Hi,

REW is a Digital Room Tuning software in Java that helps you figure out where you have problems with your room, such as modal problems, so you can correct them (either digitally or manually).  It's a pretty nice little software package for free.  I recently downloaded it to check my room, which I just spent a lot of time and money treating, with bass traps, sound foam, etc.  Before you can use the software, you are required to provide calibration info for your mic (if you have it) or your SPL (whichever you use) and then the software has you evaluate/calibrate your sound card, so the software can compensate for those when it takes its readings.  I own a fairly new RME HDSP 9632, with the XLR breakout cable as well as a lower priced M-Audio Fast Track Pro USB Sound Card (which I use if I ever need to use M-powered Pro Tools).  I love the RME, but I had a disturbing experience with this software REW, I just described and I wonder if anyone has any advice they might have to help me figure out if I'm doing something wrong or if I have a defective RME card. 

To take the card measurements, you simply plug your right channel out directly into your right channel in on your sound card.  Then you set your levels and the software takes a reading.  The sound card should be as close to flat as you should expect.  I tried it with the RME and I got anything but a flat response, so I tried the software with the M-Audio and instantly got a pefectly flat response. 

RME's TotalMix and DSP are a bit complicated so, I'm wondering if maybe I have something set wrong and that is why I'm getting the response I'm getting.  Instead of a simple, flat graph readout from my RME, like the one I get from my M-Audio Fast Track Pro (and the kind of readout the software's help tells you you should get from your sound card), I got a graph that I'll try to describe and maybe someone has some suggestions about what settings I should try changing in TotalMix or DSP. 

First of all, "Direct Monitoring" is turned off as recommended by the REW software to avoid feedback loop.  But nevertheless, the graph instead of being flat looks like the following:  It starts out at 0 db at 3Hz then curves up to about 5db until it hits about 100Hz and then curves back down to 0db at 200Hz, which would be fine if that's where the problem ended, but that's where it starts.  From about 200Hz all the way to 20,000Khz, the graph, instead of being flat, goes back and forth in a sine wave pattern between 0 and 5 dbs that get closer and closer together so that by the time the graph reaches 20,000Khz, the waves are on top of each other.  In other words at 200 Hz the graph moves up fairly quickly to 5 dbs and then back down to 0 and this pattern repeats itself up to 20,000Khz but, as I said, gets closer and closer together, so I guess you could say even the first long curve is just the first of the same pattern of fluctuating between 0db and 5db.  On the other hand, the M-Audio just showed a flat line at 0 db, with all other settings in the REW (Room EQ Wizard) software being the same.  The test was done at 41,000 setting and there was no feedback loop or anything because the software tells you when the sound card signal is too soft, too loud, clipping, or feeding back.  So that's the reading I got, and it made me very depressed that my RME high quality card was outshined by the low end M-Audio $150 Fast Track Pro.  I wrote to RME to ask if they had any idea what might be wrong and they just asked me to send a picture of the graph even though I did send them the actual .cal readings file.  They didn't venture a guess as to what possible settings I might have wrong in TotalMix or DSP and even implied that my card might be bad.  The card seems to record okay, but this stressed me out.

Does anyone have any thoughts or suggestions about what might cause the card to take a signal from the output and receive it back into it's own input and fluctuate by 5 dbs across the audio spectrum when the signal is a flat signal across the frequency spectrum and should give a flat reading when executed and measured by the software that generates the signal?

Any thoughts, suggestions, ideas, or experience with the REW software would be most appreciated.  I'm going crazy and don't want to spend the money on sending my card in for service, when I think it is okay.  My guess is there is something set wrong in TotalMix or the DSP but, I don't know the functionality of either program that well.  Does anyone know what could account for the kind of behavior I described.  M-Audio's Control Panel is very basic and, in turn, I got a perfect reading; that's why I think TotalMix or the DSP settings are the culprit.

Anyone have any thoughts?  Please help if you can!!!!!!!

Thanks,

marsx