So, I built a set of rectangular drivers today, sized around 75x90 mm. I'm using .5 mm spacers with Stax normal (230V) bias, and a static-guard spray as coating.
The most obvious negative characteristic is that low-end distortion begins at higher volumes (a high, but not untoward listening volume). The high end does not seem to distort, or is masked by the more prominent low-end rumble. The distortion is unnoticeable at lower volumes, or with more mid-range heavy music.
What might be causing this distortion at relatively low volumes?
Any suggestions for how I might overcome it?
I'm finding the headphones fairly inefficient to begin with, so I may give a second coating of static-guard to begin experimenting.
Thanks in advance for any tips!