Audio Background Noise, ATI AIW9700, Detailed, Please Advise

[mbrown02]

Hello All,

I have been researching my problem in this forum for a couple weeks and found many posts discussing the issue but no real resolutions.

When the audio line from my AIW card is plugged into the sound card, a high pitched screech appears. It sounds like a cross between a modem handshake, and snowy static. The noise is faint but blatant when the speakers are up full. During quiet moments in a show, it is unmistakable and distracting. The noise varies with activity on the computer, e.g. mouse movement, application use etc. One member, cradix, described a similar phenomenon where he could even hear the ticking of the sytem clock.

So far I have tried different sound cards with no change. I tried using each input on the sound card and muting all other channels and sources but it makes no difference.

After reading about interference and copper shielding, I installed a copper heatsink on my Athlon processor and grounded it with copper wire as well, but it didn't help. Next I might try this suggestion of inserting a copper plate or screen between the AIW and the CPU. I can't be positive, but it really seems that the noise is created by the card itself. I don't have any audio noise on my system until I plug in the AIW's audio line.

ATI has been little help in terms of actually diagnosing the problem. They sent me a new AIW under warranty replacement but the result was the same. I tried the original drivers and software, as well as downloading the latest MMC and Catalyst packages, but no change.

Another post here talked about noisy traffic between AMD chips and ATI cards, and advised a new motherboard and CPU. But I've not found any corroborating information elsewhere on the net on this theory and am loathe to make such a drastic move lightly.

I moved the PCI cards as far as possible from the AGP slot but it did not help. Oh yes, I also tried using the best cables money could buy, and the result was a more glorious sounding hiss/screech/etc.

I've searched the forums here for just about every relevant term; and browsed through about 200 of the 270 headers in the capture forum. So I really am trying everything I can.

I have written to ATI to return the card and be reimbursed so that I may start over with another brand but I'm not optimistic that will go far.

Would someone out there please, please give me some more suggestions to go on. I would be extremely grateful for any guidance.

Thank you,

Matt Brown
Seattle, WA

[mastersmurfie]

What sort of sound card are you using? I had a similar problem with my very OLD ATI AIW Pro, and the only solution I found was to disable my onboard sound and invest in a new PCI sound card. Haven't had a problem with noise since. Might also try changing the recording "input" to AUX instead of "LINE IN".

Just some thoughts

[FOO]

Did you build that or buy a system ?
How is the Motherboard supported ? Lotsa nylon standoffs or
brass standoffs ?

[mbrown02]

Re the sound card, I started out with the onboard, then tried a midrange PCI card with zero change. So I could try a high end Audigy.

Re the system, I built it from all new parts. I apologize but I'm not familiar with the term standoffs, except for in action movies.

Matt

[mastersmurfie]

I believe "standoffs" are what separates the MOBO from the case-using nylon (plastic), there should be no "electrical" interference. Brass will more than likely cause a sort of "feedback"...

I have a VIA chipset, Intel P4, with AC'97 onboard sound...disabling the sound and using a Philips Acoustic Edge 5.1 sound card solved all my problems.

Not to be presumptious, but I did have this happen to me... ...I installed the new sound card, but didn't disable the onboard sound using the jumpers on the MOBO-just removed it from WXP...still had the same problems at first...

[lordsmurf]

I have this problem on one system. I merely run a Hiss Cut in SoundForge 6 (or one of my custom filters) and it goes away. It is very minimal.

It may also be in your speakers (not really there) or the hiss may be an open channel on your sound cards (again, not really in the audio file).

Shut off all but MAIN and WAVE (under Windows sound control) and listen again. Test a short clip onto CD-RW or DVD-RW and put in a set-top player.

If it is still there, it's likely your composite/coax cables picking up the power hum. I'd check the computer last.

[FOO]

Brass will more than likely cause a sort of "feedback"..

How ? Why ?

If you don't know, don't say.

I was going to suggest you make sure there is at least one brass standoff
to make a good electrical connection. Preferably more