Stereo changes

[paratrooper39]

Hey all,

So some might know, I bought a 2015 AR192 this fall at the end of the season and I'm working on changing a few of the things I didn't care for, before the new season starts. Today's question is about stereo/sub/speakers.

The boat came dealer installed with the slampak, for those who aren't familiar, 2 7.7" JL coaxial speakers and a 200w amp.

I'm wanting to add a bazooka tube, which I posted before, but I was looking at the preloaded ones and then it hit me that I already have an amp in the boat. Can I simply run the passive bazaooka tube off of this amp or is a 200w really only enough for the two tower speakers?

I also purchased a M505 and two wired remotes that I'm having installed because I couldn't stand the stock headunit.

 

[David Analog]

There are many ways to drive a single subwoofer and a pair of fullrange speakers off of a single two-channel amplifier. In order to control the impedance from dipping too low you would need passive crossover components which are expensive (in the case of a large enough inductor) and adding these would incur significant insertion losses.
Also, in order to have good sound quality it is important that the subwoofer and fullrange speakers do not overlap in their frequency range. And this requires two amplifiers, or three total channels, with both high and lowpass active filters.
I would discourage running the 7.7s off the HU power to free up the amplifier to drive the sub. Both need to be driven by external amplifiers.
So you need another amplifier.
Bazooka does make tubes with built-in amplifiers but these are normally BTL amps running a DVC woofer and the power is anemic.
A Bazooka bass-reflex tube is a fair product when used correctly, as in direct radiating and loading off a corner or surface. However, you end up having to conceal it inside a console or locker and that places it in a very compromised location.
I would recommend a JL Audio 10-inch IB woofer because it is direct-radiating, and a very good sub (provided you have the right location available on your boat).

 

[paratrooper39]

@David Analog thanks for the in depth answer! Maybe you can answer why the boats don't come stock with a small amp for the interior Polk speakers? It seems from what I've read they really should have one. Per your advice I'll keep the towers running off of the amp that came with them as part of the slampack and decide on another amp. I liked the idea of the bazooka tube because it wasn't exposed and I always feared that when you put one in the fiberglass it would rattle and vibrate the fiberglass too much, maybe I'm wrong. So back to interior speakers, how large of an amp is needed to power these correctly?

 

[David Analog]

39,
Powering the inboat speakers off the HU rather than an external amplifier is no doubt a cost management issue, common to all boat manufacturers.
Concealing a subwoofer will cut about 75% of its output at some frequencies which means you have to work the amplifier and woofer much harder. And that is never a good solution. If you do conceal a subwoofer you need to cut in an aperture/vent no less than equal to the surface area of the woofer. It's still a compromise but much improved versus no vent.
You should not have any rattle or vibration transmitted through the boat structure, IF, the installation execution is done correctly and if you use the correct woofer, which would be a true infinite-baffle high-'Q' woofer....like the JL Audio offering.
With a tower amplifier and a sub amplifier, you will never have full zone control while powering the inboat speakers off the HU.
A good amplifier to drive a single sub and two pair of basic 6.5" coaxials would be the JL Audio XD500/3. The PASMAG independent test report shows this little amplifier delivering about 675 watts.
Get with Odin @ Earmark Marine. He's an authorized on-line dealer for JL Audio,Wetsounds, and much more, and he knows the marine audio category and installation techniques better than anyone.