Wayne Parham Messages: 18787 Registered: January 2001
Illuminati (33rd Degree)
It's still OK as long as the insulation is not too dense. It shouldn't be too dense anyway, because that would not work as a damping material. What we want is stuffing that increases acoustic resistance as a function of frequency. It reduces midrange but bass passes right through.
You could always make one with R13 and another with whatever stuffing you're using and compare the two speakers to see if you find any differences.