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I am having a problem with some hiss coming through my new JBL LSR 2325P 5" Bi-Amplified Powered Studio Monitor's.

They are connected to my MBOX Mini via "Audio Cables" I purchased at Radio Shack which is then connected via USB to my iMac.

With the Mbox off the monitors have a slight quiet hiss that I think is normal for all monitors - as soon as you turn the MBox on hiss jumps up.

I dont think my monitors are damaged as they are brand new, it seems the mbox is causing the hiss, but I am not sure - could it be the "Audio Cables" or other cords/power cords running behind each other?

Instead of using the radio shack 1/4" male to male Audio Cables would 1/4" Male to Male TRS cables or XLR Male to 1/4" male cables work better and get rid of this hiss?



Any help, thoughts or suggestions would be great thanks for your time.

Sadly, it's going to be a bit trial & error to diagnose this. Ideally you're best off taking apart the whole setup, giving the connectors a clean, then reconnecting with everything down at zero and working your way along the signal chain swapping the cables etc in and out as you go.

wub wrote:Sadly, it's going to be a bit trial & error to diagnose this. Ideally you're best off taking apart the whole setup, giving the connectors a clean, then reconnecting with everything down at zero and working your way along the signal chain swapping the cables etc in and out as you go.

thanks for your input - I'm thinking it's my cheap audio cables but I can try what you said...anyone else have any thoughts?

I ended up having to use a ground loop interrupter, but that was after I did what wub suggested ;p I picked one up at Radio Shack for like fifteen bones. Cleared the issue right up.

fragments wrote:I ended up having to use a ground loop interrupter, but that was after I did what wub suggested ;p I picked one up at Radio Shack for like fifteen bones. Cleared the issue right up.

thanks I'll look into it - now is it a ground loop interrupter or ground loop isolator and how exactly does it work?

Connecticut P wrote:

fragments wrote:I ended up having to use a ground loop interrupter, but that was after I did what wub suggested ;p I picked one up at Radio Shack for like fifteen bones. Cleared the issue right up.

thanks I'll look into it - now is it a ground loop interrupter or ground loop isolator and how exactly does it work?

Good call. It is an isolator. I knew when I went to buy it. It was something to do with what you have plugged into the wall and/our power strip. I honestly can't recall the science of it. I think a power conditioner may be a preferable option in some if not all cases now that I'm thinking back. Can't tell you why. Believe SoundonSound was a lot of help on this one. But I think conditioners, good ones, start at 200 US (?)...had researched them a tad.

fragments wrote:

Connecticut P wrote:

fragments wrote:I ended up having to use a ground loop interrupter, but that was after I did what wub suggested ;p I picked one up at Radio Shack for like fifteen bones. Cleared the issue right up.

thanks I'll look into it - now is it a ground loop interrupter or ground loop isolator and how exactly does it work?

Good call. It is an isolator. I knew when I went to buy it. It was something to do with what you have plugged into the wall and/our power strip. I honestly can't recall the science of it. I think a power conditioner may be a preferable option in some if not all cases now that I'm thinking back. Can't tell you why. Believe SoundonSound was a lot of help on this one. But I think conditioners, good ones, start at 200 US (?)...had researched them a tad.

I had bad noise a while back.. Thought the speaker was damaged.. switched outlets and it went away great!
Try taking your speakers/sound card to a different room, or just simply a different outlet

my monitor hiss went away when i switched to a sound card that has balanced outputs. not sure if you mbox has those.

UPDATE: so I had a feeling it was the cheap audio cables I had purchased from RADIO SHACK and I think I fixed it by going over to Guitar Center and buying a TRS Balanced Shielded cable - this helped a lot. Thanks for all of your help guys.

Connecticut P wrote:UPDATE: so I had a feeling it was the cheap audio cables I had purchased from RADIO SHACK and I think I fixed it by going over to Guitar Center and buying a TRS Balanced Shielded cable - this helped a lot. Thanks for all of your help guys.

Good to hear you sorted it out. Personally I hate Radio Shack, but unfortunately they are the closet audio store to my house. Last time I was their dude didn't know what RCA cables were. WTF man...you work at RADIO SHACK...ain't you supposed to be knowing that kinda shit?

fragments wrote:

Connecticut P wrote:UPDATE: so I had a feeling it was the cheap audio cables I had purchased from RADIO SHACK and I think I fixed it by going over to Guitar Center and buying a TRS Balanced Shielded cable - this helped a lot. Thanks for all of your help guys.

Good to hear you sorted it out. Personally I hate Radio Shack, but unfortunately they are the closet audio store to my house. Last time I was their dude didn't know what RCA cables were. WTF man...you work at RADIO SHACK...ain't you supposed to be knowing that kinda shit?

that's pretty bad to not know what a RCA cable is and work at radio shack lol - but yeah im back in business!

yeah the bit of hiss i had went as soon as i started using balanced cables to connect up from my interface.