Ground loop isolator converters and placement

[LeeYoo]

Why are you doing all of this.
I don't see a groundloop (if you are using TRS!! cables between your interface and speakers).
Leo..

[Cactus Thrower]

Originally Posted by LeeYoo

Why are you doing all of this.
I don't see a grounloop (if you are using TRS!! cables between your interface and speakers).
Leo..

I think I've misunderstood, I keep getting humming sounds over my monitors

[LeeYoo]

Hi,
It will take a few posts to sort this out
I assume you are using a PC, not a laptop.
And nothing else is connected, as on your drawing.

The computer/ LCD monitor etc. are grounded via the power cords.
Your audio interface is only grounded to the PC via the USB cable.
No loop, and no problem yet, because this is only "data", not "sound".

Then it travels to your monitors (which are grounded through the power cords).
When you connect the monitors to the interface, a groundloop is made.
PC powercord > PC > USB cable > Monitor cables > Monitor power cords > power multibox > PC powercord.

"Sound" only travels between the audio interface and the monitors.
Unbalanced cables here would use that (dirty) ground as an audio return path, and add hum/interference.
Balanced cables are not using that ground.

So.., are you using unbalanced TS, or balanced TRS cables.
Leo..

[Cactus Thrower]

Yes I'm using a PC and the only thing with plugs on it are the two monitors, the pc and the LCD screen.
I'm using these cables which came with the monitors which I'm guessing are unbalanced TS? I'm a super noob
Thanks for taking the time to help, I really appreciate it

[Cactus Thrower]

I've just checked online and the audio interface only has balanced 1/4 output and the KRKs have balanced XLR and 1/4 inputs on the back.
The audio interface is very close to the monitors so I'm right in thinking I should get the shortest TRS cables I can? Is there any specific type I should buy?

[LeeYoo]

Hi.
The picture shows an unbalanced plug!! Wrong here..
Your interface is according to the specsheet balanced.
http://www.alesis.com/io2
Get some TRS to TRS cables.
Length and quality is not important, because it's low impedance line level.
This will most likely fix your problem, and as a bonus increase the volume with 6db.
Leo..

[Cactus Thrower]

Thank you for the response. Would this cable be ok?
Stereo TRS 1/4" - 6.35mm Jack Lead / Patch Cable 0.5m | eBay

[LeeYoo]

Cable would be ok, but do your really want to buy 50cm lengths?
I would sugest 1-2 meters each, so you can spread the speakers if you want.
Good stereo needs a triangle. Left speaker, right speaker, your head..
2m 90deg Stereo TRS 1/4" Jack Guitar Lead Cable Red Right Angle to Straight | eBay
2m 90deg Stereo TRS 1/4" Jack Guitar Lead Cable Black Right Angle to Straight | eBay
These noobs call them "guitar leads"
Best to check the ring contact continuity with a multimeter before using them.
Leo..

[Cactus Thrower]

Thanks, it was the guitar cable labelling that confused me. A lot of the listings called the cables guitar cables too and it didn't make sense to use guitar cable on monitors to me
I've ordered those cables and I'll see if it helps.
Thanks for your help, it's greatly appreciated