Time coherence - how important and what speakers?


I have been reading alot about time coherence in speakers. I believe that the Vandersteens and Josephs are time coherent.

My questions are: Do think this is an important issue?
What speakers are time coherent?

Thanks.

Richard Bischoff
rbischoff
Josephaud, let me return the favor,
(1) The fact that you seem to have heard this before suggests that there is consistent consensus in this regard. I was not comparing these designs to yours or any other particular ones.
(2) I think we agree on some level here. It was however the impetus of this thread. I think that cabinet design is also a common consideration in these designs. We are now seeing drivers designed with these considerations as well. As such I don't think that were talking about a preoccupation with cross-overs. In my earlier post I mentioned that I was consistently attracted to speakers that shared this design principle. Considering the variety of speakers available and the limited time we have on this planet it would be foolish for me to ignore this consistent attraction.
(3) I believe that it's possible that some one with an extensive laboratory to miss opportunities for a variety of reasons. With the exception of the original PSB Alpha (considering it's very modest price point)I have yet to hear a product from this famed laboratory that I've enjoyed. Toole is not God and Canadas NRC isn't the only church.
(4) Perhaps is the operative word.
(5) You have no way of knowing just how "seasoned" an audiophile I am. I would venture to say that in the real voting world where votes are backed by real money on real purchases that the designers of "time coherent" speakers are enjoying greater sales and profits than you are. You state that I embrace a belief in low order cross overs despite the fact that in my earlier posts I mentioned that I enjoyed speakers that didn't confrom to these parameters and mentioned that it has been reported that one has claimed success with time coherence with a higher order cross over.

I don't pretend to have your expertise or the means and know how to actually tests the claims of of time coherence. I merely pointed out that I consistently find speakers making these claims most enjoyable.
Mr. Joseph wrote: "I've found that other things such as the dispersion characteristics, smoothness of power response, and clean decay corellate more powerfully with imaging and driver integration."

As an amateur speakerbuilder for about 20 years (who tried it all, even my own version of an ultra-high-slope crossover), and now as a dealer, I have to agree with Mr. Joseph's emphasis on radiation pattern and decay characteristics. I personally would trade off phase coherency in exchange for good radiation and decay characteristics.

I once built a speaker with true a first-order acoustic crossover (which is a helluva lot harder than it sounds). Yes it imaged quite well from the sweet spot, but the timbre wasn't very good. Recombining the same drivers (a Jordan module and an Audax woofer) with a higher-slope crossover at a much lower frequency sounded much better overall.

Ya'll remember the legendary Dahlquist DQ-10? Well, Jon Dahlquist found that he could either align the leading edge of the waveform, or the trailing edge, but not both. After listening tests, he chose to align the trailing edge, as he found that getting the decay right was more beneficial than getting the initial attack right.

Just for the record, I don't sell Jeff Joseph's speakers; he's a competitor. And a damn fine one at that.
Unsound, you may have misinterpreted a comment just as I did when I first read it: JosephAudio wrote "more seasoned audiophiles voted for us at that show than any other system". At first, I thought he meant "audiophiles more seasoned than you" but upon rereading, I interpreted it as "a number of seasoned audiophiles voted for us at that show -- more than voted for any other system". Great discussion but I wanted to help clear up one small but important misunderstanding.
I am not about to slam on Joseph's speakers, because I think that he is correct on many points and certainly the results speak for themselves: a very clean and clear decay and very flat frequency response. These are tremendously important factors, and any speaker designer that fails to perfect them is doomed to failure from the start. In addition, I would not speculate that his sales are poor either; there are few speakers in the world that perform better than his in this regard. In addition, I agree with him fully that first-order crossovers are an absolute bear when it comes to frequency response and driver integration in real space. BUT that doesn't stop me from saying that I still prefer the "sound" of a well-worked-out time- and phase-coherent speaker. Granted, there aren't many out there, but they do it for me like no others can.
Ozfly, at the risk of appearing petty, Joseph still couldn't
know how many of the audiophiles who voted for his product were "seasoned". Ironic that Joseph finds time coherent fans proccupied with cross overs when thats probably the area which sets his products apart from the rest. Like Karls I am not about to slam Josephs products. I'm sure there are alot of people who purchase his products and enjoy them. I wish that he could appreciate the fact the this holds true for other designs. There is obviously a sincere effort to produce a quality product at work. They just didn't work for me.