One of our Avants rear speaker was crackling and the jets were much less powerful than those on the other car so we spent a morning investigating .Swopping the jets made no diff so we used an air line to try and clear any blockage and the seemed to be air escaping near the tailgate hinge .Off came the trims to reveal a kinked and cracked pipe probably cos too much line had been left out .This was splinted and sealed but then the drying out began cos all this testinghad shown where the fluid had been running inside the roof and down over the amp and speaker.All the trim foam and felt padding the amp and speaker had to come out and be dried and the water trapped in the well sponged out.It all took about 3 hours but our guess is that this had always been leaking since the pipe cracking possibly soon after it was kinked .So I suggest if your jets dont have enough power it may not be them that need cleaning just listen for water running inside
