INTERACT FORUM

Mojave is half way through his steak with his wife in Omaha.  It might be a while.

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 Interface
Optimizing Windows for DAWs

I 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.

I don't know the exact sensitivity of my speakers, but I know it's pretty high (around 98 dB).

I'm normally about 12 feet from the main speakers but if I sit at my desk, I'm right next to one of them.

The noise is easily audible anywhere in the room.  As a comparison, my internal X-Fi has a noise that's only audible within one foot of the tweeter.  I've tried a lot of soundcards in the machine, but none have had this much line noise.

And remember the noise is there even if the device isn't playing.  I'm guessing it's just noise on the firewire line and the device doesn't isolate it well.  I'm using the integrated firewire adapter on the motherboard.  The machine is an overclocked i7 2600k with nVidia 680 GTX.

The noise is a little surprising, because one of the arguments for an external DAC is that you can get away from this type of thing.

I wonder if it's worth getting a PCI or PCIe Firewire card?

Does the USB version (UR824) isolate the system noise better?

I wonder if this is a problem with all firewire interfaces like the AudioFire, etc.?

IIRC Matt, you use internal volume right? I think it's good practice to do most of the attenuation at the amp, and allow the interface to play near full scale (giving yourself a bit of headroom) to maximize the use of the bit-depth and snr. Here's an excellent article on gain staging: http://www.diyaudio.com/forums/diyaudio-com-articles/186018-what-gain-structure.html

I use a power amp with no volume.

This means an interface with low line noise is critical, since it is the preamp.

I'm currently using an X-Fi, which has virtually no noise.  The same was true of the exaSound e18, HT Omega, and Asus cards I've tested.  Some older studio cards and other cheaper cards do have too much noise.  Pops when you power cycle is another possible problem, but luckily it only occurs with some hardware.

I tried a second PCI firewire card (NEC).  The amount of line noise is comparable to the VIA card.

The noise is acceptable, but more than I would like since its audible from the seating position.

It's not as loud as the fan in my projector that's right above my head, so I suppose I should just ignore it.  Or maybe I should take the fan out of my projector...

Was it ever established whether or not the usb version is quieter than the firewire version?

-Jim

I've never played with the firewire version, but I do have the USB version (UR824) and some very sensitive speakers (113dB 1W/1 Meter), and I can confirm that it's quiet enough to use with them.  I did some testing with speakers of different sensitivities and an amplifier that is completely quiet at idle.  The UR824 when paired with the 113 sensitivity speakers produces a soft hiss audible from a few feet away.  Using it with 96 dB sensitivity speakers the hiss is only audible if you place your ear right next to the speaker.  With a pair of 89 dB sensitivity speakers it's completely inaudible to me.    

It makes sense that the UR824 would be quieter than the 816 just looking at the rated specs; the UR824 has a significantly lower noise rating and a wider dynamic range.  Over here, mojave also indicated that the USB version was much quieter: http://yabb.jriver.com/interact/index.php?topic=77508.msg525896#msg525896

Perfect.  Thank you, sir!

-Jim