Intel iMac Soundcard problem

[stealthgear]

I'm trying to calibrate my iMac's internal stereo in / out, but I'm not sure whats happening.

After going through the steps I get this message:

"Impulse Peak is not where it should be, measurement may have been corrupted
-check the impulse response and captured data plots"

My setup:
In system preferences I have my output sliders set to about 50% and about 50% on my input. (when matching the levels in the calibration steps 100% output & input all the way down is too hot). I am using stereo RCA cable with adaptors to the Input/output of the imac.

This is the graph I consistently get. I am not sure if I am doing it wrong, if I have feedback, settings not right, or if its my hardware?



I just bought an ECM8000, and I wanna use it soon, so any ideas as to whats going on would help. And I dont really want to buy a soundcard if I don't need to. I used to have an expensive one, but I sold it, because results I got with my iMac inputs were OK...I haven't noticed anything wrong with my ears at least.

[fsrenduro]

I'm quoting a post from an earlier thread that might be of help to you.

fsrenduro wrote:

I found this little work around posted by Bing:

1. I set it to 44.1k, left channel.....and hit "measure" to start soundcard calibration.
2. Hit 'next' 2 times to start the 1kHz tone started.

3. I increase Record Buffer to 64k with one click. The VU meters turn a darker shade of gray.
4. I turn it back down to 32k
5. I hit cancel in the lower right corner
6. then I start "measure" again.
6a. I switched it back to right channel before doing the final calibration.
6b. hit "next" 2 time to get it going again.

6a is a step I added in between 6 & 6b (which were all one step in the original post). I found that if I didn't switch back to right channel before hitting 'next' 2 times that it wouldn't work.

[stealthgear]

That did align the graph properly, but the shape of the graph is the same, along with the major dropoff at 4k. I recorded my guitar with the ECM8000 today, and I got full spectrum on the iMac input. I also tried Signalscope pro RTA with a sweep output wired to input and it looked normal.

Any other ideas?

Update:
I tried Fuzzmeasure demo and it came out 100% normal. Maybe I should just stay away from REW on mac...

I'm okay for now with Fuzzmeaure but I wonder if anyone else has come across this issue.