Audiobox USB / MAC noise

flagstaffcharli · #1 12-21-2011, 01:29 PM

A few weeks (maybe months ago) I asked about an inexpensive, portable interface for the purpose of doing quick demos of my tunes. I settled on an Audiobox USB. I've been fooling around with it much of this morning:

I'm basically going -> AT2020 -> Audiobox USB -> MacBook Pro with OS X 10.7.2 & Studio One or Garageband software.

I'm getting a problem with noise similar to what you might expect from lightly bumping a condenser microphone. But the problem persists at random intervals (every couple seconds) even after I unplug the mic and turn off the phantom power. I listen through headphones attached to the Audiobox. The noise is making it onto the track when I record, but I can also hear it with the headphones on even when I'm not playing a track. It ranges from -48db on up to almost -20db at times. Much too much noise.

Somehow, I think I'm hearing the MAC working. In fact, sometimes I'll move the cursor and I swear that's exactly when I hear the bumpy noise.

It's not the microphone or preamp. I get the noise even after unplugging the mic and turning off the phantom power. I can't seem to find a power setting on the MAC that fixes the problem. I am signed off the wireless network when working and I don't have anything else up and running.

Is the USB cable a potential problem? What does one look for in a USB cable? My Audiobox did not have a USB cable in the box, and I suppose I just blew that off because we have a house full of cables. Or is it possible that my MAC doesn't have the juice to run a bus powered USB device like this?

As for the Audiobox itself, other than the noise it appears to do what I wanted it to do. The preamps (again, other than these bumpy noises) don't have a ton of gain but they are rather transparent. I'm using the AT2020 about two feet away at chest height and getting plenty of volume and balance for voice/guitar without pushing the preamps too hard. But the noise problem defeats any chance of me using these tracks on a real project.

Thanks!

mchalebk · #2 12-21-2011, 01:54 PM

If the noise is truly getting recorded, it almost has to be the Audiobox. I really can't see the USB cable making a difference; it's completely digital.

flagstaffcharli · #3 12-21-2011, 02:22 PM

Quote:

Originally Posted by mchalebk

If the noise is truly getting recorded, it almost has to be the Audiobox. I really can't see the USB cable making a difference; it's completely digital.

OK, but the same kind of noise appears to happening at both input and output. I'm not sure I understand. The audio is digital, but there isn't there also the issue of power? This is my first bus powered device.

flagstaffcharli · #4 12-21-2011, 05:26 PM

Well, a self-powered USB hub has solved this problem for now. It's kind of frustrating though considering the advantage of a bus powered USB device is the simplicity of just plugging in with a USB cable. I assume this is a power issue. I'm not sure what happened, but for anyone else who runs into a problem like this here's a potential solution.

Anyway, I was able to record a clean track & can now get down to business.