I want to run 8 speakers on one ARC 600.4 amp. On the front channel, I want to put two mm651's in the factory speaker location and two in the lower fairing speaker pods. Out back, I want two mm651's in the tour pak and two mm691's in the saddle bag lids. But I don't know if I should run them parallel or in series.


Series = more ohms
Parallel = less ohms


What happens when you put two Polk 2.7 ohm speakers in series and in parallel? Either you get 1.35 ohms or 5.4 ohms? Which is better? I fell that 5.4 would be the safer bet, but it may cut down on the sound. But 1.35 ohms would be too low. The Polk DB series are aggravatingly in the middle and pose an issue when trying to run two speakers on one channel.


Any ideas, comments, or experience with TWO Polk DB speakers on ONE channel?

 

Do u already have the Moto 600.4 in your possession?

Are you hell bent on these Polks. Great speaks, MM651 a better play, but regardless these Polk ohms raise hell on multi-speaker setups.

T

 

If don't have this already there's better options for running 8 speakers on a bike.

 

To add to what my friends Tailwind and BAL have already stated. Anytime you want to run 8 speakers on 1 four channel amp you need 4 ohm speakers. There is never a reason we should be running speakers in series on a bike.

One of the goals on a bike is to get the most bang for the buck. Your speakers in series will not have enough power to hear going 80 mph down the highway. Your optimum set up with 8 speakers is gonna be two 4 channel amps with each speaker on it's own channel.

 

I don't have the ARC amp yet. I did purchase a set of MM691's for $103 and a set of MM651's for $87. So I am stuck with the Fo'Polk's.

What do you mean by this?


It seems as if Polk's are good speakers, just not for multiple speakers.


I am not apposed to running a second amp, but it does get more complicated when stepping to that level. The space requirement and power draw from a second amp is something I wanted to avoid. The charging system would likely need to be upgraded when adding a second amp, correct?


How do you split the signal for two amps? What effect does line level inputs have when using two amps? I am thinking having pre-outs installed by Iron Cross.


Sounds like I may be better off sticking with the four speakers I have now. I can put them in the fairing and in the saddle bag lids. I wanted to put the extra speakers in the lowers and in the tour pak speaker pods. I am going with a removable tour pak.

 

Keep your amps at Class D and you'll be fine. I'm running 2 amps at 1600 watts with no problems, even guys running 3 amps no problem (within reason). Some thing like a 4v2, B54, or D4 wouldn't take up much space. Attached a picture to give you an idea how much space is needed for a B54.

 

If u can return the speaks u bought, the original goal of 8 speakers becomes very realistic with one fairing amp. Not the ARC though.

Let us know, if not I think ur solutions get complicated and expensive.

As Gann mentioned, 4 ohm is the focus!!!

T

 

The Polks are good speakers! Don't need a expensive Arc Moto to run em though. A Cerwin Vega B54 is all you need with the Polks. They sound damn good with that amp.

 

I got this back from Arc Audio...


"Hi Shimaze,

You’re right that the safe solution is to series wire the speakers. The Good news is that the MOTO 600.4 has switches to help compensate for this. On the side right next to the speaker output plugs are 2 switches the select 4 ohm or 2 ohm output. I don’t see any problem with the amp producing 125 watts per channel into a 5.4 Ohm load.

When set into the 2 Ohm load the amp will probably run the 1.35 ohm load but this is going to be harder on the speakers and on the bikes charging system. 5.4 Ohm is your best bet."

Regards,

Brad Ott
ARC Audio
Technical Support
209-543-8706

 

His numbers are correct. No problem there. What you're looking for is loud and clear going down the HWY at 80 mph. Not gonna happen with the arc amp and the Polk speakers wired in series at 5.4 ohms. If you trust what the Arc tech is telling you. Go for it! But I almost guarantee you'll be right back to the drawing board.

I've had extensive experience with the Polks and for them to sound like they are supposed to sound you need about 150 watts per speaker @ 2.7 ohms. The guy with the Cerwin Vega B54 will blow that Arc set up in series away. Your money Bro. But that's my .02