Speaker Polarity

mufsoman · November 2013

Today I was testing the polarity of my front sound stage wiring to confirm that all was right with the hook ups, and found something interesting. I used a small battery to actuate the drivers on my Rti12's. When the woofers (bottom three drivers) were actuated with the battery polarity wired to the terminal posts the same, positive to positive and negative to negative, the drivers inverted vs. pushing out. When I did the same thing to my CsiA6 center channel, the two large drivers pushed out instead. Shouldn't all the drivers move the same way with the same polarity??? If the drivers are moving opposite directions, isn't there cancellation of sound waves? Is there something not right with the internal wiring in my speakers? Thanks

[Deleted User] · November 2013

The woofer cones should move outward when a DC pulse s applied to the corresponding terminals. Are you aware of any service work that might have been done to your speakers?
Regards, Ken

mufsoman · November 2013

No service done. My Rti12's and CsiA6 are all refurbished purchased from the Polk online store.

So are both of my Rti12's internally wired with reverse polarity? What are the odds of getting two with that situation?

F1nut · November 2013

Check that the binding post nuts are not reversed.

mhardy6647 · November 2013

The "in-phase"/"out of phase" tests on test discs (I think the one I have was from Stereophile) are very handy in assessing phase-related issues. FM interstation noise in mono can also be useful (in a pinch).

While it is easy to check woofer phase (polarity) with a battery, it won't always work with a loudspeaker system; DC may not make it through the loudspeaker's crossover.

mufsoman · November 2013

I confirmed my original findings last night. As per mhardy's comments above, the three bass drivers move fine with the battery test, but the upper/mid range do not. So not sure if the upper/mid is reverse polarity also or not. When I attach the battery to the upper/mid, I just get a click from the tweeter, but no mid cone movement.

I also confirmed that the binding post nuts are in the correct location, at least vs. other Polk speakers I own; red/positive on the right when in back of the speaker looking at the binding posts.

I have been struggling with lack of bass from the Rti12's since I first got them, but could not find any assignable cause. Looks like I have finally stumbled onto something. Unfortunately, after the warranty has expired.....

Not familar with the phase test disc, so any other suggestions for testing the upper/mid? If I remove the crossover board, is there something particular I could look for?

I did try switching the polarity of the speaker cables for the bass. Bass did seem to get better, but I need to confirm the upper/mid. Thoughts?

mufsoman · November 2013

In case anyone is following this post, I will close this out with the the resolution.....

First off, Polk customer service is awesome. Great help from Ken & Kim. You guys are great!

As to the polarity concerns, as it turns out the Rti12's are designed such that the three bass drivers are wired in reverse polarity from the tweeter and mids. This is to ensure proper phase of the sound waves from all three sets of drivers. All drivers in the CsiA6 are wired in standard polarity. So bottom line is that my speakers are correctly wired. I took Kim's recommendation of setting the phase of my subs to 180 instead of 0, so the phase of the subs match the phase of the bass drivers in the Rti12's. Really made a difference with how much bass response I now get.

Still don't get much bass response in 2 channel though, when the subs are turned off and the Rti12's are set to "Large". I'll have to keep tinkering with that.....

Face · November 2013

Most designs call for the woofers to be wired +, then work up front there...very odd.

Speaker Polarity

Comments