Setting an AVR for Large or Small Speakers

I have an Onkyo TX-SR805 A/V receiver driving Paradigm Monitor 11s (front L/R), CC-390 (center), Mini monitors (surround L/R), and PW-2100 powered sub. I found a page on the Audyssey website that recommends setting the speakers to "small" after running the auto setup and letting the sub do the so-called heavy lifting. But the Paradigm dealer and everyone I have ever talked to about this says you should always set the speakers to "large" regardless of their actual size/low-frequency response.
What do you think about setting full-range speakers to small as Audyssey recommends? The SR805 does not have a "Large/Small" setting; it lets you specify each speaker as "full-range" or set a crossover frequency between 40 and 200Hz. Where should I set the crossover for the speakers? If the speaker cutoff is (for example) 80Hz, should the sub lowpass be set to the same frequency? If I set the Monitor 11s to 80Hz, does that mean information below 80 Hz will be sent to the sub? Does the amp still send full power to the speaker even though it is set to small?
Kevin Hoeft

I totally disagree with anyone who says you should always set the speakers to "large" regardless of their actual size/low-frequency response—which means I agree with Audyssey that you should set the speakers to "small" when using a subwoofer, even if the main speakers are full-range. Why? First of all, if the speakers are not full-range, there's no point in trying to make them reproduce low frequencies.
Even so-called full-range speakers rarely reach as low as true subwoofers. In your case, the Monitor 11 specifies a low-frequency extension (the frequency that measures -3dB from the nominal level in a typical room) at 30Hz, which is pretty low, but not as low as the PW-2100, which specifies a low-frequency extension of 23Hz. I was unable to find the CC-390 on the Paradigm website, but the CC-490's low-frequency extension is specified at 43Hz, and the Mini Monitor's low-frequency extension is 42Hz. The specified on-axis frequency response (±2dB) of the Monitor 11 goes down to 42Hz, while the CC-490 goes down to 65Hz and the Mini Monitor goes down to 75Hz.
Then there's the issue of speaker location—the best positions for low-frequency drivers in a room are often not the same as the best positions for the midrange and high-frequency drivers. Redirecting all the low frequencies in a soundtrack to one or more subwoofers lets you optimize the bass performance of the room by placing the sub(s) independently of the main speakers. And because low frequencies are not directional—that is, you can't perceive the direction from which they emanate—they needn't come from the main speakers for the sake of imaging.
You're right that the TX-SR805 does not have "large" and "small" speaker settings per se. Instead, it lets you specify each speaker as "full-range" (which is equivalent to "large") or set a crossover frequency (which is equivalent to "small"). Unlike most AVRs, this one lets you set a different crossover frequency for each speaker individually, but I generally recommend setting it the same for all the main speakers as well as the subwoofer lowpass frequency.
The THX specification for crossover frequency is 80Hz, so that's where I'd set the speakers and subwoofer lowpass. You might want to try different settings just to see if they sound better—in particular, setting it a bit lower for the front L/R than the center and surrounds might work in your case, since the Monitor 11 goes lower than the others—but 80Hz is a good starting point.

To answer your last two questions, information below the crossover frequency is redirected from the main channels to the subwoofer. And the amp still sends full power to the speakers even though they are set to "small."by scott wilkinson