Audio Background Noise Problems Anybody?, Noisy audio on my Emac G4 700 mhz Options

[abaco]

Emac Audio Problem

My brandnew Emac 700mhz has a good amount background noise in its audio output making it unusable for professional recording applications like Cubase.

The high pitched sound changes loudness and frequency depending on the position of the mouse on the screen so it seems that maybe there's some stray voltage coming in from another sub system (graphics perhaps?)

I went and bought a professional USB audio adapter from Edirol ($250) hoping that may fix the problem. It brought the noise level down at least by 3 times but the same ever changing noise is still there in the background. It seems to also transmit itself somehow through my MIDI devices as well and then show back up on the MIDI device's audio output.

It looks like a design flaw to me. Maybe some components that should have been shielded better on the motherboard. I need help. This computer turns out to be unusable for any kind of music recording. My old iMac has none of these problems and is totally noise free even with just the built in 1/8" audio output.

Any advice how to fix this? I don't want to have to buy another computer.

Thanks,
Alan Steward
abaco@go2mypage.com

[kaboombahchuck]

Another thing to consider....
Make sure your devices are properly grounded. If you are using a power strip or surge protector with the ground connector broken off, you are going to have problems. Check the ground connection outside of your house. Coming off of your power box (outside where the meter is) there should be a copper wire that is nailed into the ground (literally). Make sure it goes into the ground quite a ways. If not, pound a longer (copper) rod into the ground and connect the grounding wire to that. The best rought is to ground all your sound devices and computer to a dedicated ground. This may sound silly, but most hiss and other sound anomallies are from poor grounding.