@fraserjr - Sorry for the long post but I think you and perhaps others will find it useful. Unfortunately overcoming wind and motor noise in an open environment like a boat takes considerably more decibels than in a closed environment like a car. Speakers are better able to to produce clean and louder sound with the appropriate amount of clean power and the stock head unit does not even have enough power for the speakers that are already there. If your goal is being able to hear the music at cruise I recommend going with a 4 or 6 channel class D marine amp and hooking up the existing cockpit and/or bow speakers to the remaining channels after adding the the new pair. everything will be louder and cleaner that way. If you are trying to do this on a budget there are mid-grade marine amps out there like Kicker, JBL, and MB Quart that will do a good job for the small load you are looking at running. I recommend staying away from the true budget amps out there like Boss audio or Pyle and the like. In fact this one may be a good mid grade choice
https://www.amazon.com/NA540-6-Naut...82419254&sr=8-3&keywords=6+channel+marine+amp . My reasoning on the 4 or 6 channel is that the install gear is going to cost you quite a bit of money and then there is your time since you are already at it so why not spend a small percentage extra and get a large percentage more bang for your buck. All of that said I personally will only use JL audio amps but they are expensive.
In case you have not read it on other threads already wire is very important. Don't use a kit from Walmart or Amazon. Only use good pure copper or tinned copper wire (don't believe everything you read on the package or marketing either). I found what is the very best marine power wire out there at the best price at
http://www.knukonceptz.com/marine-audio/marine-power-wire/ . Their Kolossus Flexs wire is the best stuff you can get and half the price of the Jl Audio stuff which is exactly the same. Also make sure you get the right gauge of power wire for your load and length of run. 8 AWG may power a single amp at the helm but it would be cutting it close so 4 AWG would be the better and much safer way to go. Also make sure to fuse the positive power lead in line as close to the battery as possible (knukoncepts sells these too). You will also need an rca cable which is also available at you guessed it; knuknoceptz. I also recently discovered that In wall CL-3 speaker wire is great for a boat and certainly better than most other speaker wire while being very cost effective. Knukonceptz speaker wire is a better choice as their speaker wire in tinned but perhaps a bit more expensive. I like 14 AWG wire for most speaker runs with the exception being 12 AWG for subwoofers.
Yes the price all adds up but the old acronym concerning BOAT ownership is very true (Break Out Another Thousand). My recommendation above won't come close to winning any competitions or even bragging rights at the local ramp but it will get you a decently good sounding system that is also safe and won't fail down road if installed properly.
One install tip for the the speakers you are adding is that this hole saw kit from harbor freight makes a perfect 5 inch hole (exact mounting hole needed) in the fiberglass for cheap
http://www.harborfreight.com/34-in-5-in-carbon-steel-hole-saw-set-18-pc-68115.html . Tape off the area with painters tape, drill the pilot hole in forwards then switch to reverse to get the saw through the thin gel coat layer then back over to forward to get through the fiberglass. Put the speakers in the 5 inch holes to mark the 4 screw holes of the speakers and pilot drill those out. Pilot holes in fiberglass need to be close to the final screw size you are using like cabinet grade hardwood. If you get the speakers from
@2nazt you may ask him to make sure to include the gold plated female wiring spades that I included in the box as the db651 are an odd size and I ordered those separately (that is unless you prefer to solder). Lastly or rather firstly don't forget a good dust mask, googles, gloves and work clothes as cutting fiberglass is nasty.
Good luck.
