Why not horns?

Herman,
I reread your most recent post. Good information. Thanks.
I'm curious. How exactly did you go about implementing a digital crossover without any phase shifts or time issues?

Hello Herman ,

What brand xover are you using , can it do variable slope as well ?

Weseixas: "Which maggies are we discussing?"

Duke: I probably should have picked one model and stuck to it, which I didn't do.

Weseixas: "A speaker shoot out would be interesting!"

Duke: If a "shoot-out" could be arranged that was satisfactory to both, I'd put my $4k bipolar up against the Maggie 3.6. Shoot me an e-mail if you'd like to explore further.

Weseixas: "I also cannot agree that a horn speaker will sound like a planer."

Duke: I'm not expecting you to agree without an ears-on; just hoping to show enough evidence that you'll keep your mind open to the possibility.

Weseixas: [to Macrojack]"I'm sure Duke is proud to have... you for a customer!"

Duke: I wish!! But no, Macrojack isn't a customer of mine, and now that he has a pair of Bill Woods' speakers it is extremely unlikely that he ever will be. I think he's done. Macrojack is passionate, and so are you. If you two had met anywhere other than on the internet, I bet you'd focus on what you have in common rather than where you disagree, and very quickly become friends.

Weisaxas: "Duke, Ralph, I have enjoyed the discourse and wish you both the best in such a tough business...."

Duke: Thank you sir, and I wish you the best in such a tough hobby!

Prez, you just said "I never said that Thiel was the only time coherent speaker out there"

but in an earlier post you said "A Thiel is time coherent, which makes it unique in this regard."

How can it be unique to Thiel if others do it?

And time alignment is not the same as time coherent.

OK, I read Thiel's description of time coherence, it looks the same as every description of time alignment I've read. I'm willing to be educated. What is the difference?

I have Duo Omegas on top. It is a first order crossover on the tweeter, a single cap in series with the driver.. The mid horn has no passive components. Details on their web site.

My woofer has no passive crossover, it is hooked directly to it's amp just like the mid horn is to it's amp. They are no order, no crossover.

Digital EQ/crossover can be non phase shifting

.

Thank you for added information Herman. I appreciate it.

I suppose I was using the looser definitions of "unique" as in "distinctly characteristic" or "unusual". (Meriam-Webster goes into a drawn out discussion over the battle of useage on this word. Some scholars thinking it should be used in an absolute sense, others giving it broader application)
Anyway, thats neither here nor there. Probably not the best choice of words to indicate that the idea of time coherency by design is exceedingly rare. To the best of my knowledge, only Vandersteen and Thiel on a consistent basis anymore.

My understanding of the differences between time alignment and time coherence comes mostly from those who care about such distinctions. (John Dunlavy, Pat McGinty, Richard Vandersteen, Roy Johnson, etc. Ah well, John Atkinson too)
According to them, time "alignment" is the physical placement of the drivers with the attempt aligning the leading edge of an impulse. Designs with slanted and concave baffles are attempting this. Wilson Audio, the Focal Utopia line, Avalon, etc. are good examples of this.
The distinction between these designs and those such as Vandersteen and Thiel are in the minimum phase filters. Only minimum phase filters prevent a timing delay within the crossover. So, according to them, time "coherency" is when all frequencies arrive at the same time and in the same phase. Since all filters of a 2nd order or higher delay the signal to some degree, only a minimum filter combined with physical alignment achieves coherency.
Things get a little grey when someone like Hansen comes along. Hansen uses minimum phase filters and physical time alignment but inverts the polarity of (If I remember correctly) the midrange drivers. Thus his speakers are time "coincident". Ie, all frequencies arrive at the same time but some will be out of phase.

Thank you for allowing me the opportunity to share this primer. I doubt I did the concept full justice. So at this point, I would suggest reading the Green Mountain Audio site for more precise info. Roy goes into serious detail. Far more than any of the others did. And it's interesting reading to boot!

I'm just starting to understand the realities of varying digital filters and their "orders". But from what I understand so far, even higher order digital filters have timing delays. But, admittedly, I'm still learning about these bad boys. For now I'm only comfortable with analog filters.

But thats why I was so intrigued by what you (Herman) have done! If your digital filters do preserve the time domain then I'll bet that IS one helluva system!
Cheers!