I would like to take 2 old polk speakers I have (2-way), and put both woofers and one tweeter into a box of my making. Of course, there's only one channel output, so I'm wondering how to avoid impedance problems when I merge the two speakers. Is it going to be easier to use both tweeters? Do I attach both sets to one crossover in parallel, serial/parallel, or what?

The amp I have (a teac with tripath amp chips) is good sounding, but anemic in some ways. The speakers I was using are inefficient, and 6ohm, and this amp just doesn't handle them well. I've read that they need a high current amp, and I've found this to be true. At any rate, I don't want to reduce the impedance of the "center channel", and I probably don't want to double it, either. Any ideas?

I've already replaced the front R and L speakers with some other polks I have, which took care of the problems in those channels, and would just like to make the center channel more closely match. I may not use rear speakers for 5.1, since I'm just about out of speakers. I can't buy anything, so keep that in mind. kj.

While I see what you're trying to do, have you considered just building a new box (sounds like dimensions are one concern) and putting the guts from one speaker into it? The woofers from any two-way bookshelf speaker are already going to have a lower frequency response than anything in a standard "center channel". I don't think having two of them would make much difference. Of course, if dimensions don't matter, you could just use one of the speakers as-is in the center. Then, you will have also preserved the acoustical integrity of the original box designers. I'm just not sure what you're trying to gain, or if it's worth it.

Then again, if you're just looking for a project, good luck!

FWIW, I used a Boston A40V (bookshelf speaker) as a center for a number of years and it sounded pretty good, considering.

In parallel with a 4-(phorum chokes on "ohm" sign) "dummy load" resistor?

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New forum user map 8/2015: [www.zeemaps.com]

The tweeters aren't going to change the load of the box enough to factor in. Just factor your woofers
and determine how you are going to wire them. That will constitute the impedance of the box (and this is
not factoring in the load of the box, crossovers, etc., just general guidelines).

You want exact answers, ask Dick Moore - he worked for Paul Klipsch for years as an engineer.

btw... personally, I'd never use a full range speaker for the task. You need to realize what makes up
the content of the center channel - and you'll see why they are of limited bandwidth.

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Tweeters are usually more efficient than woofers, so I hope when you open up the speakers that you find some resistors in series or series/parallel with the tweeter. This is important, because putting two woofers together will increase their output level by 3dB -- twice the acoustic power. This means the single tweeter's output will need to be 3dB higher in order to match level, which means removing or adjusting level padding resistor(s). The crossover network will probably be OK for the tweeter; use the woofer network only from one of the crossovers for the second woofer. For more information, you'll need a book like "The Loudspeaker Designer's Cookbook" or something similar.

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What it is, man, a low-down and funky feelin'

Try just one and set the center speaker on your receiver to small and that will roll off the bass. Lots of basic info at Parts Express.
[www.parts-express.com]

I don't want to use a single speaker, as is, because they're really ugly. More importantly, it won't fit into the space.

Also, my current center is two 4" woofer/mid and one tweeter, which seems somewhat common, so that's where I am getting the configuration. The polks I'm repurposing are just 5.25 in woofers, so I don't think excessive bass is a huge prob. I was going for more mids than the original speaker, so I thought two mid/woofers, half the tweeters, in a sealed (rather than the existing ported), would probably do that.

So, hooking the mid/woofers up serial would double the impedance, right? That isn't likely to kill the amp, is it? I know dropping the impedance would, and of course, I think that's the prob I have now.

What I really need is a nice amp, so I can use my nice speakers, but I don't see having extra money for quite some time, so I have to make do. I also have plenty of time to futz with it, so what the heck. I care more about quality of sound when listening to music, and not so much with home theater, so I think I can get something that works, just so I don't blow my amp up. Thanks, kj.

Hook the woofers in series with the positive of the first connected to the negative of the second.

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What it is, man, a low-down and funky feelin'

Gotcha. Thanks Dick. I'll post a followup if it works out. kj.