Intermittent squealing from Speakers

So I've had my Event TR-6's forever, but recently switched from unbalanced cables to balanced because of my new audio interface. Now maybe they used to squeal too and it just wasn't noticeable, but ever since the switch, the left one has an intermittent squeal (almost like the kind you used to get if you had your 2g cell phone near the speakers). It happens when there's nothing playing. I think it happens when there's stuff playing too, but I'm not sure, kinda hard to tell.
 
Everything in my setup is hooked up to one high quality surge protector/battery backup and one outlet in the wall.
 
I'm not the kind of guy that knows how to check for line interference and that stuff, so I was wondering... These balanced cables I'm using, I just had laying around... Is this the kind of thing that could be caused by crappy cables? If so I'll just go buy some new ones and see if it works, but I figured I'd ask around first.
 
Thanks!

yes sir. Focusrite Scarlett 2i4.

OK thanks for the advice. I'll definitely check into switching to good xlr cables (balanced XLR to 1/4" right? that's what my output on the interface is)... As for the USB cable I'm just using the included one. I didn't know there was really a difference in other usb cables, i thought usb was kind of all created equally when not used for charging something. I'll look into that too.

ok so make sure it specifically says balanced on both sides. cool. yea the cables i'm using now honestly were just just hand me downs so i bet that's really the source of the problem.

I remember you commenting yea. I just really wanted to go for simpler. I wouldn't have been against a separate power cable, but I really don't need so many ins and outs.... I still haven't even hooked my guitar into In #2 since getting the whole thing setup! haha. Plus I read a million reviews that all loved the thing. That being said, it's honestly something I can very much live with and overall I love my 2i4. The only time it's a problem is when my girlfriend needs to record voice overs, I need to just turn off that left monitor and then the room is nice and quiet.

yea definitely headphones while recording :-)
 
that's really interesting about the usb cable. i'll probably order one when i order my new balanced cables. might as well.

Just wanted to check in and let everyone know, the balanced XLR to 1/4" cables I bought off Sweetwater did the trick. I guess the ones I got from my friend were just old and crappy.
 
Thanks for the help everyone.