longwinded Bi-amp question

bailbomb
bailbomb Posts: 1
edited January 2010 in DIY, Mods & Tweaks
First off, Hi to all my fellow Club Polk members. Kinda cool a product comes with its own forums. Hopefully I can get some nagging questions answered by picking your brains.
Bi-amping. I am the proud owner of 2 RTi12s and a CSi5. Yea discontinued models but got them at a great price and for some reason the salesman at Frys threw in a new sub to boot . Free Sub sure! I like free.
Anyway after I bought the speakers, I did some research about them and almost all reviewers loved them but commented on the fact they are power hungry and my sony AV receiver might not have the ooph to really get the best sound out of them. Back in the early to mid nineties my mains were a pair of OHM Walshs with a Infinity CS. One day I came across a orphaned pair of JBL THX certified Subs (unpowered) for 100 bucks apiece and snatched them up. Did my research and picked up a crossover that I set at 80hz. So used the eq out to feed the crossover and ran the highs back into the HK receiver and the lows to a Yamaha M45 amp I had sitting around for the subs. This configuration in my mind gave the HK some breathing room since it no longer had to output 80hz and below.
So fast forward to today. I have been digging through the forums looking to see if someone else had already asked the questions I was going to ask and I found one thread where someone was asking about a external crossover and a Polk tech replied run the 2 amps in and let the internal crossover in the speaker do the work or something to that effect. So this sounds to me since there is no external crossover, both amps will be sent full range signals. So both amps are wasting energy outputting signals that will be filtered out by the crossovers.
I still have the M45 powering the 2 JBL subs but most of the time they are turned off because it is too much for the apartment. The Free 111 is currently plugged into the LFE output and does a very good job without simulating a earth quake. I would like to use the M45 to power the low end of the RTi12s so I can get better bass at the moderate listening levels I normally use and like in the past free up the receiver from the duties of reproducing the lows to give it more headroom. So I’m thinking if I set the amp to “small” for the mains and feed that to the high side, Im freeing up headroom. Then ill have to see if I can find a fullrange output on the back of the AVR to feed into the M45 for the low end or feed the LFE into the M45.
So as in the past there were THX standards, are there standards for Dolby Digital amps? When a speaker setting is set to “small” what frequencies are filtered. Does the frequency range of the LFE change when a speaker setting is set to small? What is the crossover frequency inside the RSi12 for the low end?
Sorry longwinded. And thanks in advance. PS: the OHMs are still on duty as my surround speakers lol.