Running 2 10" MTX Marine subs powered by a Kicker 700.5 amp and they sound very good. Not competition good, but great for everyday use.

Wanted to chime in to say that DC Gold (Formerly Babb) are the way to go for marine installations as far as I'm concerned. They sound great and they are very efficient so they don't need a ton of power to get loud.

The biggest factor is that they're waterPROOF. You can hose them off if you need to. Most other speakers on the market are water resistant only.

In my U17, I'm running an Alpine PDX-5m driving two DC Gold 9.5s up front, two DC Gold 7s in front of the rear seat and a 10" Infinity Perfect sealed. Really impressed with the Alpine amp as well. My birth sheet says it outputs 100x4 + 360x1. Amazing they can get that much power out of such a small footprint.

Back to the DC Golds, for tubing/rafting in the summer time, I built a cooler stereo using Babbs which is what turned me onto them. 100 quart cooler with a cd player, Crossfire 250 watt amp, battery and two 10" Babbs. It sounded great and worked really well for tubing in the Ozarks. Got wet and never had a problem.

Been running the Polk Audio Momo MM690's and they have held up very well. Have them hooked up to a Clarion APX280M amp along with a set of Clarion 7" speakers. Also run 2 10" Sony Xplod marine sub's hooked to a Audiotek amp.
Upgrading this year and just bought a Alpine PDX-F6 along with 2 pair of the new Polk Audio MM691's. For the price, durability and sound you can't beat the MM series from Polk.
Have never heard the DC Golds so I can't say they are better. I abuse the stereo at the beach for hours and I can say batteries is the big thing to keep everything sounding good.
Plan for set-up this year.
-Alpine PDX-F6 150 watts RMS X4 all digital running 4 Polk MM691's in external boxes to put out on the bow while at the beach. Added the bass control to the amp also.
-Clarion APX280M running 2 pair 7" Clarion's and 2 6.5" Clarion's (2 ohm 115 watts) inside the boat
-Audiotek SuperStock amp running a pair of 10" Sony sub's
Should have everything up and running by next weekend, can't wait to heat that F6 go to work!!!

speakers
 

Im have Alpine pdx amps and infinty Kappas speakers w/o subs and the sound is unbelievable.In my Top Gun at the bottom of front seats i have 6x9 with excellent base and 4 6.5 in front of all seats on sides and my 572/700hp engines are not that loud anymore as I crank up the stereo.SO thats inexpensive and top of the line equipment.

Per AUDIOfn's recomendations.....I just ordered 3 pairs of DC Gold N69C 6x9" and 1 pair N5C 5.25". These are replacements for Boston RX97 that are 10-15 years old (non marine). I already have (and don't intend to replace yet) three 12" subs. All are powered by four Alpine V12 amps. Not sure who makes these subs.

I have 5 1/4's and 6x9's Babbs in the Fountain and have always thought them to be hard to beat.
Just put in 2 sets of JL 7.7's in the cruiser this past weekend. Those can be cranked all the way up and are as clear as can be. I give the edge to the JL's over the Babbs (DC Gold)

depends on budget. I didnt have a ton of money and bought Pyles. Sounds good and have good construction.

1st boat 1 set JL audio VR 6.5 components + 1 set infinity coaxials + 2x 12" W6s custom sealed box powered by 1000/1 and 300/4. This system sounds awesome, but the VRs are not indestructible.

2nd boat 4 x JL audio C5 6.5 + 2 x 12" W6s in a custom sealed box Powered by 1000/1 + HD600/4. The sound quality stays amazing at ludicrous volumes. The HD 600/4 uses the same or maybe even less power than the 300/4

3rd boat 4 x JL 7.7 marine component + 2 x 12" W3 + 1 x HD 900/5


JL Audio is extremely reliable and most of their amps make full power all the way down to 10.8 volts.

+4 on the JL Audio I have 2 12" boxed subs with their own 500W JL Audio amp. 2-JL 6x9's, 4-JL 6.5's on their own 300W. The subs are in the engine compartment and when I crack the rear deck it gets hard to breath at full volume. I actually had my brother in law on the next block tell me he thought his dishes were going to break. I play everything from Eric Kunzel Time Warp to Led Zepplin. This system is amazing, super clean, and the only thing that can play the 33Hz bass in some of the Eric Kunzel pieces.

Need amp HELP!!!
 

I've got 4-8" menphis audio on a JL 360/4 not sure they have the power they should ??? & i just put 4-8"Rockford Fosgate in the rear . Is there any amp out there that would push all 4 of the RF any suggestions ???