http://www.wakeworld.com/MB/Discus/messages/3183/637908.html?1224818149 Similar discussion. I posted some pics of the XS-650.
When comparing. Make sure to look at the build of the speaker. As many that were mentioned are not marine. Most will say if it is a plastic cone and rubber surround, you will be fine. But that is only the case for the front of the speaker from the occasional splash.
A tweeter on a pole piece can get water down the pole and into the voice coil and have failure there. A lot of car audio speakers have a stamped steel frame. And exposed magnets. Another point of failure.
As we have all wound up putting a cover on a wet boat and seen what the condensation build up can do. That is everywhere in the boat including the back or the speaker.
I have even seen some companies trying to promote in boat speakers as marine that have stamped steel frames and exposed magnets and open pole piece tweeters.
Which goes to prove that there are many companies that are just trying to make a buck and do not fully understand what it truly takes to build a marine speaker.
Many people have used car audio speakers in boats for years as there was not any high performance marine speakers on the market. So there was no option. There are plenty of options for a high quality marine 6.5 inch in boat coax today.
Of course I am biased, but I feel that our Wet Sounds XS-650 is the best performing in boat speaker on the market. It can play louder and handle more power than many other speakers on the market and is truly a marine speaker.
After that, there are other marine speakers to look at from other audio manufacturers. JL, Kicker, Rockford, Alpine.
But my suggestion would be to try to look for something in a marine speaker. Then after that, see if you can do a demo on a couple that you have narrowed it down to. Try to do a demo with the RMS ratings of each speaker.
Hope this helps and let me know if you need a Wet Sounds dealer near you. Might have one that can do some demos.
Tim
Wet Sounds