Boat Audio Questions

[dannyhightower]

After reading this forum I've purchased 2pr of MMC6500's for my boat but with this I have a few issues... First let me tell you about my boat and system. The boat is a 22ft Baja thats a closed bow with small cuddy cabin up front. In the nose of the boat I have two Fosgate 15's in a sealed box built into the bow. These have a Punch 800 amp powering them. This is connected to a new Alpine HU. The MMC6500's will be mounted in the main area (outside the cuddy). They will be replacing several pairs of 6x9's. Currently poweing these 6x9's are a Fosgate 4 channel @50w per channel at 4 ohms. Now I could use this amp to power the 6500's but,,,

#1 is the Fosgate 50x4 enough power and clean enough for the 6500 considering they are in an open air environment?

#2 If purchasing new amp or amps for the 6500's should I consider biamping for this boat system or is it just a waste (because its a boat) If it is a valid consideration I see there will be pros's / cons to it.
Pros = more power to each speaker, louder, more efficient
Cons = more amps per speaker = more power drain from batteries
= more cost

#3 If I were to biamp why wouldnt I just use the active crossovers for both the mids and highs and not use the included Polk Xover for the highs (as instructed in the manual)

#4 If I should buy a new amp should I use the POLK 400.4 or try something like a Hifonics Olympus 125x4 @4ohms??

Thank you in advance for taking the time to answer all of this! :)

[Dennis Gardner]

Was it loud enough before? If not, I doubt reducing the number of speakers will increase the volume of sound.

I would expect it to be cleaner, but not louder.

[DSkip]

Welcome to polk audio. May I ask what made you decide on the momos?

[DSkip]

The warranty on the speakers is void if you power the momo's without the passive crossover, unless you are using the c400.4. They designed that amp specifically for the momo's so in that case you could just run it without the passive.

So if you were to go with the c400.4, then no passive, but the hifonics, you would need the passive. Its just a precaution for polk not to have to spend too much money on repairs for people who dont know how to set an amp correctly. I run my c6500s without the passive crossover on my mtx amp, but then again they dont have a warranty so I lose nothing by doing so.

The c400.4 will be easier to tune because polk has already done this for you with the active crossover. At any rate, biamping allows more tunability for the speakers.

As far as the fosgate amp, since you already have it you could install the momos and attach them to the amp and see if the loudness suits you. If you wire that amp to a 2 ohm load per channel it would produce the right amount to power those speakers.

[dannyhightower]

It was great to wake up this morning and find 3 people trying to help. Thank you!

A little more background:
Back 15 years ago it was all about volume with the least amount of costs. That meant 4 sets of 6x9's with the two 15's :eek: Then 7 years ago when I bought the Baja I had all theses speakers sitting around so I installed 3pr under the rear bench seat and another in the factory 6.5 locations. Overall it ok but the SQ was not there (embarrassing).

So this summer I wanted to go for SQ #1 and volume as the second priority. I replaced the $79 HU with an Alpine and bought the MMC6500. Why the 6500's? Because:
They were Polk’s (great quality)
Marine rated (important to my install location)
Got terrific reviews & multiple recommendations from this board and others
Got them for 179.99a pr with the factory 3yr warrantee.
I can buy 1 or 2 more sets later and add them to my great install location which will be incorporated into upholstery and hidden. (While not affecting SQ)

So for my situation...
Will I be able to tell the SQ difference with Biamping?
Will it help make it noticeably more volume?
If I could get the 400.4 for 315.00 with warrantee should I get 1 or 2 (one for each set)?

Thanks again everyone

[DSkip]

You can notice the SQ pretty easily. For instance, I found that the tweeters are just a little too piercing for my ears. When I biamped the speakers, I can adjust the driver and tweeter gains separately, allowing me to keep the highs under control. Im very pleased with the sound now. Also, my head unit allows for crossover controls for highs, mids, and subs, and by biamping I can use these controls.

The volume wont change so much since the speakers will be getting the same power going to them. It will just be much cleaner sound, as you can adjust crossovers and gains separately.

As for buying 2 of them, thats entirely up to you. I would run that amp you already have and see how you like that; just run all 4 components off the 4 ch amp and see how it suits your tastes. If you aren't happy then, biamp them with the passive crossover and listen some. If youre still not happy, go pick up one of the c400.4s and see how that works biamped. Then again, I don't have a job so I am all about saving the money.

[dannyhightower]

In theory if someone were going to biamp the MMC6500's wouldn't using an active crossover on the mids and a second active for the tweeters be better than using the supplied passive for the tweeters? Does anyone have recommended xover points for these?

I also like the thought of running the system at 2ohms. My only concern is the amp getting too hot. Its over 100 degrees here in Texas and this system could be playing in those conditions for extended periods... Suggestions?

[HiPerf360]

I think bi-amping your components in a boat is overkill.

Make sure that you use a quality marine rated amp.

[dannyhightower]

Thanks HiPerf, Can you tell me why you think that? I'm really caught between doing it for SQ but dont know if the environment is going to negate the potential benefits.

[HiPerf360]

you nailed it....

The enviroment in a boat is totaly different than a car or home, the difference you will notice is not worth the extra time and expense of bi-amping

[DSkip]

Thats why I thought itd be best just to run them off that fosgate amp and get a feel for what youre getting with that before you jump off the deep end and invest all that money in new amps. Might end up content with that and have a few more bills in your pocket.

[lsutigers]

I think bi-amping your components in a boat is overkill.

Make sure that you use a quality marine rated amp.

If anyone is looking for a quality marine amp and speakers for that matter, check out MTX's new Thunder Marine line. I just bought 2 pairs of MTX TM6502 6 1/2" marine speakers and the MTX TM904 4 channel amp and it sounds amazing. I bought all all the stuff at Circuit City, as far as I know, they are the only place carrying the marine line right now. The best part is they had it all in-stock locally, they now carry marine electronics in the store.