Mounting amps in my boat - the stereo winter project

[bergermaister]

LAS responded this morning - the difference in the MM651 and MM651UM is that the UM's have the crossover built right into the back off the speaker at the magnet. Not external like the standard MM651. Ah ha! Surprised I missed that. I had to stare at the drawings in the installations guides for a minute or two before I got it. Polk's website nor Crutchfield, etc. have any good pictures that show the difference.

At any rate I am planning to run my LAS Polk MM651UM doubles with a Kicker 350.2 (2 channel amp). Since the doubles are wired in parallel they will draw 2 ohm. Each speaker is rated at 100watts so I was told to get amp power to match the total number of speakers.

At 2ohm the Kicker 350 will push 175watts per channel = so each set of doubles will be getting 175 watts, well within safe range of 200watts per pair, or roughly 87.5watts per speaker.

I only have four cabin speakers in the boat so the 4 channel amp is an easy one. As mentioned earlier I'm running the MM651's in the cabin as well but will only be pushing 60 watts per channel to them from the Kicker 350.4 at 4 ohm respectively. The reason I went that route is I'm thinking more power = more volume to the tower speakers, and a little less power = less deafening in the cabin...

I'm no stereo expert though - I've been researching this all out as I go and asking lots of questions.

[mustangairchair]

i mounting it on the right wall there is a 1x1 piece of wood around the boat you can screw into with out going through hull with the right lenth screws. here is a picture. there all off the floor and mounted tight.

[bergermaister]

I've read that you can toast the remote power lead from a head unit by trying to power on too many accessories/amps with it. The recommendation is to use a relay - Single Pole Dual Throw or SPDT.

If I understand this correctly, you wire all amps or accessories to the relay as indicated, a dedicated 12v power line, and then finally the remote power lead from the deck. The remote power lead hits the relay when the deck comes on and the relay acts as a "powered switch" to make sure that all amps/accessories have sufficient juice to come on as intended.

Anyone else using one of these with a multiple amp setup? Am I paranoid and the deck remote power on lead will do just fine to kick everything on?

Thanks!
Berg

[newty]

Is your stereo on a switch? If so then wire it into the switch. Otherwise I would wire the amps to a relay. I have burned out the remote on a deck once. So I use relays now.

[bergermaister]

Thanks - My stereo is actually wired hot all the time so I don't have to have the ignition on or hit a switch. Just remember to turn it off when done. I haven't noticed any battery draw when it's just when sitting.

I wired up the amps to the deck with a relay in between; works like a charm. Luckily I added an extra hot line off my power distribution block so it was a pretty easy setup. Hit the receiver, all three amps come to life with an ominous red glow through the Kicker logos!

I've posted some pictures of the installation progress so far in a new album under my profile. (https://forum.moomba.com/album.php?albumid=136) Still a bunch of shots stuck on the camera and I'm getting too tired to do anything more with it tonight. Fun stuff though. All the planning, research and asking questions is paying off. Have a lot of fun with it but taking my time!