Don’t laugh, but I had a lot of extra polyethylene foam (the kind used inside of life preservers) and a lot of extra carpet squares, so I insulated the cabin for sound. I cut pieces of the carpet squares a bit wide and bowed them up to secure them firmly. I also added a few dots of adhesive to ensure they do not fall or move. The carpet squares are very dense rubber and synthetic fabric and deaden the sound in the cabin considerably.
1978 Marinette 32 Sedan Flybridge 