Thiel Owners

Unsound - thanks for the links. Indeed direct drive could be awesome with today's technologies. As I've mentioned, active was our starting point in the mid 70s. Wish I could find that first crude research speaker: 10" 3-way with 3 home-brew amps and low-level active XOs. We thought we could create a technical success, but judged the market to be unreceptive to the idea, especially from an unknown start-up.  

Beetle - Thanks for the reference products.
Jim did control out of band problems as you say. However, his major tool was to create mirror circuits for the relevant troublesome resonances - electronic anti-resonance circuits if you will, which cancel each problem in the frequency & phase /time domain. Most of the parts in those huge xo networks are series and parallel shaping circuits to tame the driver misbehaviors through many octaves. Beyond just having the chops to pull it off, a big problem is the parts cost, and the juggling act of what to spend to reach what performance plateau.

In the past several months I have done hours of listening and measuring of my 3.5 with passive and active digital xo. That Thiel originally also explored the triamping active xo makes good sense. The passive xo system still has these problems:
Each speaker has its own min phase characteristic. Minimum phase still has phase change depending on frequency range although "minimal". Only linear phase has a constant phase change independent of frequency range. Overlapping frequency range of multi-speaker systems still introduce phase changes especially with the 1st order xo that allows large overlapping ranges.
The variability of components is not negligible and when measuring each component the factory specs are only an approximation and fine tuning is essential. Taking good and reliable measures is an advanced skill but also frustrating as the components can change characteristics based on temp, load, etc. Then the issue of what differences are audible and not determined by subjective bias requires double blind comparisons. A passive xo system modification is a fair amount of work assuming that needed components are really available. My conclusion so far is that active digital xo system have the best chance to approach the ideal time phase coherent system with linear phase, time aligned, component eq, and even individual room adjusted set up. As it is stated that the speaker and room variables account for the largest part of the reproduced sound quality, it only makes sense to focus any innovations in mastering the active digital xo systems.

GENERAL QUESTION TO EVERYONE:

I bought a pair of genuine Thiel Outrigger stands, but the Ebay seller doesn't know what model they fit. The front two spikes are 13-3/4 inches apart, from center to center . Does anyone know which model(s) speaker they were made for?

Rules - keep up the good work and keep us posted. Yes, the variability, especially with operating temperature, but also with elapsed time and use all require assumptions of what is average. We called that "average operating condition" as 1/2 hour into fairly vigorous playing. Note that the flat impedance curves created by the Zobel filters do a lot to minimize impedance variables.
I suggest more study on minimum vs linear phase. Minimum phase characteristic is where phase follows amplitude as each driver rolls off. The trailing phase and amplitude of one driver is inverse to and cancels the leading phase and amplitude of the other driver and nets to zero. Linear phase does not zero out and results in ringing in various ways depending on the type of filter.