Is This An Interface Problem? Solution Sound Good?

[Scrench]

My Dear Colleagues,

We, as imperfect human beings, have the capacity for talking ourselves into believing anything, even when a little voice from our subconcious is whispering "Don't Do It."

Years ago I used Cubase with a rack-mounted M-Audio interface and got professional quality sound.

My latest song is recorded using Reaper with a Zoom R8 as an interface at 24 bit/96k on a PC with Windows 7, built for gaming with plenty of memory, speed, and a huge GUI.

Everything was fine until I started mixing down.

I kind of suspected (read the first sentence again) that using a Zoom R8 as an audio interface might not produce pro-quality sound, even though it does sound okay while tracking, and is great for getting out of bed at 3 a.m. to quickly record song ideas before I go back to bed and forget them. But now I suspect I've found its fatal flaw. As I said, it works and sounds fine for recording individual elements, and okay for playing back a drum kit as a FX plug-in on a midi track, a bass track, and a rhythm guitar track. But no more than that. When I add more tracks, the sound quality gets cumulatively worse with distortion creeping in, and by the time I've added all the instruments to the mix (16 in this case) it becomes horribly distorted, almost unlistenable, even at very low monitoring levels. I don't know what else to blame it on besides the R8.

I'm using pro-quality active JBL studio monitors and have owned a commercial studio before, so everything is connected as it should be, and all levels are where they should be as well as allowing headroom for the whole mix. But this is happening at levels far below 0db, not even close to pushing the volume. The only piece of gear in my chain (Reaper on PC>R8 via USB>monitors) that I consider the weak link is the R8.

I've tested running a CD player straight into the monitors and it sounds great, but then tried the CD player through the R8, and it too, has distortion. To alleviate the problem, at least the DAC conversion, I just ordered a Motu M4 after comparing it to everything else in that price range. I'm hoping it will clean up all the garbage I am hearing.

Has anyone else had a similar experience, and does my conclusion/solution sound right, or have I overlooked something?

Thank You!

[Scrench]

In case anyone was wondering how this turned out, here goes.

After getting the Motu 4 all situated, then conducting listening tests, I do indeed hear a difference between it and the R8. It's nowhere near as huge a difference as I was hoping for, but it's there. The Motu is a little more defined, clearer, that allows me to hear deeper into the mix, and I think it has less distortion. But that was listening to things recorded through the R8. Very soon I'm going to cut some new guitar parts using the Motu as the recording interface, and see if there is more of a difference. I'll let you know.