While I have heard speakers that I enjoyed that weren't Time coherent I am consistently attracted to speakers that are. To my ears it is important. Dunlavy, Meadowlark, Quad, Spica, Thiel and Vandersteen are. I'm not sure but I think that the ESL Acustats, Audiostatic, German Physics, Huff omnis, Original Walsh, Yankee, Museatex Mel, ESL Sound Labs, Stax, Martin Logan CLS & CLZ might be ? Does anybody know about these last possibilities? |
Some of the Audio Physics and Lowthar(?) designs might qualify. |
Karls, I believe that John Bau of Spica designed time coherent speakers with other than 1st order cross-overs. |
There may be more than one way to skin a cat. John Bau's classic Spica TC-50 claimed time and phase coherence via this arrangement: slanted baffle with cossover: high-pass slope, approximately first-order, 6 dB/octave; low pass slope, fourth-order 24 dB/octave; both drivers connected with same polarity. |
Josephaud, to answer your questions:
(1). Time and phase coherent speakers sound as though they are "cut from one cloth" with less noticible diferrentiating sound of different drivers and cross-overs. They consistently demostrate superior sound staging and imaging.
(2). Because they uses different drivers, boxes etc. Would you ask the same question of different manufactures that share similar design priorities e.g. Acustat or Audiostatic?
(3). Perhaps it takes more talent, effort and expense in design equipment.
(4). Perhaps? Perhaps not?
(5). With all due respect not all people vote you Best Sound at Show. You have never been in the running when I vote. |
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.
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Roy, thank you very much! Perhaps you can discuss the pros and cons of systems using "motion detectors" such as the ones used in Velodyne (not to single them out) products. I'm also curious about what you mean by "PROPERLY" when discussing digital correction and limiting it's range of correction. TacT (again not to single them out) seems to approach this by using super light cones and digital correction and very fast(?) digital amplification with a much higher than usual crossover point, any thoughts on this unique appraoach? As you seem to be saying that our ears can easily confuse room interation with actual direct sound, are you suggesting that bass output (woofers and/or sub woofers) might be best placed well into the room ala' Audiophysics (you guessed it, not to single them out) speaker placement suggestions? Thank you again for your enlightening response. |
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. |
I don't see a web site for Green Mountain. Where can I get info? |
Now we're getting somewhere. Designers sharing the merits and compromises they have to deal with in a decorous forum. As I have previously stated, I am consistently attracted to time coherent designs. How ever, the thought of lobing effects have caused me concern. Perhaps the experts would shed some light on the subject. |
Roy, once again thank you for sharing your expertise. Am I correct in assuming that speakers well executed from the get go can still benefit from all these "tricks" if the tricks are well executed as well? I'm sure I'm not alone in looking forward to your web site. Good luck! |
Pardon my ignorance, but can one mainatin correct time and phase with 12 and 24 db octave slopes? Many seem to say the only way to do this is with 6db slopes. Are active cross-overs different in this regard? Can active cross-overs be time and phase accurate? |
Roy, your a prince. Thank you. |
I don't have the means or ability to test my listening impressions. With that said, I have found the sweet spot of low impedance speakers to be wider in the horizontal plane and narrower in the veritcal plane. Despite the fact that my mother used to teach ballet, I'm not prone to dancing. I usually listen alone. As such it's an easy compromise to live with. Interestingly, the Dunlavy's seem to have overcome a bit of this vertical sweet spot compromise. |
I think we need to remember that active speakers don't necessarily need to be self contained. One could even argue that isolating cross-overs, amps and drivers have advantages. Even in a self contained active speaker, the various components could be modular in design, so that one doesn't have throw the baby out with the bath water. |
Well, Roy you share a quality with Jeff that I truly admire. You speak your mind. You also seem to share the same fault. You condemn those who take a different path. I do think that you seem to be a little overly critical of the "corporate entities". Jim Thiel and Richard Vandersteen both started their corporate entities out of their garages. Those who belittle success doesn't hold much promise for themselves. The designer who lacks 6th grade math skills (and we all know who you are referring to) seems to have fooled his university professors into giving him an engineering degree. This same designer seems to be aiming at the same target you are with his co-axial drivers (the mirror image of a microphone and it's pin point radiation pattern). You find fault with his approach. That's fine, your entitled to your opinion. It's also interesting that his success has allowed him to experiment with designing new drivers, a luxury many competitors don't enjoy. Attacking his education or intelligence doesn't seem like such a good marketing concept. I either don't remember learning this elementary math or never learned it in the first place. I'm sure I'm not alone. You may have just insulted a large percentage of potential customers. Don't worry I'm not that thin skinned. I can't help but feel that one can be opinonated and back up one's position with mathmatical evidence and still be diplomatic. See, I really do want you guys to succeed. I applaud both of you for sharing the evidence that brought about your design philosophies. I look forward to more from both of you and hope you lead others to be so frank. |
Hi Roy. How's the web site coming along? |
Roy, I'm sorry you feel that your the only answerer here. There just really aren't that many people with your expetise, and even less that do who are willing to share it. It is deeply appreciated. Any thoughts on the now defunct Spica claims? |
I'm not sure about the Vandersteens, but, I do think some of Jim Thiel's crossovers are quite complex. I suspect his goal of amplitude coherence has something to do with this. I suspect that the complexity of his cross-overs is what accounts for the low yet narrow impedance of his speakers. Have you ever seen the one Thiel used in the CS-5. Some have criticized him for this, complaining that his cross-overs suck the energy out of the performance and add a veil to the sound. Yet others critcize his products for being too "analytical" and "clinical" sounding. Go figure? Of course due the the mechanical cross-over nature of some of his new co-axial drivers, the electrical crossovers have simplified. On the other side of the spectrum I think that the Meadowlark offerings use a different set of priorities and accomplish their results with a simpler crossover. Mind you I enjoy all of the above manufacturers products. In as much as one can readibly identify from whose pen what product came from, I still think they have more in common than not. To me, there is something that just sounds more "right" about them. |
Can a ported or transmission line design be truly time/phase coherent? For that matter can a dipole or bipole with their trailing backwave be time/phase coherent? I suppose the same question can be asked of omni-directional designs as well. Is a point source design mandatory? Are sealed boxes required? How important is amplitutde linear(ty?) to sucessfull speaker accuracy, especially with regard to the vacillating ability of power delivery by amplifiers and the speakers dependency upon them? |
Karls, I think the issue with transmission lines in this thread may have more to do with time. |
Roy, will you please tell us what the impedance ranges, sensitivity, amplitude response and power recomendations are for each of your speakers? |
