Hello, I recently began building a little home recording station and recently, every so often the monitors will have a bit of a static noise, as if I'm brickwalling but it's constant and regardless of what sounds are coming out(videos, recording, listening to any type of music, etc.). It usually happens when I would plug my external harddrive in, but tonight it just starting doing it after I recorded a little bit(although I did turn my keyboard off, some maybe that's it?).

My set up is:

-IMAC(newest ones, the flatscreens)
-Focusrite Scarlett 18|6
-2 M Audio BX5 monitors.

Additional Info in case it helps:

The Focusrite and monitors are plugged into a powerbar while the IMac is plugged into a wall outlet. The monitors are linked to the Mac via the interface, which is going through a USB 2.0 into the MAc. I also have an Ipod, an external harddrive, and my keyboard in the other USB slots. I know I said my external harddrive usually caused a hiss/static, but it's been in for about a week without any problems.

Well that's about it. Please help and thank you!
2 updates: I forgot to mention I'm using garageband(don't laugh) as my DAW.

And I changed audio back to the mac on both GB and for the MAc itself, then changed back to the monitors and the static went away. This is usually how I fix it(or it just goes away after a couple of minutes). I would just really like to stop this from happening D;

EDIT: I know this might be an actual issue, but I also notice that when the monitors are at a high volume but nothing is playing, there's a low hiss. I know this is probably just a sound made by the electricity going through them, but is there a way I can fix that as well? Is it a potential problem?
Last edited by Nirvana00125 at May 8, 2013,