Thiel Owners

Unsound, you raise a strong, well grounded germ of an idea.

But in my experience and knowledge, active crossovers are a fairly blunt instrument. Their downfall is that they generally assume a very simplistic model of the driver and therefore give a very generalized net filter effect without the necessary interactive nuances between the signal and reactive driver loads.

Those interactive anomalies can be addressed passively. My study of the progression of Thiel designs shows drivers that are better and better behaved as time goes on, requiring simpler crossovers. But they're still not perfect.

As I mentioned way back, Jim's first purest ideal speaker (never brought to market) included separate amps with active crossovers driving each driver with its Zoebel / Boucherot and other corrections attached to it. That hybrid of active / passive offers everything via control of the factors as well as control over or elimination of all the input variables that cause so much trouble (cable reflections, etc.) With the line level signal presented to the inputs, everything else happens "in the box". We decided, as a young, green, minimally capitalized company, that we couldn't afford to educate our customers, as well as the high risk of failure presenting such a wild-card to the market in 1976. Dealers hated the idea of an amp / speaker system that "just worked". Their very existence depended on addressing all those problems . . .

History validates our decision. Today, someone might pull off that feat. I offered this idea (indirectly) to the new Thiel ownership, who thought it quaint and idiosyncratic and didn't want to talk about it.

If a savvy group could buy Thiel's intellectual property (assuming it becomes available), and if the engineering talent could be assembled, I think this solution could make some real waves, especially in how it harkens back to the roots of the company. What if pro-audio / record-makers had such monitors? What if we didn't have to make excuses for poorly produced albums? What if the vast differences introduced by amplifier output particulars modified by cable variables . . . weren't in the picture at all? Just dreaming. 

Thank you for a walk down memory lane.

It seems to me that the eventual future is all digital crossovers and active speakers.  The idea of active crossovers doing the basic separation and then passive components being added to perfect the signal is interesting.  You could have time/phase correct active crossovers that have higher than first-order slopes and then fix driver anomalies passively.  If that's ever been done I've not heard of it.  

I've got some big active ATC 110 ASLs in another system and they use simple active crossovers.  The designer's philosophy (I've read) is that if you make the drivers well enough, you don't need to have complex crossovers.  I imagine if you combined the two types you could drastically reduce passive component count and complexity, have the benefit of higher order slopes, and maybe not lose anything. 

Jon_5912, you beat me too it as I was keying. LOL.

With very broadband response with steep slopes, a driver could operate in its sweet-flat-pistonic zone. I would need convincing that higher order slopes could be "corrected" to actually produce minimum phase additions through the crossover. I've seen failed attempts, but never a success to my standards. It must pass a square wave right through the crossover, to be phase coherent. If not, then not.

A complicating factor is that unbelievably small anomalies of resonance, less-than-accurate transient behavior and so forth, are readily apparent in a minimum phase system, whereas they aren't even noticeable with higher order crossovers. There's the two-edge sword that Thiel lived with during its entire run. I believe that acuity of perception is caused by the ear-brain interpreting the sound-source as "real" rather than an electronic reconstitution. 

Remember, I am not an engineer. I would appreciate being educated as to how the hybrid might alleviate the need for 6dB roll-offs.