Low mic input level + strange measure results

[vvolant]

hello

It is my first time using REW.

I Have 2 soundcard in my PC: the original realtek HD audio on the motherboard + an additionnal M-audio revolution 5.1

First I tried to calibrate the M-audio with some trouble because of the conflict between the M-audio control panel and the window XP volume control. I eventually obtained a quite good response for my card and saved it as the souncard calibration file

Then I plugged the microphone (Behringer ECM8000) to the phantom power (behringer ps400) and the phantom power output to the line input of the revo 5.1
Using the "check levels" button in the REW "Measure" page, I was not able to reach a sufficient input level, with the input line level set to the max in the revo 5.1 interface, output level also set to the max, and the level control button nearly to the max on my HT preamp. The output sound was really unbearable to my ears, I guess > 100db, however not enough when back in the soundcard (around -30db). What is the pb? Do I need a separate preamp or the microphone. Is the Behringer PS400 not enough?

Second I tried the same operations with the realtek audio card. The card rsponse is quite bad compared to the M-audio but I could build a calibration file without trouble.
Then I plugged the microphone again, this time I could reach a good input level to perform a measure (however I had to put input and output levels at their max as I did previously with the revo 5.1)

I obtained a strange graph that does not look like a typical response graph: a lot of 30db up and downs around +120 db

I followed the REW help file to do my measures and I don't understand the results
Can someone help me?
thanks in advance

PS: I do not know how to post a screen capture of the graph I obtained

[thewire]

Here is how to post a screen capture.

http://www.hometheatershack.com/foru...eady-post.html

Was the input level above -24dB FS on the VU meter when you were doing the setup in the settings window? Did you try adjusting the sweep level? Can you find something to protect your hearing such as some headphones you might use when mowing a lawn, foam ones, etc?

[brucek]

Then I plugged the microphone (Behringer ECM8000) to the phantom power (behringer ps400) and the phantom power output to the line input

The PS400 is a phantom power unit only. It is not a mic preamp, and does not output line level required for the soundcard.

brucek

[vvolant]

I bought a preamp this afternoon, I have better results
however I wonder if the response graph is correct and how to interpret it
I post a graph ASAP at the moment I have to take care of the children
Thank you for your interest