Tower speakers: single 6.5" driver vs. dual 5 1/4" drivers

[jackbomb]

I'm currently running a 5.1 speaker system off a Pioneer 7.1 amp. Four bookshelf speakers, a center speaker, and a powered sub. I'd like to take advantage of an incredible Grand Opening sale and upgrade to 7.1 audio this week.

I'd like to bring the front bookshelf speakers to the middle of the room and use them as side surrounds, then put a brand new pair of tower speakers up front. I've narrowed it down to these two Polk Audio sets.

Each speaker in this set has a single 6.5" woofer and a 3/4" tweeter:
http://www2.visions.ca/catalogue/category/Details.aspx?categoryId=159&productId=2383&menuId=368&parentId1=155&parentId2=''&parentId3=''&menuLevel=2

Each speaker in this set has two 5 1/4" woofers and a 1" tweeter.
http://www2.visions.ca/catalogue/category/Details.aspx?categoryId=159&productId=3112&menuId=368&parentId1=155&parentId2=''&parentId3=''&menuLevel=2

I'm actually more concerned about CD audio than movies, since I like to listen to CDs in their "native" 2.1 mode with no 5.1/7.1 upconversion. These speakers will be accompanied by a largish 12" subwoofer. Keeping that in mind, you guys think a single 6.5" driver + 3/4" tweeter would sound better balanced than two 5 1/4" drivers and a 1" tweeter? Thanks

[Captain Ned]

Go with the TSi300s. The D'Appolito configuration tends to produce much more coherent soundstages with better off-axis imaging (i.e. a bigger "sweet spot"). They're also not bass-reflex, for which I have a personal dislike. Since you've got a powered sub, the loss of low-frequency efficiency in an acoustic suspension speaker like the TSi300 will largely be mitigated by the speakers never seeing all the LF content.

If the powered sub has a variable crossover frequency, once you've got the system up and running twiddle with that with an eye to bringing the crossover frequency as low as possible without losing the midbass from the main speakers.

[ludi]

The only thing to recommend against a bass reflex configuration is that a badly designed unit will tend to be boomy or muddy, which doesn't stop the low-rent builders from trying, as the increased bass efficiency reduces the box size and power requirements.

That said, I would also prefer the TSI300. Two 5.25 inch drivers have much more surface area than a single 6.5 incher (almost as much as an 8 inch driver, actually). The midbass response should be better, and the reduced bass efficiency of the sealed box is mitigated by the higher rated efficiency of the system and the broader frequency response if offers. 35Hz on the low end rolloff should allow these to blend very nicely with the subwoofer, and you may find the subwoofer crossover can be set as low as 40-45Hz.

[sluggo]

To clarify, both of these designs are ported. The TS product has it's port in the back, however.

I'd go with the TS as well. You'll get better definition and control in the bass, as a 6.5" ported speaker at this price range is going to be peaky in the low end. And if it's important to you, Polk's cherry veneer (which is not available in the less expensive speaker) is done very well.

[jackbomb]

Thanks a million for the sound advice! That was exactly the kind of info I needed.

TSi300 it'll be.