HI, I'm trying to measure the spectral response of my car stereo using
an extigy connected to my laptop. I have some software that will
generate a signal and then measure the response. The problem is that
there is "response" even if the microphone and speakers are
disconnected! That is, somehow there is like 100% "crosstalk" between
the output and the input. It seems the volume sliders on either mic in
or line in don't do much. Also, the same thing occurs if I use the
built-in soundcard in my laptop, which suggests a setup issue rather
than any actual problem. Any advice?

Also, if I actually try to hook up the output from the extigy to my car
audio, I get a really loud hum and absolutely no signal coming through.
I have no idea how to fix this.

thanks
ms