I just recently built a new PC with Windows 10 Pro, i7-7700k processor and asus z270f motherboard.  I'm using a PreSonus Firestudio Project audio interface.
 
Here's my problem I'm having.
 
When I'm not running Cakewalk SONAR Platinum, everything is fine.  When I boot up Sonar, everything is still fine.  When I activate the audio engine by playing a project, a consistent, low-level but definitely audible hiss starts playing through the speakers, even when I stop the song.  Turning the audio engine off makes it go away.  I've tried different projects and they all do the same thing.
 
Any ideas on what I can do to fix this?  

Are you using Firewire? I've read a lot about needing a Texas Instrument firewire card or you will have issues. If USB is also an option try that. If you were using USB try different ports. 
Your problem is not Sonars fault but your system or drivers. 

The Firestudio I'm using is Firewire only.  I am using a TI Chipset firewire card that worked fine in Windows 7 on my old machine, but is now causing the problems on this new machine running windows 10.
 
I'm pretty sure you're right that it's a system issue and not a Cakewalk issue, just looking for help wherever I can!

Are you running any Waves plugins with the "analog" button enabled. Those things generate lots of noise that will continue even after you have stopped the song. -Mark.

Mark makes a good point I would check to see if the the noise is coming from any plugins in the project. 

karhide
Mark makes a good point I would check to see if the the noise is coming from any plugins in the project. 

As a quick test, just hit 'e' to bypass all Fx

Thanks for the replies everyone!
 
I've tried the recommendations.  The only Waves plugin I was using was the Vocal Rider, but I went ahead and bypassed all plugins to be sure.
 
The hum/hiss is still there.
 
I've also tried increasing the buffer sample rate to a higher number to see if that helped, which it did not.
 
I recorded an example of the noise turning the audio engine on and off, on a new trackless project, with no plugins on any tracks.  Here is the result I'm getting: https://drive.google.com/file/d/0B-BwaQhCiDooNW0xWVV6N0VVMG8/view?usp=sharing
 
Any other ideas?

Does that interface have front-end mixing software on it? Opening that to both instantiate it and check the internal routing may show something.

I could be an idiot.
 
I tried the boneheaded thing and turned down the volume on the speaker itself.  I guess my speakers were too hot and the noise was coming from that. Maybe windows 10 sends a higher signal than windows 7? I didn't change anything from moving from one system to the next on the speakers, so odd that turned out to be that.
 
Anyways, thanks for everyone's help!  Truly appreciated.

I have had the same problem and fixed it like this I hope it works for you:
It sounds like a ground loop by your speakers or the other gears. mine was the speakers.
Try to unplug unnecessary devices and even your speakers. I repeat again UNPLUG from OUTLET not switching off 
then plug a headphone into your audio interface and see if you still hear the noise?
If it is gone now plug in your unplugged devices one by one and see which one cause the noise. As I said mine was the speakers and I had to eliminate the ground pin to get rid of the noise.
Give me an update if it worked for you.
By the way how many set of speakers do you have?