did i type "new the model" as opposed to "knew". grrrrrrrrContact the factory and ask for the T/S parameters for that driver, they usually hand that out for non-current models.
Secondly, the reason the woofer had the issue is that the crossover in the preamp for that channel is set too low. Make sure it is set to 'small'.
It's being overdriven and likely distorting a good bit, For that model 80Hz is the absolute lowest, and if you play loud, then set it to 100Hz, or even 120Hz.
As an example, I used 120Hz on the old Logos, and even my humongous SL3XC with 6 7" woofers that measure flat to below 40Hz at very loud levels, is crossed over at 80Hz.