Quote Originally Posted by vuki View Post
IMHO that high pass is too linear to be caused by passive component. I still think it's measurement setup. Try the Impulse measurement.
Thanks,

First measurement was done with IMPulse setting. The Impulserespose was measured with a log sweep. In fact to have ARTA determine if there are any excessive distortion components. At the level of my measurements these all appear to fall into the noise floor of the ADC.

The high pass can be acoustical as well. Think of the lower horn cut-off or bass reflex which both have inductive air-impedances in their modelling. Checking all bolts and nuts is also part of the setup inspection!

Coen