Line-In Noise

[aschlesinger]

I have an iMac G5 PowerPC running OSX 10.4.11. I occasionally use my Mac for audio recording, particularly with BIAS Deck 3.5. I recently discovered noise coming in on my line-in while getting ready to record some audio tracks. I have no audio input devices connected although I am seeing the VU meter pulse when I have the input volume set as little as a hair more than midway in Systems Preferences> Sound> Input. I have disconnected all cables besides the power cable and this still persists. I've tried switching between line-in and the internal mic (which doesn't reproduce the same problem), adjusting the audio MIDI setup and the noise persists. The pulsing on the VU meter in the sound preference isn't steady but somewhat irregular as if there were music or dialogue or some sort of signal playing in the background. Of course this seems to be causing a low level hiss in my audio recording playback (not audible while actually recording).

Any suggestions?

 

[ChrisA]

Any suggestions?

Buy a USB or Firewire audio interface. As you have discovered, the built-in interface is not noted for its audio quality.

 

[aschlesinger]

Buy a USB or Firewire audio interface. As you have discovered, the built-in interface is not noted for its audio quality.

I have a USB interface and, even when I create an aggregate device in audio/MIDI set up to accommodate this, I still get the noise reading in the audio preference VU.

 

[ChrisA]

I have a USB interface and, even when I create an aggregate device in audio/MIDI set up to accommodate this, I still get the noise reading in the audio preference VU.

You say you have removed ALL the cables from the computer? Maybe not. I bet the AC power cord is still attached. I'd suspect that connection of being the source of the noise.