Subwoofers
 

I am looking to install 4- 8" Polk Momo's in my 25 Outlaw....what is the difference between dual voice coil and single? They will be powered with a Kicker 04KX 650.4, which is I believe 170watts x 2

Re: Subwoofers
 

Like the name says, SVC have one coil/speaker (2 terminals). Usually 8 ohms. This is powered by a single speaker channel (or 2 channels of a bridged amp).
DVC has 2 coils/speaker (4 terminals), usually 4 ohms each. These can be wired in a vaiety of ways, including 1 channel (right side) to one coil and the other channel (Left) to the to the other coil.
Gary

Re: Subwoofers
 

Dual voice coils provide wiring flexibility. Amplifiers produce higher wattages at lower impedances so you would connect two 4 Ohm voice coils in parallel to present a 2 Ohm load to a single channel amp.
For multiple subs, connect two 4 Ohm voice coils in series creating an 8 Ohm sub and then wire four of these 8 Ohm subs in parallel to present a 2 Ohm load to a single channel amplifier.
With a two channel amp you have the choice of either bridiging your 2 channel amp to create a higher powered single channel amplifier driving all 4 sub in parallel (my recomendation) or 2 channels driving two sets of 2 subs wired for 4 Ohms.
Confused yet?

Re: Subwoofers
 

A single voice coil has one coil(usually 4 ohms) and a dual voice coil has just that. 2 voice coils(also 4 ohms each).

The dual voice coil gives you more options for wiring. If you hook up one speaker to one amp and wire both voice coils in parallel you will have a 2 ohm load and the amp will have a higher output. If you wire it in series you will have an 8ohm load. When wiring several speakers to one amp sometimes you have to run a combination of series and parallel wiring to get the proper ohm load.

Re: Subwoofers
 

This website explains wiring in series and parallel very well.

Re: Subwoofers
 

The 8" subs won't have near the punch of high quality 12's. Dual voice coils are, in my opinion, a trend thing. No pro audio system uses them. That is, pro as in concert touring audio. They were originally designed to accomodate twin channels of a stereo system so that whichever ch contained bass, bass would be present always in the sub. Usually a passive crossover was used at the subwoofer feeding then to the full/higher range speakers. Two ch. stereo is "passe' these days with 6.1 and even 7.1 common. Most modern systems multiplex a line level sub output to a single "subwoofer" output, eliminating the need for dual voice coils. Best low frequency performance may be experienced running a dual channel amp in "bridge" mode and at a higher impedance giving an enhanced damping factor. Mechanically couple your subs to the boat body and you'll "feel' the bass more. Happy tunes.

Re: Subwoofers
 

Which model are you buying?
2 concerns: unless a speaker is free-air specified, it must be mounted in an actual speaker cabinet, the bench seat does not count. Not doing so can damage the speaker. 2nd concern: The amplifier is probably way too small for the application. And believe it or not but too small of an amp will damage speakers as well.
If you havethe db804 model, it has a program power rating of 180 watts and a SVC rating of 4 ohms or Dual 4 ohms. The MM2084 is rated at 200 watts with a single or dual 4 ohm coils. I am assuming you have the ZX650.4 since there is no KX650.4 that I know of. That amp makes 170watt X 4 channels at 2 ohms. It would fall a little short but not much on the 180 speakers. Buy the DVC speakers, wire the 2 voice coils together in parallel. Do this by running a jumper wire from the + of VC 1 to the + of VC 2 and do the same with the negatives. Plug the amp into either VC1 or 2 (it doesn't matter) One speaker per channel of the 4 channel amp. The speaker is now at 2 ohms thereby telling the amp to operate at 2 ohms and at 2 ohms the amp makes 170 watts. If you have to free air mount the speakers (meaning just mounting them in the bench seat, stuff the seat with life vests and so on with soft items as long as they don't interfere with the movement of the cone. Polk is suggesting a optimal speaker cabinet of about 1/3 of a cubic foot, this acts as a suspensions system and if you damage the speaker by free air mounting it, Polk might not honor the warranty.
You can PM me with any other questions you might have. Good luck!