Hahaha ..... I miss the good old days. A gigantic flag ship pair of speakers only costs $25K. Something like this today would be $80K. Nice square step response!
First order/Time Phase-Coherent speakers discussions
"The game is done! I’ve won! I’ve won!"
I would like to use this thread to talk about this subject which I find rather fascinating and somewhat difficult to get my hands on. I went through a course in electromagnetism in college and I have to say this is even more confusing and you won’t find the answer in calculus, physics, Einstein relativity be damned it’s not in there either and definitely not in quantum physics. Listening to the "experts" from Vandersteens and Stereophile but ultimately it all came down to a missing link sort of argument ... something like this:
"Since if a speaker can produce a step response correctly, therefore it is time-phase coherent, and therefore it must be "good".
It’s like saying humans come from chimps since they share 90% genetic content with us, but we can’t find any missing links or evidence. FYI, we share a lot of gene with the corn plants as well. Another argument I’ve heard from John Atkinson that lacks any supporting evidence and he said that if everything else being equal, time-phase coherence tends to produce a more coherent and superior soundstage, but to the best of my knowledge, nobody has been able to produce some semblance of evidence since there is no way to compare apples to apples. Speaker "A" may have better soundstage simply because it’s a BETTER design, and the claim "time-phase coherent" is just a red herring. There’s no way one can say the "goodness" from "time-phase coherence" because you can’t compare apples to apples. Ultimately it’s a subjective quantification.
I’ve been doing some simulation and I will post some of my findings with graphs, plots, actual simulation runs so that we are discussing on subjective personal opinions. Some of my findings actually shows that intentionally making time-phase may result in inferior phase problem and NOT better! (will be discussed more in detail).
Having said all that, I am actually in favor of first order/time-phase coherent if POSSIBLE. I am not in favor of time-phase coherence just for the sake of it. It’s just that there are a lot of mis-information out there that hopefully this will clear those out. Well hopefully ...
Here my preliminary outline:
1. My "subjective" impression of what is "musicality" and how it’s related to first order filters.
2. Interpretation of step-response. I’ve read a lot of online writing with regard to the interpretations but I think a lot of them are wrong. A proper interpretation is presented with graphs and simulations.
3. A simulation of an 1st order and higher order filters with ideal drivers and why time-phase coherence is only possible with 1st order filter. This part will use ideal drivers. The next part will use real world drivers.
4. A simulation with actual drivers and how to design a 1st order/time phase coherent speaker. Discuss pros and cons. And why time-phase coherence may actually have phase issues.
5. Discuss real world examples of time-phase coherence with Thiel’s and Vandersteens speakers (and why I suspect they may not ultimately be time-phase coherent in the strictest sense).
6. I’ll think of something real to say here ... :-)
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I liked this in the review, " The tendency of many high-end products to attempt to "fix it in the mix," as audio engineers would say (ie, attempt to "improve" the realism of the original source material), is not in the best interests of ultimate fidelity. For audiophiles who value accuracy over euphony, products like the Dunlavy Signature SC-VI loudspeaker are a breath of fresh air in a landscape polluted by pretty-sounding panderers. |
Hello Andy! I enjoy your posts. Thoughtful and intelligent; we are both music lovers and audiophiles. I need to explain again how I got myself stuck into giant speaker project as described in my very first post ever on any website, being forced into doing this by one of the four (now five!) audiophile friends who pushed me at age 81 (now) to jump into speaker design again. After retrieval of my notes from museum and study of topology (a favorite of mine from graduate-school network-theory courses) I tried a merger of "constant-resistance" network theory into my "Infinite-Slope" in my previous patents. First try was a 2-way series crossover at 2KHz. Installed this into Parts-Express 2-way speaker kit with test measurements in my home lab and also in anechoic chamber of Tech Center at Binghamton university. Waterfall plats, frequency-response, input impedance, delay response, all looked good, even surprisingly so. Even more so as I examined in detail match at the 2Khz crossover, it was seamless with no evidence of a "join" in either frequency or phase response. It was time to listen to music on this box and as in my earlier post, I burst into tears at first listen (I'm Italian!). Never in my life did I hear that kind of sound come from a speaker box! Emphasis needed here: I'm no genius. This result was a pure accident of discovery, nothing more, and certainly not expected. My audiophile friends came over for listen and forced me into building three Parts Express kits to listen to until I could come up with a 3-way crossover for their Joseph Pearls (Successful as mentioned in last post)! I should mention a funny effect I observe in audio showroom where we were comparing my invention with other speaker systems, as someone wanders in and after a few steps they stop dead suddenly at the sound! It happens every time one hears my invention for the first time. In closing I'm actually sorry I hit upon this thing, I nearly gave up and burn my notes and abandon patent, but it's too late; I need to see this thing through. Did a public demo of invention in August before an audience of 300 at a symposium with speakers as subject with incredible results (I hope to see this publicized in Winter quarterly journal of organization which invited me), one speaker manufacturer there asked me to try my invention; gave me data on their drivers. This is a Winter project ongoing. RIMO |
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