Setting speakers to Large or Small?

[AZHT]

What should speakers be set to? When listening to HT Large seems to sound better to me. For 2 channel stereo, Direct 2 channel & 5 channel stereo CD listening Small sounds best. But for listening to AM/FM radio Large sounds better. Better as in more overall bass response. Anyone have any suggestions how to set this?
Here's what I'm running:
Denon AVR-2800
Denon 910 DVD - for DVD and CDs
Fronts: Paradigm 9seMkII
Center: Paradigm CC-350
Surrounds: Paradigm ADP-350
Subwoofer: Klipsch KSW-12

[Kursun]

I believe,
* If you have a receiver with selectable crossover frequencies you should choose the lowest crossover frequency within limits of your main, center and surround speakers.
* You should always select "small" speakers on the receiver's setup.

Such a setup will allow the subwoofer do its best at true sub frequencies as its operating range will get narrower. Its power handling capacity won't be wasted by frequencies that can be handled by other speakers. It will handle the chest (and floor) vibrating frequencies with better authority.

As for "small/large" speaker option, if you select "small", the sub-sonic frequencies will be filtered from your main, center and surround speakers. Most loudspeakers today are vented designs and such designs don't like receiving sub-sonic frequencies. Below their resonance frequency, speakers in vented enclosures get decoupled from the port and their cones start acting like they are working in free-air (less damping and control from the enclosure). If you listen to material with lots of sub-bass you will experience this condition.

On the other hand, final setup adjustments, especially if you have no option of selecting the crossover frequency (other than 80 Hz.), will always depend on the equipment,room acoustics and your taste.