Re: 4 wakeboatd tower speakers, is an amp 100% necessary
Installing stereos is really a snap. It's mainly all in the planning and execution using the proper installation accessories. If you're running 4 other speakers in the boat off of the deck power, then yes.. you'll absolutely need an external amp to power those tower speakers.
Locate a place that's as out of the weather as possible and close to your battery if you can. Under the rear bench seat is preferable due to not being in the heat of the engine compartment and being close to the battery. Under the dash is another good area.
Grab yourself an MB Quart NAU460 -
http://www.amazon.com/MB-Quart-NAU4...N4WC/ref=sr_1_1?ie=UTF8&qid=1336669001&sr=8-1
You'll need two runs of 8 AWG marine grade cable, tinned 8AWG crimp ring terminals, an inline fuse holder + fuse (
http://www.amazon.com/Raptor-GFBW1-...XMIQ/ref=sr_1_3?ie=UTF8&qid=1336658819&sr=8-3 +
http://www.amazon.com/DB-Link-AGU50...1?s=electronics&ie=UTF8&qid=1336658858&sr=1-1), a set of good quality shielded RCA cables (
http://www.amazon.com/CL17Z-Competi...?s=electronics&ie=UTF8&qid=1336658879&sr=1-11), some marine primary wire and some copper clad aluminum speaker wire (
http://www.amazon.com/Mediabridge-G...2?s=electronics&ie=UTF8&qid=1336659246&sr=1-2).
Cut yourself a positive and ground cable for the amp. Crimp the ring terminals on either one for the battery connection. Put the fuse holder within 18" from the battery on the positive cable. Run the RCAs from the deck to the amplifier. Find a free accessory switch that puts out 12V+ and use that as the remote turn on wire for the amp and run it back.. or.. use the blue/white wire coming out of the deck that will put out 12V+ when the deck is on, and run that to the accessory switch. Run your speaker wires through the tower if you can.
Note - you don't have to do the accessory switch for the tower speakers if you don't want to.. it's just a suggestion so that they don't always have to be on. Those things PROJECT sound like crazy and there will be many times where you don't want them screaming at everyone else but you want the music down low in the boat. If you don't want the switch idea, then just run the blue/white wire straight to the amp as the remote turn-on wire.
Use this quick guide for basic amp tuning.. just nevermind the bass part of it as you're only running high pass speakers. (
http://forums.iboats.com/showthread.php?t=546534)
Need any help, just ask.