USB noise through DAW and monitors?

Hey all, I don't think this is a specific Sonar X2 question more than a general system question, but I wanted to see if anyone else has run into this.
 
I'm using a DELL laptop for Sonar X2 (works great, believe it or not!) and I have a Tascam US-1800 interface connected via USB.  I'm using a Furman PL8C power conditioner, m-audio BX5a monitors and SBX10 subwoofer.
 
When I plug everything in and turn it all on, I get this god awful buzzing/hum/noise (inconsistent noise, not a steady hum) coming through the monitors.  I recently added the Furman to see if I just had some dirty power, but I get the same result.  Now when I unplugged my laptop from power, the noise stops.  Clearly something is bleeding through the USB and along into everything else.  Is there anything out there that I can use for a USB filter or power filter? 
 
 

synkrotron


I get the very same thing with my laptop setup.

My "work around" to this problem, although I wouldn't suggest anyone else does it, is to remove the earth from the plug of the laptop power supply. It works.

I've done this as well... by plugging the three pronged plug into one of those 3  prong to 2 prong adapters... if worked to remove the hum when I was using a Korg synth.

it's commonly known as an earth loop.

Is everything relevant to audio plugged into the same outlet? If not, you could be plugging into separate circuits and that would make this kind of problem much worse. 

While you're at it, try moving any non audio related things like lamps to another plug/circuit.

Many laptop external power bricks don't provide very clean power and this kind of noise is a very common laptop problem.

You can't fix it up by using things such as star pattern power linking as the problem is not an earthing issue ; rather poor cheap power supply design.

PLEASE: NEVER do the remove an earth pin trick. While it removes the hum it also opens you up to the danger of electrocution if a fault should occur.

As already mentioned, there are devices you can buy to eliminate the hum or you can try replacing your laptops external power supply.

I need to make one thing clear here, it is NOT a humming noise. It is more a digital data noise. If you drag your mouse across the screen or switch windows or do anything related to the display, the sound changes slightly.

It is not an earth loop either. I know enough about this subject to know this as fact.

The dodgy power supply theory is a good one. I also had this problem on my desktop DAW and I isolated the problem being caused by one of the monitor screen power supplies. I removed the earth on that too and it solved the problem. And in this situation I was using a PCI soundcard, not USB, so that discounts it being a USB problem, in my mind.

For me it's not much of a problem because I don't often use my monitor speakers, but I should, some day, find a more suitable solution other than removing the earth connection.

At the moment I am just using my laptop monitor.

This is why this forum rocks! Thanks all for the replies and things to try,
 
synkotron is correct in the fact that the humming "changes" when I move the mouse.  It definitely stops when I unplug the power cord either from the wall or the laptop.  My workaround has been working from battery (GAH!) when I really need to listen to things. 
 
I'm leaning towards the powersupply in the laptop being somewhat ****ed, but I can't do much about that right now.  I plan on moving to a non-laptop setup at some point, hopefully that will "fix the glitch and work itself out naturally".  (guess the movie!)
 
Anyhow, I may try the HumX to see if it works, it's a cheaper method to try for now.