@ErinH – First of all, congrats for your efforts at developing a speaker measuring rig at home. You've obviously put quite a lot of work into it. Keep up the good work.
I have one question regarding the Burchard S400's peak & dip at 500-600 Hz. It seems as if this might be resonance from either the cabinet or components. Is it resonance or noise? Or is it merely a variation in response? Do you have any thoughts about what might the source of that?
I tried following the lengthy Burchard S400 review on ASR, but it went on, and on… and on. After reading too many pages, I gave up reading around page 12. Perhaps you or someone else discussed this and I missed it.
On page 2, post #40, in the ASR thread, napilopez posted a graph, (shown below). He posted it again on page 11, post #214. It shows the frequency response curve of the S400 woofer (in red), the passive radiator (in blue), and their summation (in white). This suggests that the passive radiator or the cabinet contribute to this resonance. But there is no blip at 500-600 Hz range in the impedance vs. frequency curve that would be consistent with such a resonance.
