As I stated in a different thread, the inside cabinets of my 1.2 TLís were not completing hot glued in all of the inside corners and they were leaking air like a sieve from various other locations as well. However, after sealing them up with hot glue and applying Mortite thereís been a dramatic improvement in bass response.
Hot glued areas: All inside corners and cross braces; the 8 nuts that hold the end caps on; the end of the cardboard tube for the bass brace.
Applied Mortite and Dynamat to the MWís, passive radiator and crossover plate.
Replaced the 8 wood screws in the PR with #8-32 threaded inserts and cap screws. I highly recommend gluing the threaded inserts into the MDF as Richcando suggested, taking care not to get the glue inside of the insert.
Disconnected crimp connectors from every MW and tweeter, applied Deoxit Gold, and then reattached. Disconnected the wire harnesses, applied Deoxit Gold and then reattached.
Now thereís bass!!!