Magnepan, Best midrange?

I mention Magnepans all the time. The 3.7i is a best buy loudspeaker for sure. Ultimate midrange? No. That is the domain of ESLs. 

dynamiclinearity, you are close but not quite. LINE sources fall off at 6 dB/oct vs 3 dB/oct. The 3.7i's switch to point source behavior from about 250 hz and under. So, from the lower midrange down they are point sources. This is why Maggies tend to get bright as you move away from them. In order to radiate as a line source a speaker has to taller than the longest wavelength it is to reproduce. 20 hz is 32 feet. Fortunately physics comes to the rescue. If both ends of the line source end at boundaries Like the floor and the ceiling the line source effectively goes on into infinity or performs as such down to zero Hz. This is the reason for 8 and 9 foot speakers, the most common ceiling heights. Magneplanar had discussed making 8 foot 20.7s but the marketing guys talked them out of it. They said it would never sell. The people who buy 20,7s are seriously interested in sound. Having superior bass performance would have been an EASY sell. It is the 7 footers that would have been languishing. Go figure. 

To mention Tektons and Magnepans in the same breath is a serious insult to the Magneplanar corporation.

twodoplphins, you are not the only person here with that opinion. As for 99.97% perfect? Maybe 99.95%. Really, it depends on how much you really cherish sub bass and how loud you want to go. If you want to crack the foundation with Nine Inch Nails then you will have to add subwoofers which IMHO should be added anyway to get the last word in perfection out of them. On their own I would say 90% perfect. With the right subwoofer system, 100% perfect. I have never heard another speaker perform at this level. Many would say, "Well of course! You own them." But, I would respond by saying that is why I bought them. 
As for Tube amplifiers, there are many who have said the ultimate amp for driving SLs is the Atma-Sphere MA2. I hope to hear that combo at some point. Other tube amps? I am not so sure. I do know that high powered SS amps can do an excellent job. The JC 1's are a very popular amp with the SLs which are what I am using currently. As Ralph has pointed out on numerous occasions Stats have a rising impedance in the bass and by 20 Hz can be up to 30 ohms which robs power from SS amps so you really need a big bruiser to start with. This is not a problem for the Atma- Sphere amps which put out the same power regardless of impedance. In relative terms the 220 watt MA2 is more equivalent to a 600 watt SS amp driving SLs.

hshifi, the MiniDSP is a much better crossover than the CR1. It is not that the CR1 is bad, it is now outdated outdated technology. Subs have to be placed differently than the main speaker but the have to match the main speakers in time and phase. You can only perform these corrections in digital. You can also program any crossover point at any order. All planar speakers require subwoofers. They are simply overwhelmed by the physics of the situation. 
clearthinker, you and I are certainly of the same mind when it comes to Tektons. Rock and roll. However, I am not a huge ML fan. They are for people who never listen above 80 dB. As the volume increase the curved diaphragm becomes non-linear and distortion sets in. They start to sound stressed. They also have to cross over to dynamic drivers at a higher frequency, 250 Hz I believe so you wind up with disparate sound projection, line source above 300 Hz or so and point source below. As you move away from the speaker it gets brighter. I think Roger Sanders makes the best Hybrid speaker from an absolute performance perspective but he is of the opinion that a speaker only images at one position and that is all that matters. Everywhere else does not matter. I think this is a better compromise to make than curving the panel to increase dispersion but, I made that compromise for decades, head locked in a vise. I am super glad I do not have to make that compromise any more. Sound Labs has the right solution, small flat panels angled to form a continuous 45 degree array. They are better at projecting the third dimension than any other speaker I have heard and only two others ever got close, Apogee Divas driven by Krell amps and Dick Sequerra Pyramid Metronomes powered by Threshold amps. This is of course "in my experience" which was pretty comprehensive.... 40 years ago. It is impossible today to keep up with everything. 

kennyc, I would go with the 20.7s and subwoofers.

@douglas_schroeder , When you listen to speakers "in your own room" you are in effect listening to "your room."  The Aspen Acoustics speakers are overwhelmed by their tweeters. The tweeter is line source but everything else is point source. They radiate differently line sources projecting much better. As you move away from the speakers they get brighter. This creates a sound signature that many audiophiles love. I had a friend way back in Miami who stuck these huge RTR electrostatic tweeters on top of a box speaker (can't remember which one) and he kept them turned way up. He thought it sounded great. I couldn't keep my eyes from crossing. 
I have not listened to the Kings, do not know them at all. But I do know ESLs intimately otherwise having lived and worked on them for decades.
They can be so neutral they become boring for people who have not been able to take advantage of them to the fullest. It is always a bad idea to change horses in the middle of the stream. Line sources and point sources have such disparate radiation patterns and projection that it is always a bad idea to go from one to the other, particularly in the middle of the audio range. If the Little Sound Labs have one big problem this is it. They switch from line source to point source behavior at about 350 Hz. 

hartf36, it is and it is not. Subs are easy to integrate if you have the tools and know what you are doing. Otherwise, it is virtually impossible. For most a matter of luck more than anything. Most are not even trying. They are using a low pass filter only on the subs and not a two way crossover which is mandatory if you want to get it right.

@douglas_schroeder , The best you can do is get the tonal balance right at one position. Move closer and they get bass/midrange heavy. Move further away and they get treble heavy depending on the cross over point. That is just the tonality of the speaker. Because of the disparate radiation pattern and energy you will never get them to image correctly. It does not matter where you put the tweeter ribbon. But, they are your speakers and all that matters is how you like them. The only speakers I have ever heard image correctly remained true to form throughout the audio band. They are a three way ribbon loudspeaker, a three way dynamic loudspeaker and an almost full range ESL. 

@bdp24 , you were humming with the Tympanies but lost it with the ET LFT 8B. It has the same problem as Doug's Aspen Acoustic's speakers just lower down. Have you listened to the 20.7's ? IMHO I think they are Maggi's best speaker ever. I just wish they had made them 8 feet tall. As an aside the pipe for a 16 Hz tone would be around 30 feet long.

@douglas_schroeder, You can look at a bus and know right away that it won't fly even though it is a mode of transportation. You have enough experience to know this. I can look at some speakers and know were their worst flaws are and what they are going to do. Some speakers have fatal flaws, flaws that I can not personally live with or maneuver around.
Many people like their TVs set with over saturated colors. Looks cool but is not realistic. Same with HiFi. The problem is that you know right away you are listening to a reproduction. 
As for dynamics you are 1/2 right and 1/2 wrong. Panel speakers like large ESLs can make bass but they suck at it and fall flat when it comes to low end dynamics. I always thought I could maneuver around that problem with subwoofers. It took 20 years of farting around and digital electronics to lick that problem. As for the rest of the range large ESLs are every bit as dynamic as horns just much less efficient. The snap of a Sonor snare drum is something special to hear on ESLs. They can do this because of the very large size of the panel and their acoustic impedance is close to that of air. Planar magnetics and ribbons are a compromise especially when you start adding crossovers in the midrange. Dynamic driver haven't got a prayer in hell. Distortion is magnitudes higher, they are an impedance mismatch to air, they spray sound all over the place usually indiscriminately and they are severely range limited requiring crossovers not to mention the problems you get into with enclosures. The only advantage they have is size, a huge advantage. The only place they excel over other types is in the deep bass at very long wavelengths. 
The little Maggies do have great midrange considering the price. Given the right amplifier and a decent subwoofer system I can imagine performance exceeding that of most dynamic speaker, certainly anything near their price. 
I like panel loudspeakers for well defined reasons. Modern 8 foot ESLs are handily the best panel loudspeakers. You have to be able to live with the size. As the previous owner of Tympany's, my current speakers are tiny:-)

@b_limo, if you think the LRS's sound good move up to 3.7i's. They should really blow your doors off. From there it is on to ESLs and a supreme state of audio bliss:-)

gumbedamit, the Spectra 33s were not a great example of what Acoustats were capable of. All ESLs require subwoofers to be set free in terms of dynamics. With subwoofers ESLs are significantly more dynamic than Maggies with subwoofers. When you factor in an 8 or 9 foot ESL you are in an entirely different ball park.
Just like ESLs,  Maggies are really bad at low bass. This is a problem all open baffle loudspeakers have. Their midbass is wonderful and the Maggie ribbon tweeter is IMHO the best tweeter made even if it is on the fragile side. ESLs however do not have tweeters. It sounds like you are firmly in the dipole camp. I would not waste more money on the Acoustats. I think the 20.1's are a better speaker. The 20.7's are better but not obviously so. If you want to get to the next level then shoot for large Sound Labs and I promise you will never look back. I am intimately familiar with Acoustat, Magnepan and Sound Labs. I own or have owned all of them along with Apogee Diva's.