I spent last night rearranging my set up and I discovered / learned a few things in the process.
The first thing I did was to pull the Technics receiver out of the mix. There's nothing wrong with it, I just wanted to utilize a three to five speaker front soundstage.
I ran all the cables to my Harman Kardon AVR 340 and then I put it in place on the rack.
I turned on the TV and the HK so I could utilize the On Screen Display (OSD) to set up the levels using my analog SPL meter.
A few things I should mention: First is that I am not running a subwoofer; I live in an apartment and I'm not looking to disturb the whole building with low frequency devastation. Second, Due to the layout of my main room, I am not able to run surround speakers at this time; there's no way to run the wires to the back and I'm missing one wall to mount a speaker plus, the futon is right up against the back wall, so the position for surrounds to be effective isn't there for a variety of reasons.
Back to the new(er) set up - The HK AVR sounds much better with the RC-70 speakers than did the Technics stereo receiver. Honestly, the RC-70s sound very good paired with the HK. I'm running the HK flat, no tone controls engaged (same as the Technics before the HK).
With the stereo mode sounding fabulous, I tried the front three speakers and was immediately aware that something was missing. Same thing for my significant other; she let out a few "ooo's" when hearing details / things in music she hadn't heard before in music with which she was familiar.
Today I got home and went through some of the settings and I discovered what the difference was in the two settings. Not limited to three channel listening, but associated with any mode other than stereo, the receiver cuts the frequencies below 40 Hz off from the speakers. In my humble opinion, this cuts the meat from what makes a set of tower speakers sound so full and rich when listening to the full spectrum of frequencies that they are capable of reproducing.
I don't think that, in a home theater setting, there is any need to go beyond the RC-LCR for your front speakers. The RC-10 speakers are very good, but the RC-LCR will give you the little extra detail from the additional 5.25" driver and the two 2" midrange drivers because the sub (in your system) will pick up all the low notes below 40 - 60 Hz (depending on where you set your crossovers). The RC-70 speakers sound great when they are running full range but, the RC-LCR is perfectly capable with a sub to pick up the slack. I guess what I'm trying to say, if I haven't said it already, is that (in my subjective opinion) the RC-70s are wasted as mains in a HT set up. They will not flourish as they are designed to do when their ability to reproduce a full spectrum is disabled. It's like buying a 300 watt amp and putting a choke on it so it's only capable of 50 watts.
I did run the EZset EQ, but I didn't find the results to be all that much better than my original settings with the analog SPL meter. I will say that I think Audyssey does a much better job with room corrections and calibrations. I have a slimline Marantz NR1402 in my bedroom set that sounds great paired with some Polk Audio RTi6 speakers. I can only imagine how amazing my main set up would be with an Audyssey enabled AVR. That will have to wait, for now, but I will get there eventually.
I connected the RC-10 speakers to the Multiroom / Zone 2 / Surround Back outputs on the HK and they sound good. I will have to run a test tone through them all independently to try to level match them, as the built in test tone generator doesn't run through the Multiroom speakers and the Main FR, FL, Center, Surround L, Surround R, Subwoofer, Surround Back R, Surround Back L. Yes, these are connected to the Surround Back L + R but, when running them in the Multiroom mode, I have to set the volume level independently from all the other speakers. I'm sure there's a way to do it, in fact I may have just figured it out, but it's not super important right now.