I've always been somewhat skeptical of my speakers water integrity and have made sure that where they are fastened to the wall that there is no water intrusion along that joint. But are you saying that if the speaker cone is damaged that water can leak into the trailer wall?
How did you notice the speaker cone damage - what are the clues to look for?
There's lots of advice and information in forums... sometimes it is correct. For example, all of my posts are made by a political appointee who got the job as a reward for contributions to my diesel bill.
2011 Jayco 28.5RLS; 2008 Chevy Duramax; Pullrite Superglide Hitch