Need Advice on Peavey Cabinet, I am new to Bass
 

I am new to playing bass, but picked up an older Peavey 215 cabinet with the square opening (ports?) in the middle of the cabinet, loaded with 2 15" Electrovoice 15L speakers. I have read that these speakers work fine for bass, but do not know this from experience, but I do know they do work for guitar well. This cabinet is the shallow 13" deep cabinet; I did note that they only have a small piece of fiberglass insulation inside. My question is this: Should I use the acoustic foam sheets (like they sell @ partsexpress) to help dampen the standing internal frequencies ?? All advice most certainly appreciated !!!