I performed the measurements on my bass-reflex loudspeaker according to the steps outlined in pengray's writeup at the beginning of this thread. I may have a soundcard or calibration issue. I have a Realtek HD on my HP laptop. I performed the calibration and it seemed to go fine. I'm using a Dayton EMM-6 mic and loaded the calibration file. I checked the boxes for calibration. The bass response seems much better than the plot indicates, and I have no idea what the rise in the tweeter plot is at around 350Hz. I set the start frequency for the tweeter plot at 500Hz. As a test, I connected a signal generator and when I pump 350Hz into my tweeter, there is hardly anything at all generated. As I approach the crossover frequency for the tweeter, the response seems to come up where it should. My crossover is a passive 2-way 12dB Linkwitz-Riley alignment at 2100Hz. It also appears as though my calculated crossover frequency is wrong.
I meant to mention that I am using a Behringer phantom power supply in-line with the mic and a Shure impedance matching transformer to input the signal to my mic line-in.
Any ideas? I have attached the plot.