Trimotion setup

I have lived in Lawrence, KS for about 11 years so ML's have always been intriguing. I listened to lots of speakers, but the Motion 12"s were on my favorites list. I quit thinking about them because I thought they were out of my price range...until they went on sale! I picked them up from Kief's (high end audio/video retail store in Lawrence) for a great price. 5 months later I upgraded my center to a Motion 8 for movies. The music imaging on 2 channels is incredible and the brightness of the Motion 8 makes movies come alive. All this being said, I still feel like something is missing. I haven't had a chance to read many forums about this, so if is redundant, I apologize. My receiver is a Yamaha Aventage 700 that uses YPAO to set the perimeters. I recalibrate it often because I'm trying to get it to the sound that I want. I know they have the potential because when I experienced them in the store, they were outstanding. I auditioned them with a Yamaha A1000 something. I don't remember the exact model number. My room is about 12'w x 25'L with one open wall to the right. My chairs sit 12' from the speakers.
I will do some more research on this website and read some more threads, but would someone also give me a bit of advise? I have more thoughts, but I don't want to bias anyone responding. Thanks.

You don't list what you think you are missing in the sound. Is the bass weak? Or booming? Imaging? Soundstaging? What is it you think you are missing? Without knowing more, I would simply offer this. Your weak link is probably the receiver. The power output for that receiver is pitiful. ML's need a lot of clean power to sound their best. Something like 200 wpc at 8ohms, and doubling to 400 wpc at 4 ohms, at a minimum. You may also want to read up on acoustic treatments, as your room may have acoustic issues that prevent you from getting the most out of your speakers.

I echo Rich's response. You may also want to invest in a ML subwoofer. Audio Advisor has got them on sale now. They have been slashed to below $1K normally selling for $1,600. This sub will mate well with your Motions providing detailed, accurate bass foundation.

I have an Onkyo 10" SK-150 subwoofer that does a pretty good job at supporting my lows, but I also don't really have anything to compare it to. I feel like I've been missing some of the precision that I heard when I auditioned the Motion 12's. I too suspected that my receiver was not doing my ML's any justice. How do people feel about external amps? What if I kept the receiver, and got an amp for my front 3 channels? Or does it make more sense to buy a new receiver?

I would suggest considering a separate stereo amp for the front L&R channels and powering the center and surrounds with the receiver. If you want to get the most out of your stereo music listening, you could also consider a good preamp with a home theater pass-through. Acoustic treatments behind the speakers to absorb some of the back wave of your speakers can also help tremendously with clarity and precision.