jasonmd2

So the 10's didn't sound awful in open space? I'm putting them under the rear bench so in a sense they'll be closed in but by no means sealed. I suppose I could also do a box. There were 12's in there boxed before and they fit. It's just that the box took up some of the storage space under the seat.

Okay, so basically just put two speakers positive cables to the each positive terminal and two negatives to each negative terminal thereby doubling the amount of speakers off the amp...is that correct? Then the amp will be pushing a 2 ohm load and according to the specs it's still 150x4 at 2 ohm so basically all eight speakers will be getting 150w? Won't that put too much stress on the amp, overheat it or something?

As you can tell this stuff is a little foreign to me

hotjava66

I also have a similar setup, and yes you could run all 8 on a 600/4 as stated above, two speakers to each channel, in parallel. The amp is 2 ohm stable but you will be working it harder than at a 4 ohm load. If you have the ability I would run 2 amps. I have 3 ten inch IB's under the back seat powered by a 750/1, they sound pretty good. As another poster said, not quite as good as a sealed box but very good. To make my back seat more "sealed" I used a velcro kit from a tonneau cover to "stick" the seat lid to the base, made for a tighter seal, better sound, and no rattling. Plus it doesn't bounce off in big water, added bonus.

4bus

That amp will run fine at 2 ohm, in fact it will run at 1 ohm all day. If you have an overheating issue or the amp is clipping you can also run a pair on each channel in series and bump them to an 8 ohm load. IMO hihg quality amps always perform better bridged, its free horse power waiting to be unleashed.

Run one speaker wire from the amp for each channel, then bridge it from one speaker to the next. Like this http://a248.e.akamai.net/pix.crutchf..._4-ohm_2ch.jpg

Or 4 speakers on each of the two channel for a 4 ohm load
http://www.rockfordfosgate.com/rftec...4&woofer_imp=1

Here is a wiring guide, its for subs but same same. Select how many per channel and go. Play around. Most speakers are 4 ohm load, but you can order many at 2 or 8 to fut your application.

http://www.rockfordfosgate.com/rftec...okieSupport=1#

Don't forget a good quality CAP, it will keep the sub amp from robbing power from the mid/high amp....cleaner sound

jasonmd2

Thanks 4bus for the great info!

So based on the above info would this work? Run everything off 1 MHD 900/5? And please no comments on my artistic ability...or lack thereof!

4bus

Should be fine, I have my Soundstream 5 channel wired the exact same way, plus my subs are DVC so they are at 1 ohm, no issues and it plays for hrs on 2 batteries

Griff

Wiring that way is correct and you will get a 2 ohm load on the amp, but you will get 75 watts to each speaker. It will not stress the amps. They are designed to stable at 2 ohm loads. Both the JL and Alpine PDX amps put out more watts than what they are rated at so you will really get more like 80-85 watts to each speaker.
I have a PDX 4.150 running all 8 of my DC Golds(rated at 80watts rms/300 watts peak) and it is plenty of power.

Personally, I would use one amp for the speakers and one amp for the subs. The PDX amps are very similar to the MHD's and you can pick up PDX's on ebay for a lot less money than JL's. The way they are made, you really don't need "marine" amps. The automotive versions cost less and have more power options.

ChargeIt

Some thoughts.......

You will lose significant bass going from two 12" subs in an enclosure to two 10" free air.
The recomendation for 4 10's would stay closer to the existing sound level if that is a goal?

Your first plan for two 600.4 delivers the power needed for 4 pairs of speakers and leaves some head room.
The Class D computer controled amps like JL and Alpine PDX eliminate the benifits of running lower Ohms, just increase wiring flexibility. If only one 600.4 is used, yes the load will be 2ohm but the computer makes changes. Net result, each speaker will only receive 75w.
No extra power is delivered like tradtional A/B amps that effectively double power.

As for subs, a 750.1 may be a better route than another 600.4. Less $$ and more power. A third 10" FA could be nicely run with that amp.

It sounds like you are pretty set on brand and it rolls off the tongue sexy to say the system is 100% JL but have you comparatively listened to other combinations?
To my ears, the JL speaker / JL amp is too controlled/muted for open air boating. They sound great in a car or in a quiet demo listening room but lack in the noisy, open air of a boat cockpit with wind noise or rafted up.
Seeing you are in FtLauderdale, there should be several quality stereo shops to explore options. Again picture in a noisy environment listening to the type of music and volume you will be playing, not necessarily a fine jazz track that the sax sounds incredible.

I like the white grills that blend vs black on white vinyl, personally.

US1 Fountain

I ran 2 of the JL 10" free airs in my Fountain off a JL 250/1 amp w/o any issue. With 2 pairs of Baabs (now DC Golds) off a JL300/4. Sounded great.

For the cruiser, I went with 2 pairs of 7.7's coaxials and started off with a 10" free air in an oversize storage compartment. Sounded great according to everyone else, but you know how us as the owners are, never sounds as good as we want..
2 weeks ago I replaced the free air with the infinite baffle sub, and also reduced the enclosure to 1 cu.ft. Hits harder now.

As far as Dc Gold (Baabs) vs JL, I'd be hard pressed to put 1 over the other. Both are amazing sounding speakers

jasonmd2

Okay, thanks again for the responses! I'm a little more confused now, lol. Seems like a lot of this might be preference too. I don't want to over think this, I'm not trying to blow the ear drums of everyone at the sandbar...but of course want it to sound good and loud.

Couple more questions. What is the optimal power to put to the 7.7's? I see their range is 40-175 and continuous is 100w...so does that mean 100w is best? Or would the 150 that the 600.4 puts out be better? Same scenario with the subs...range is 75-250 and 250w continuous, so if I ran a 750.1 that would put 750w to each sub or 375? And if high end of range is 250 then would I just turn the gain down to keep it under the 250w high range?

Since I'm most likely not going to change my amps right now I will probably go with 2 600.4's for the 7.7's and then another for the subs...I'm just trying to better understand the logic behind the wiring of it all so I can assemble the best system. The sub amps got me confused...why isn't anything a 2 channel? Wouldn't that be logical for a sub application?

Griff

Sub amps are MONO, meaning they have one channel. I run a 4 channel amp that is bridged to 2 channels and then the switch on the amp is set to MONO for my subs. i already had the amp, so rather than replace it with a mono amp, I wired it and set it to work for what I needed.

There are lots of ways to wire stuff and its relatively simple to experiment with different wiring configurations. Also, if you plan ahead, there are ways to do stuff in various stages for future upgrades.

I would go with a 600.4 amp to power the JL's. You could easily hook up one to all 8 speakers now and then add another later if you think you need more power. The amps have switches and settings that will easily allow this.