well spotted - I do have a cheap cover on it but some water does get in. The membranes were actually the best I've ever seen on a mk2 and mostly intact - but I removed to check the bottoms of doors, clean out and spray with light cavity wax (ensuring drain holes are clear afterwards) I've done a few membranes over the years and still trying to work out the best solution - I've got some 50mm wide 3M double sided tape which seems to work reasonably well but I've also tried tucking the lower part in - so it sits on the inside of the panel and any water can't run between the plastic and metal. I re-use the original membrane if it seems OK, but have also used poly sheet and even damp proof membrane in the past
A good soution is butyl roll. Tacky as hell. It also helps prevents water passing onwards and allows the membrane to be removed without damage. Its what I used. I also do a double skin method with the membrane. One sheet droops inside the door for run off. The other goes on the outside. Nothing gets past that set up. Test with a hose before putting door card back on.
Nice idea to put a second flap to drop behind the frame. When I've tried to use a single sheet of plastic sheet it crinkles at the point it tucks in. Has anybody got measurements / a template for cutting a membrane from sheet material?
Oh, another thing. When you route the cable into the speaker make sure it's coming up from the bottom. The reason being any water tracking down the cable inside the door drops off the loop not through the membrane into your speaker. Take a look at how they route TV ariels going through external walls, same principle. Also you can fit the replacement membrane "baggy" so it's one piece rather than glue those original pockets in it. Hope this helps.
