none of them play down to 200Hz. So they aren't going to reach down to the ranges covered by our servo subs.
Thanks Danny, but I don't think I was clear. The Subs will crossover to a 7" mid/woofer at 60--100 Hz.
I also don't think I am ready to design a dipole yet. I am looking at the sealed back versions of the Mundorf AMT or using a custom built chamber behind the AMT to dial it in. (simular to the tweeter box in the LS-9 you designed).
Other than a well done line source, a stand mount two ways seem to consistently offer the best imaging I have heard. The fact that some current references are more than $20K just makes them unreasonable for us regular folk. I would agree with you that the Scanspeaks are hard to use and seem to need a lot of voltage before they start to sound their best.
I am open to mid woofer recommendations but prefer no compromise designs. The ATD 18W4004's 7" mid woofers are at the top of my short list, but they are Crazy money too.
However If I have to spend $1200. a speaker for drivers and they really sing, I think there is some value there, they will be way cheaper than even a hard to find pair of used Joseph Audio Pulsar's