What a wealth of information here. I was just curious in what had been done to Valkyrie's crossovers. You guys sure do pretty work. About the foam material. I am assuming it is some type of open cell foam. I measure it to be 1/2 in thick. Hand cutting the foam from sheets with a template may be possible, but the pictures I have seen have a camfer around the driver opening. This could be problematic to reproduce. Maybe a jig with a router? Anyway I am thinking this may be acceptable material to use.
AR-91
in Acoustic Research
Posted
I just measured the PPI of the original foam on an AR90 and it looks like 28 +/- a pore ...