Can I Put Line Output Speakers in Parallel on Fusion MS-RA70NSX?

scooper321

Well-Known Member
Jul 4, 2015
1,849
Baltimore, MD
Boat Info
2003 Sea Ray 400DB
Engines
Twin Cummins 6CTA-8.3
Replacing the Clarion XMD1 head unit on my 400 sedan bridge with a Fusion MS-RA70NSX head unit. The boat has 8 speakers and a sub woofer. 4speakers outside, with the sub. Four more inside. The Fusion has two zones. I want Zone 1to be outside, Zone 2 to be inside. The Zone 1 RCA outputs from the Fision feed an amp, which drives my outside speakers (2 connected in parallel on both L and R) and the subwoofer. Great. Zone 1 is designed.

I want Zone 2 to be driven off the speaker level (not RCA) outputs of the Fusion. There are 4 Zone 1 and 4 Zone 2 speaker level outputs (L+, L-, R+ and R-).

My question is this: can I connect the two L inside speakers in parallel to the Fusion’s Zone 2 Left speaker level outputs (and drive them directly from the RA70N)? And the two R speakers in parallel to Zone 2’s right speaker level outputs? There’s nothing in the literature saying whether the Fusion can support 2ohm output impedances (which is what I’ll have with two 4-ohm speakers in parallel).

My alternative is to use the Zone 2 RCA jacks and go to an additional 2 channel amp for the indoor speakers. But I don’t want to add an amp for indoor speakers if I don’t have to.
 
It's kind of hard to follow but I had a similar (I think) challenge when installing my Fusion head unit. I wanted to be able to separate by zone the cabin speakers from the cockpit speakers. Unfortunately, I couldn't get there with the RA70N without a significant amount of additional work on the install. If I recall correctly the zone 1 and zone 2 are split on the speaker outputs and can't be changed.

In order to be able to have kids sleeping with music playing outside I had to wire my forward cabin speakers to the same zone as the amps for the cockpit. This way I can turn down zone 2 (the speaker level speakers closest to the kids room) while still having normal volume on zone 1. It works fine but is not ideal.

Had I added one more amp to the setup we would have had full flexibility on the zones. But I really had no desire to add a new amp to the interior speakers on my rig.

EDIT - Sheesh....I didn't even read your full post. The parallel wiring would potentially solve the issue I have. Obviously you're in a similar boat (ha) that I was in. Though I solved it without going 2ohm :)
 
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Wire them in series not in parallel if you are worried about the combined impedance being too low in parallel. That's what I did with my cockpit/bridge speakers when I replaced the 4 ohm speakers with 2.7 ohm Polk speakers.
 
Actually, after reading your reply, it sounds like you understood what I wrote exactly! Lol. The old Clarion appears to have been wired exactly as you described - with the foreword stateroom speakers on the same (front) zone as the outside speakers. But that means when turning up volume outside, anyone in that stateroom gets blasted. Not ideal. I just don’t know if the head unit can handle 2 ohm loads on the speaker lines or not. I suppose I can try it and see, but I’d prefer to know it’s ok first. That’s the simple solution. Like you, I don’t want to add an amp if I don’t have to, just for indoor speakers.
 
Wire them in series not in parallel if you are worried about the combined impedance being too low in parallel. That's what I did with my cockpit/bridge speakers when I replaced the 4 ohm speakers with 2.7 ohm Polk speakers.

That’s a thought. But it’s the same dilemma, just a different impedance value. Nowhere in the Fusion literature does it say the head unit can successfully and safely drive an 8 ohm load on the speaker outputs! I have an email in to Fusion Support on this issue. I may call them today, too.
 
So I called Fusion this morning. They said NOT to run 4 ohm speakers in parallel (for a 2 ohm load). Doing so would (and I quote) "let the magic white smoke out" of the head unit. They also recommended NOT running them in series (as an 8-ohm load), with the same explanation. I'm a little skeptical of that, but this is what tech support said. So my options are two:

1) change the inside speakers to 8 ohm speakers and run each channel (L and R) in a parallel config to get a 4 ohm load, OR
2) add an amp to drive the inside speakers (taking the zone 2 RCA outputs from the head unit, to the amp, and connecting the speakers to the outputs of the amp).

I'm leaning towards #2, as it's a bit lower cost. And, I think, a bit lower effort. I'll have to re-read some posts in the 40 sedan bridge thread about how to route power to an additional amp. A couple folks there have done it.



'
 
So I called Fusion this morning. They said NOT to run 4 ohm speakers in parallel (for a 2 ohm load). Doing so would (and I quote) "let the magic white smoke out" of the head unit. They also recommended NOT running them in series (as an 8-ohm load), with the same explanation. I'm a little skeptical of that, but this is what tech support said. So my options are two:

1) change the inside speakers to 8 ohm speakers and run each channel (L and R) in a parallel config to get a 4 ohm load, OR
2) add an amp to drive the inside speakers (taking the zone 2 RCA outputs from the head unit, to the amp, and connecting the speakers to the outputs of the amp).

I'm leaning towards #2, as it's a bit lower cost. And, I think, a bit lower effort. I'll have to re-read some posts in the 40 sedan bridge thread about how to route power to an additional amp. A couple folks there have done it.

'

Cool. Sounds like the "right" way to do it for sure. Maybe someday I'll grab a cheapo 2 channel amp and correct my setup as well. But that has to be somewhere near the bottom of my list of boat projects at the moment.
 
If you dont mind me asking you guys, how do you like the fusion head unit? I am considering upgrading the OEM Clarion and removing the CD changer (i dont actually own any CD's anymore) and thinking of something to do with the HOLE?
My 420 DA has selectable rocker switches just inside the salon door, but I was considering the fusion so that I could do just what you proposed, tune the volume of the cabin separately from the cockpit?
Thanks guys
chris
 

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