensitive. Did you also try the front panel microphone jack ?
The input section of the Xonar ST/STX unfortunately has no EMI shielding, both the input op amps and the CS5381 ADC are at the bottom area of the PCB that is not covered by the EMI shield.

 

[yslee]

I had the same problem too, with my previous GPU, a Geforce GTX 560 Ti. Switching to a Radeon 7950 has minimised the problem. The issue is still there, but only if I really increase the recording volume to an unusable level.

 

[KonaBear]

will be ordering the STX soon and will give it some testing time to see if I have the same problem and let you know

 

[General]

Is there still no solution to this? I currently use the stx with my Astro mixamp, and the sound is great, but the mic is just horrible.

 

[discouheguo]

both the input op amps and the CS5381 ADC are at the bottom area of the PCB that is not covered by the EMI shield.