[apollo11]

MBPro connected via a DVI-DVI cable fitted with a DVI to HDMI adaptor to Sony Bravia HDMI input.

Mini jack to mini jack conncetion between MBPro and Sony theatre system.

A lot of clock noise results.

Tone of noise is affected by trackpad use.

Disconnection of DVI cable leads to noiseless sound output.

Separating the sound and video cables by several feet does not to make any difference.

Retaining screws on the DVI cable are used in the hope that they might earth the video cable-no improvement.

Any ideas?

Thank you all for your considered response.

[ibook_steve]

Strangely enough, I've had this exact same problem with my 2.33 GHz MBP! I have a digital projector that I would connect my computer to through DVI and there would be strange tones that went through the sound system whenever I was connected. I gave up on trying to fix it and just went with an optical connection to the stereo instead of analog. Optical doesn't cause any interference and the sound is now perfect.

Steve

[apollo11]

Thanks Steve, I'll look up how to switch my connection to optical

[tooki]

Sounds like a typical ground loop problem. Going optical is definitely the easiest way to get around it.

[P]

Seconded on the ground loop. The DVI cable leads ground. The computer is grounded through the outlet, and the TV is grounded at either the outlet (common for HDTVs), through the analog antenna connection (common in apartment buildings) or both (which really isn't good, as it can cause TVs to catch fire). Try connecting TV and computer to the same outlet and see if that helps.

Otherwise, optical indeed works fine.