2.5-way centers (and Polk CSi20 vs CSi30)



<font color='#000000'>In an audioholics-FAQ, Gene DellaSala says,
<table border="0" align="center" width="95%" cellpadding="0" cellspacing="0"><tr><td>Quote </td></tr><tr><td id="QUOTE">2 1/2 way systems have recently entered the hi-fi market of loudspeaker design. This design employs 2 bass/mid-bass drivers usually identical in design and size and a tweeter. Usually the bottom woofer is crossed over to produce bass frequencies below 200Hz and the top woofer is crossed over to produce midrange frequencies between 200Hz - 4KHz. The interesting thing about this design is that although the two woofers are crossed over at different frequencies, they acoustically couple to synergistically enhance overall system bass response.</td></tr></table>
   My practical interest in this is that I'm debating between two Polk Audio center channel speakers.  According to specs from Circuit City, the CSi20 has one driver (5.25&quot; Dynamic Balance) and a .75&quot; Dome Tweeter, while the CSi30 has two 5&quot; drivers (5.25&quot; Dynamic Balance) and a 1.00&quot; tweeter (Dynamic Balance Dome).

   I had assumed that both drivers of the CSi30 would be doing the same thing, except twice as much, but Gene's &quot;2.5&quot; explanation makes more sense.  Is this (with each midrange handling a different part of the spectrum) the way Polk uses these?
My practical question is: What difference does this make in the actual sound qualities of the i20 and i30?  If they use the &quot;2.5&quot; crossovers, will the difference be more than just the amount of sound?
   If any of you have listened to the i20 and i30, how do you think they compare?  What would be the advantages of the i30?  { my audio context: I just bought an Onkyo TX-SR501 receiver with 6.1, will use 3-way 8&quot; speakers (my pair of old Sony SS-MB215, and two new equivalents, Sony SS-MB350H) for the front and rear L-and-R, am not sure what I'll use for the rear-center. Currently I'm in a small room, but eventually they'll probably be in a larger room, and I listen to music much more than movies. }

Thanks, in advance, for any help you're able to provide.


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