Hey eveyone, I'm looking for some help. 
 
I've been having some major noise (ground hum like) from my studio monitors on a new PC build. I'm able to get rid of most of the noise if I use the ground lift on my sub that feeds my monitors. 
 
However, as soon as I boot up Sonar and the audio engine loads I get this low level hum. The only way I can make it any better is by increasing the latency of my audio interface. This has me totally baffled. If I use this same interface, with the same speaker setup with a Mac running logic - it's silent.
 
I've checked my receptacles, and they are grounded. The noise only happens when my PC is on. I've tried removing internal components one at a time, but that doesn't resolve the problem. I'm using a EVGA 80+ Silver PS, maybe it's causing the noise? But why does the noise only happen when I'm in Sonar?
 
If I go to the preferences menu, as soon as it loads the noise stops. Then as soon as I go back to the main view in Sonar it comes back. 
 
Anyone ever have something like this happen to them?

What interface are you using, and how is it connected? It is very possible to get crosstalk inside the computer itself, so would help us better if we know the components in play (using same outlet, USB hubs, etc.).

I'm using a Roland Octacapture. Everything is plugged into the same UPS at the same outlet (I've tried changing outlets as well). The interface is plugged into the Motherboard directly, and I've tried multiple USB ports.

Additionally, this noise only happens in Sonar. I downloaded a trial of Cubase, and it's dead silent at the same driver settings... Maybe a rouge plug-in? 

How cramped is everything in the area of your DAW?  Sounds like you may have some cables crossing each other.  If a cable carrying electricity (ie power cord for PC, Monitor, etc) crosses over a speaker lead you can get that.
 
John B.

Best way to trouble shoot is to eliminate as much as possible and see at which point the hum returns. It might always be there and just gets louder under certain circumstances. 
 
I would defiantly remove the sub from the signal path first. 
 
Do you hear anything with headphones on? 
 
 You try different cables etc. 
Even different USB cables, make sure to use one with a ferite choke 

Noise from opening Sonar could come from a humming input assigned to a track which is echo-enabled. Another possibility (?) is some "console emulator" that deliberately generates hum. Both would disappear when opening Sonar's preferences or disabling the audio engine.

I’ll state the obvious. You’re running balanced cables, right?

stokedboss
Additionally, this noise only happens in Sonar. I downloaded a trial of Cubase, and it's dead silent at the same driver settings... Maybe a rouge plug-in? 

Since you are trying different DAWs does CbB (use the BandLab Assistant install process) have the problem? Make sure when creating your BandLab account use the same email as your Cakewalk account.

sock monkey
Best way to trouble shoot is to eliminate as much as possible and see at which point the hum returns. It might always be there and just gets louder under certain circumstances. 
 
I would defiantly remove the sub from the signal path first. 
 
Do you hear anything with headphones on? 
 
 You try different cables etc. 
Even different USB cables, make sure to use one with a ferite choke 

I had a similar a while back that drove me crazy for months. It ONLY happened in SONAR Platinum. Never in Pro Tools, ACID Pro, Vegas, or Sound Forge.
Noise in the monitors and in the head phones, however is never seemed to find it's way into recordings.
 
As strange as it may seem, it was a MIDI cable gone bad. The noise wasn't in the DAW itself or any audio I/O, it caused by the way Splat configures MIDI I/O upon launch.
 
 Just moving my outboard gear rack about one foot to the left caused the problem with a 5 pin dyn MIDI cable running from my Roland JV synth module to the MIDIMAN 8x8 USB patch bay interface caused a ground short.