Brettmcee - it seems we probably won’t get anyone’s list of top Thiels, in great part because that conversation already peppers these two hundred plus pages. Preference ranking is also a very personal thing and includes personal values and constraints. I can, however, supply some relevant history and perspective that may interest you.
Point one is that each revision of each model represents a step ahead in Jim’s pursuit of the same goals stated for that model at its inception. New drivers are a core element of each iteration. The 5i is merely "improved" because the top 3 drivers remained the same and the woofers are modifications, not ground-up designs. But in Jim’s lexicon a later model is always better.
Point two is that model progressions developed over time rather than some foreshadowed master-plan. The original series 1,2,3,4 displayed Jim’s linearity. The next model would get the next number, not necessarily bigger or more expensive, just chronology. (I tried to make the leading "O" stand for Original, but to Jim it was merely a leading zero to note he planned on more than 9 products. The CS designation changed that. The CS3 would have been the 03b but for Peter Moncrief of the International Audio Review who dubbed it a "Coherent Source" (which of course the 03 and 04 had already been.) So the floor-standing Coherent Sources developed their decimal iterations, the higher the number after the decimal, the more recent and more well developed. Some listeners prefer some older models due to more forgiving attributes in those older models. Note that impedances began around 6 ohms and fell consistently over time to more like half that value.
Point three is that market realities intruded into Jim’s natural rhythm and wishes.
We had developed a fairly recognizable lineup with the CS3 as the rather bold 10" 3-way, the CS2 as its little sister for smaller rooms and lower price, and the CS1 as the little two-way that could hold its own at half the price. The next product in the works was the CS4, which would have been a 4-way, and in hindsight possibly another breakout product like the CS3 had been. Jim was working on the 12" woofer which eventually found its way into the CS7, crossed to a 6-7" lower midrange and a CS2-type small upper midrange, and the 1" ultratweeter that landed in the CS5. The late 80s were high times and many companies were unveiling statement products at 5-figure prices. Add to that, our most enthusiastic high-end market was Japan and the Asians who followed its lead. Japan (and others) wanted more speaker than the CS4, plus in Japanese culture the number 4 is associated with death and myriad superstitious troubles - a model 4 would not fly in Japan. So the 5-way CS5 was developed, leaving the door open for the CS4, which never materialized. In my opinion the CS5's technical difficulties could have been left behind by a CS5.2; but that never materialized.
The 5 was followed by the 2.2 which I consider an in-character small masterwork. Then the SCS introduced the coax to greatly solve the ear-position problem of a portable speaker. It retains its port and its second order crossover from the 02. Fair enough. But the following CS3.6 changes the core DNA of the model 3 to reflex bass and the model 6 and 7 follow suit while side-stepping both bass equalization and sealed bass. They don’t fit quite as neatly into the tacit philosophical matrix. There are many factors involved in my take on the subject. One of those is my departure in 1995, having established our production capability and needing to leave a very hot hotseat of directing manufacturing operations for a production-limited company growing at a self-defined 30%/ year with marketing pressure for greater growth. Add also, Thiel’s entry into "home theater" requiring the development of the feature-laden subwoofers, and the necessary transfer of much of that HT manufacturing to China. The company’s evolving DNA no longer fit my personal sensibilities strongly enough to ride the wild beast.
Let’s address that pesky model 3 bass alignment. Believe it or not, a major component of Thiel’s musical reproduction philosophy rested on solid bass execution from which the harmonic structure of the music arises meaningfully. A sealed bass system pulls off that feat far more deftly than a reflex system in which the 4th order bass alignment places the lowest bass harmonics a full cycle behind the higher harmonics - effectively putting the deep bass 10 or more feet behind the rest of the music. In the day it was called "slow bass". Jim’s equalized bass solved the problem elegantly, but faced significant market resistance. His CS5 non EQ solution required progressively dropping impedance in the deep bass. However, I believe the problems of driving that load could have been mitigated via higher impedance across the board. Jim was insistent that higher impedances "wasted amplifier power". And his word was gospel. A very interesting aspect of Jim’s thinking is his reduction to simplicity. He reasoned that if "some" amplifier(s) could drive the CS5, then any that couldn’t were defective." He always reverted to some version of: "they have an amp problem, not a speaker problem" when addressing difficulties driving the punishing load.
Cutting to the chase, the CS5 failed to meet our market expectations and the CS3.5 EQ was similarly problematic. I believed that we could improve both to surmount their limitations and carve a clear market niche. That wasn’t my call to make, as Kathy as Marketing Director decided that those considerations were too esoteric for a meaningfully large market and that reflex bass was "good enough". Jim set about executing reflex bass very well indeed; but the lagging time alignment is baked into the physics of the beast.
I detect a more avid fan base for the early Thiels where sealed bass is part of the DNA of the upper models and reflex bass is a necessary accommodation for cost-reduction in the lower models. I recognize that my perspective is colored by my own lived experience, and that there are many brands priced up to $Six Figures that rely on reflex bass. Just my take reflects my values.
So, my list of favorites would include the older models, even though their execution is not up to the standards that evolved as Jim learned more about driver improvements and other elements of his art. I have heard that the 7.2 was his favorite all-in (although other stories are out there.) The breakthroughs of the radial wave and star plane drivers of the 3.7 would have opened a doors into a new level of performance and possibilities. But the story doesn’t necessarily unfold as we might wish.
