Weird computer noise issue

[discofuel]

I have an iMac and Yamaha HS80M monitors.

I previously owned an M-audio FW410 interface and I would get a loud computer noise through my monitors - whirring/buzzing noise when hard disk spins or when I opened applications/finder windows.

I purchased an Apogee Duet 2 and when I connected it the noise was completely and utterly gone. I was so pleased and I assume the balanced outputs and quality of the interface fixed this.

However, I've just moved into a new house and hooked up my equipment and the noise is back as bad as it was with my old interface.

It's driving me mad! Any idea what's causing this?!

Thanks

 

[johnhw]

https://www.macrumors.com/2011/07/22/apple-recalls-some-imac-seagate-1tb-hard-drives/

Could be recalled or a hardware issue.

 

[FrankHahn]

It appears that the noise (probably due to resonance vibrations) may be due to the uneven surface which the iMac is put on and/or displaced part(s) related to the fan. Try to adjust (move a bit, tilt slightly, pat lightly, etc) the iMac a few times and see if the noise can go away. If you have gotten magic hands, you might disperse the noise.

 

[discofuel]

Plugged my monitors into another power outlet and it's all fixed!

Now silence, beautiful silence