The steak isn't until tonight.
What is the sensitivity of your speakers? I used the MR816x with 89 db 1w/1m speakers and could only hear noise with my ear right up to the tweeter. I've also used it with 97 db speakers at the 2011 Subwoofter GTG in Omaha. You still needed your ear about 6 inches from the tweeter to hear noise. With some JTR Noesis speakers (105 db) I could hear noise from a foot or two away. I have never heard any noise over the woofer. Any noise has always been very high in frequency.
The MR816x can be used as a standalone device once you setup routing with a computer. This means that output without the Firewire cable is indicative of any noise actually produced by the device. I've used it on 3 different computers with very low noise. I did have variations in the computers in the Firewire buffer that I had to use, but those variations were causing dropouts.
You look like you have muted everything. I can't think of anything else that needs to be muted. I repeated the mutes for the other outputs, too.
Do you have an Nvidia or ATI card? My ATI card had some real high spikes that showed up in DPC latency tester. This caused dropouts, not noise.
Do you have a Texas Instruments Firewire controller? Those are supposed to work best with the MR816x.
Here are some more tips:
Solving Problems with an MR InterfaceOptimizing Windows for DAWsI just checked the block diagram in the manual. With the UR824 I can use outputs 10-17 and bypass the mixer. With the MR816x, all DAW (or JRiver) outputs go through the mixer.
I'd also be curious if you notice a difference after running Fidelizer 3.0.
I didn't send this to you for you to have to do a lot of trouble shooting. You can just use it as a preamp for your microphone. However, it may be informative if you do find something on the computer causing the noise.