6 speakers with (2) 4-Channel Amps??

I currently have 4 in-boats speakers running on one 4 channel amp.

1 set of speakers are mid boat, right next to the drivers and passenger seat. The other set is front of the rear bench, on the sides of the boat.

I would like to add 2 more speakers up in the bow.

All speakers are Polk Audio DB651's and both amps are Cadence SQA-4's.

What would be the best way to wire all this together? Which amps should be running which speakers?

I was planning on leaving the rear 4 as they are and bridging the other amp for the fronts??

These 6 speakers will all be running on the front channel as I also have tower speakers.

(Message edited by ship_of_fools on December 07, 2009)

I would just make it easy and add 2 more speakers (8 total).

That is an option too.

I have 4 extra Polk Audio's (from upgrading the tower speakers) and the 1 amp. Just not sure where I would put the other 2 speakers??

Just thought I would hold on to them for spares.

If i'm reading your post right, you have 4 cabin speakers and 2 tower speakers currently running off two 4 chnl amps.

Ok, without looking up the specs on the amps, or knowing what tower speakers you have, here is what I would recommend you do with what you have: Wire the 2 bow speakers to chnls 1 and 2 of one of the 4-chnl amps. Next, wire the 2 port side main-cabin speakers in parallel to chnl 3 and do the same with the 2 starboard side on chnl 4 of the same amp. This leaves the 2nd 4 chnl to power the tower speakers.

I actually have the tower speakers on their own amp. I updated the tower speakers to HLCD's and got a new amp for them. I used to have the SQA-4 and the Polk Audios on the tower. Now they are extra, so I thought I would add some speakers in the bow.

I also have a 12" Wetsounds sub running on another amp.

I am leaning toward just bridging the 2nd SQA-4 and running the bow speakers off of it. Does that make sense? Or, would it be better to bridge one set of the cockpit speakers?

Ok, the SQA-4 does 100W's x 4 @ 4 ohms, 150W's x 4 @ 2 ohms, and 300W's x 2 in bridge mode. So, if you ran the pair of bow speakers bridged, that would be 300 watts RMS.....I believe your polks would go poof! And I would definitely not run 2 of the four main cabin speakers bridged with the other 2 not.

Wired like I laid out above, the bow speakers will be running @ 100 watts RMS and each main cabin would be running at 75 watts RMS. This is very respectable power for a speaker that's rated for 55 watts RMS/165 peak.

"All speakers are Polk Audio DB651's and both amps are Cadence SQA-4's"

Those polks don't handle hardly any power, so I would urge you not to bridge.

You should just run the new pair in parallel with one set of the cabin speakers and you'll be perfect- 75 watts to the DB651s is absolutely ideal.

Thanks for the replies.

The SQA-4 is only 4 x 60W @ 4 ohms, 4 x 100W @ 2 ohms and 2 x 200W @ 4 ohm bridged.

The Polk Audio DB651's are rated at 60W rms and 180W peak.

So running them in parallel I would only be getting 50 watts to 4 of the speakers, correct?

I see where bridging would be too much but I don't want to take anything away from the cabin speakers. And I already have the second amp.

So maybe just run the 2 bow speakers on 2 of the 4 channels of the 2nd SQA-4 amp?? Can I do that - not use 2 channels?

Or, can I run them bridged and turn the gain way down??

Why not run them of the head unit?

Why not run them off the head unit?

They'll sound better if you run them off of 2 channels instead of bridged- bridging will certainly increase distortion.

Aaron- In theory a head unit can push 35 watts, but in reality they only put out 15-20. This is actually more than enough if you don't crank your music. But generally if you have multiple amps you probably crank your music occasionally and then you'll have a weak link in the chain, which will sound like crap when you turn it up to 11.

bow and midship -ran in series for 8 ohm load
rears on their own channel. i find that i like no bow speakers so people can get to a more relaxing spot. not everyone wants to rock all the time.

882001 - I agree with having a "quiet spot".

That is another reason why I was trying to wire these up to their own amp. I could turn the gains down or pull the RCA's if I need to temporarily turn them off.

FJK, if you put them on their own amp, just add a switch to the remote wire from the head unit to the amp. Then you can just flip a switch to cut the amp off....quick and easy.

just run a rca volume knob on the front
. and wire the midship and back together in series and the fronts on there own channel.

Off the head unit??? hope you are kidding...

Option 1: Just use one amp parallel the 4 in boats to the rear channels and run the bow off the front channels

Option 2: As you described front amp bridged to the fronts, rears all on their own channels. Don't push those bow speakers.

In either configuration set the crossovers in highpass at 100hz. The problem with Polks is the low tweet crossover point. An extreme but viable solution would be to change the cap on the tweet XO to a higher value. Raising it from 2500 to 4000hz would double the power handling of the tweeter. Whatever the value of the existing capacitor is, divide by 2 and solder that one in series.

"882001 - I agree with having a "quiet spot".

That is another reason why I was trying to wire these up to their own amp. I could turn the gains down or pull the RCA's if I need to temporarily turn them off."

Does you head unit not have front and rear RCA outputs and a fade knob? Run the "Front" RCA's to the "Amp1" input, where the 2 bow speakers will be wired, then run the "Rear" RCA's to the "Amp2" input where the 4 main-cabin speakers will be wired. When you want quite time in the bow, roll the fade to rear!

TigeMike, My tower speakers are on the rear RCA's.

Mikeski!!! Can you go into a little more detail about adding the new cap?

What do you mean by the XO?

I have 2 "things" on the back of the speaker now that look like caps. Not sure which is for the tweeter.

Out of the 8 Polk Audio speakers I have, I had to re-solder at least 4 of them back on because they had worked loose or broke wires from when they were brand new.

One of them says 0.35 mH and looks like it has a winding on it (so it may not be a cap). I have no idea what the other is, it doesn't have any markings.

Would I be able to get the cap I need from Radio Shack?

Does this just double the power handling capacity of the tweeter?

What about the driver? And the overall power requirements?

Does it affect the sound quality?

Thanks

Sell the unneeded 4 chnl and apply it towards an EQ. This will give the ability to fade/control volume to tower, rear, and front.

TigeMike, I already have an Clarion EQS746. How would an EQ fade 3 - front, rear and tower. (rear is my tower)?

Also, as I mentioned, I don't want to take anything away from the existing cabin speakers. If I ran 4 speakers off of 2-channels I would only be getting 50 watts to each speaker (not 75).

What would be the problem with running the bow speakers off of the 2nd amp - even in bridged mode? I can turn the gain down?

And, I like Joe's idea of a switch to kill the power on the front amp if I need to.

I'm not extremely familiar with the Clarion, but some EQ's have volume controls for each RCA output, such as front, rear, and sub.

Although running 2 speakers in parallel @ 2 ohm does divide the total watts output to each speaker, you are doubling the speaker surface area in the main cabin by adding that 2nd pair. In your case, @ 2ohms, the 4 main cabin speakers will only be getting 10 less watts then if they were on their own chnl @ 4ohm. IMO, that 10 extra watts will not be noticeable. This is a very common setup.

There is no problem with just using 2 chnls of a 4 chnl amp and running the bows of only half the 2nd amp. It just means one more amp to mount, added power draw, more power cable, etc. But again, no reason you cant do it, but it's just my opinion that it's not needed.

I would not bridge these, 200 watts, IMO, is just too much. not to mention the added current draw of bridged v's stereo mode.

Gain dials are not volume controls. They are intended to set it and forget it. Using a simple on/off switch in series of the remote turn-on wire for that amp is the best method for turning off a single amp.

The Clarion EQ does have front, rear and sub - but that still doesn't allow me to have front, rear, tower and sub. I haven't seen any EQ's that will do that.

I think am I going to go ahead and use the 4th amp to run the bow speakers and leave the cabins as they are. I will probably add the switch to the remote turn wire to control that one amp.

I am curious to see what Mikeski has in mind with the caps. That might determine if I bridge the bow speakers or not.

you'd be trading sound quality for extra power handling if you increased the crossover point.

yeah, nix the XO mod idea. David sent me a message, they are a 2nd order filter, not a first order so it has a cap and coil. You would need to change both, probably more trouble than it's worth.

OK, thanks Mikeski and David. I'll leave that alone.

Now - to Bridge or not to bridge....

I have had these speakers wired in a bridge mode before, just to try them out. I thought there was definite improvement over having them wired to just one channel.

But, if I blow them they won't sound good at all....

Oh, and if I was going to bride one pair - should it be the bow speakers?

I do realize if it wasn't I would lose my ability to remotely turn off those speakers.

(Message edited by ship_of_fools on December 11, 2009)

Final Answer:

Pull amp 2 and put in the attic as a spare. Wire it per Option 1 in my earlier post (same as what TigeMike has recommended). If you want to turn the bow speakers down just a PAC LC-1 or Schosche line level control inline to the RCA's to the front channel of the amp. This is exactly how my boat speakers have been wired since 2006. My amp is a bit more powerful than yours. The MMC's lasted from 2005-2008, I have one summer on the db651 (not db651s, those are shallow, but I assume your "s" is just for plural, not the actual part number).

OK - Thanks for all the input.

Yes, the speakers are db651 and not the shallows - so the "s" was just for plural.