Digital noise using Mbox 2

[joey141]

Hi there.

I'm using an Mbox 2 with Pro Tools 8. When I load open up Pro Tools I get a lot of what sounds like digital noise in one monitor. It is high pitched but not like white noise. I have a recording of the noise if anyone wants a quick sample drop me your e-mail address and I'll send it to you. I'm not sure where this noise comes from exactly but here are the things I think I have eliminated:

-the speaker - works fine when Pro Tools isn't running
-the cable - connected my other monitor up using the same cable and it works fine
-the power supply - swapped with my other monitor and works fine
-the mbox output - swapped to other monitor and works fine

It's worth noting that changing the gain knob on the monitor changes the level of the noise. I am using unbalanced connectors with balanced inputs but I don't understand why it only happens when I am running Pro Tools.

The monitors are Alesis M1 Active 520s if that helps.

Joe.

[emorganproductions]

Does it happen when you open Pro Tools, or when you ope a session? ie: does it do it when PT is up but you haven't opened a session yet?

[chrisduncanaudio]

So when you are not running Pro Tools, the sound disappears completely, even with the gain boosted on the monitors all the way? Is it ever noisy when other programs are open?

When I was having this issue, I searched everywhere for this problem, finally found a Digi page suggesting that you use balanced TRS - XLR cables. If that fails, try a Monster USB cable. For me, the USB cable reduced the noise but didn't eliminate it, whereas switching to balanced cables did.