feed back when using audio measurement software
I've downloaded REW and AudMeS audio measurement software and am trying them out using a Lenovo ThinkPad with individual ports for microphone and headphones, running Windows 7.
I've connected a shotgun microphone to the microphone input and connected the headphones output to the aux input of my stereo. I've placed the microphone right up to the driver of one of the speakers and run the test software. I assume the test software generates test tones via the headphones output, amplified by the amp and output through the speaker to be tested, and the microphone measures the signal in a graph.
It works, but somewhere in the setup the signal from the microphone is also fed back to the amplifier and causes feedback. Where is this likely to happen? In Windows? In the laptop? In the microphone input plug (3.5mm, 2-way mono plug)?
I've tried to disable the microphones and or headphones in the Sound option of the Windows control panel, but then the measuring software can't find them.
What's the trick?