odd test results

I'd be inclined to look at soundcard setup and input selection before condemning the mic, the response looks like it cuts off at 12kHz, internal mic inputs are sometimes sampled at half rate (e.g. 24k vs 48k nominal) giving that kind of response shape. Doesn't mean there isn't an issue with the ECM, but worth checking the whole chain.

Thanks John, I'm not sure where to check or if that is the problem because I'm using an Echo Mona ( in it's day it was pro gear) as a mic preamp with phantom power and line out to line in on an Asus xonar audiocard. I had made measurements last year and never had a problem and made no changes to the setup. I looked in both audio setups and saw nothing I could change.

Try ;

> Within REW ( preferences window ) increase the buffer sizes on your input & output sections .

> This approach ( recently ) fixed someone else's data capture which looked really quite similar to yours ( ie; inexplicable, premature HF roll-off ) .

<> :sn:

I did that and for 1 test I got the same results but now it is working normal:scratch: strange