catapult said:
Yeah the mudslinging is a bummer. Zilch has contributed a lot of interesting posts, particularly on audioheritage.org. But on this forum he just seems to be on a mission to discredit Geddes.
It's getting tedious really.
Re: Re: Criteria:
I don't care if he endorses it or not; we never expected he would. BUT, we DID expect a fair assessment of its performance. Instead, we got a gratuitous condemnation, indeed, a mudslinging, if you will, which does not stand up under objective scrutiny. This thread is about that assessment, and I'm here pointing out that THIS attempt on his part to convince others of the superiority of his product offerings is bogus promotional hype, in large part, contrived at the expense of others pursuing objectives similar to his own.
Look at his statements before and after measuring EconoWave, to paraphrase:
Before: "Why should I even measure this thing? It's a diffraction device, and having measured many similar horns, I know EXACTLY how it will perform. It will not hold pattern to 30°, I GUARANTEE it."
After: "Of COURSE there's not problem with it holding pattern; all diffraction devices do that...."
Seems like he wasn't really happy with the outcome, but his integrity as a scientist mandated that he present the data honestly. That did not, however, preclude him from overlaying that data with his own purpose under the rationalization, "We interpret the data differently," which he commonly employs in these discussions.
As you see, this posed a dilemma for him, as he purports first and foremost to being a scientist. Until he actually measured the device, he had ALMOST worked through that, but once he acquired the data, the "Scientist" hat came off, other priorities assumed control, and it was "Say anything to discredit this thing" time.
We went through that in your spinoff of this thread recently, and it seems you are correct: the result was no better:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=145096
All true, of course, but when he sets out those criteria as a basis of comparison here, it is reasonable not only to consider whether others' efforts satisfy them, and how well, but also whether his own offerings do, also, and with respect to constant directivity, based upon his own data, the answer is clear....
TrueSound said:
I don't care if he endorses it or not; we never expected he would. BUT, we DID expect a fair assessment of its performance. Instead, we got a gratuitous condemnation, indeed, a mudslinging, if you will, which does not stand up under objective scrutiny. This thread is about that assessment, and I'm here pointing out that THIS attempt on his part to convince others of the superiority of his product offerings is bogus promotional hype, in large part, contrived at the expense of others pursuing objectives similar to his own.
Look at his statements before and after measuring EconoWave, to paraphrase:
Before: "Why should I even measure this thing? It's a diffraction device, and having measured many similar horns, I know EXACTLY how it will perform. It will not hold pattern to 30°, I GUARANTEE it."
After: "Of COURSE there's not problem with it holding pattern; all diffraction devices do that...."
Seems like he wasn't really happy with the outcome, but his integrity as a scientist mandated that he present the data honestly. That did not, however, preclude him from overlaying that data with his own purpose under the rationalization, "We interpret the data differently," which he commonly employs in these discussions.
TrueSound said:
As you see, this posed a dilemma for him, as he purports first and foremost to being a scientist. Until he actually measured the device, he had ALMOST worked through that, but once he acquired the data, the "Scientist" hat came off, other priorities assumed control, and it was "Say anything to discredit this thing" time.
TrueSound said:
We went through that in your spinoff of this thread recently, and it seems you are correct: the result was no better:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=145096
Robh3606 said:
All true, of course, but when he sets out those criteria as a basis of comparison here, it is reasonable not only to consider whether others' efforts satisfy them, and how well, but also whether his own offerings do, also, and with respect to constant directivity, based upon his own data, the answer is clear....
Zilch... on diffraction horns, what is your take on the MantaRay style horn? Does it meet the CD requirement?
How about the classic "venetian blind" diffraction lenses?
So, are you then saying that all horns that meet the CD requirement (or are up to your standard on that) are equal?
I mean, what are we saying here?
_-_-bear
How about the classic "venetian blind" diffraction lenses?
So, are you then saying that all horns that meet the CD requirement (or are up to your standard on that) are equal?
I mean, what are we saying here?
_-_-bear
I don't know who first defined constant directivity, but I believe Keele was first to successfully implement it at Electo-Voice. I have never measured the polars on Altec's MantaRays, but they appear to be accepted as CD, yes.bear said:
bear said:
Not CD in the vertical, clearly, as it beams so severely in the vertical as to render it all but inapplicable above 10 kHz, which appears to have been the motivation for Keele's development of Biradial horns for JBL.
As Earl points out, there are different means of achieving, or at least approximating CD, which is generally accepted, virtually by definition, as essential to providing uniform power response. Everyone also knows that horns have long suffered from coloration artifacts which limit their applicability for hi-fi use, where sonic quality now rules.bear said:
Thus, many designers have explored various approaches to improving performance, Earl's work in waveguide theory illuminated some of the relevant factors, and his teachings play a central role in many of these pursuits. Read JBL's PT waveguide white paper I posted above; it is almost as if Earl wrote it.
Earl's oblate spheroid approach is not the only workable one, and as we know, it has its own set of "issues." It's not as if others are ignoring any of this; there are equally viable alternatives which have led Earl himself to conclude that his very narrow definition of "Waveguide" has expanded to become a continuum. Indeed, he concedes that one variant of JBL's Progressive Transition waveguides is "Head and shoulders above diffraction horns," at least based upon measurements posted here....
panomaniac said:
Other people are working on similar things I think.
http://seanolive.blogspot.com/2009/03/binaural-room-scanning-powerful-tool.html
Difference is that the Realiser is available NOW. Likewise Beyerdynamics' Headzone.
Best, Markus
Best, Markus
markus76 said:
True. I was just pointing out what Sean Olive had written because I am interested in the whole concept and thought maybe other people would be interested in what he was working on too. 🙂
Yes, Seans' blog is very interesting stuff. Let's hope that JBL doesn't run out of money to support his efforts 😉
Best, Markus
Best, Markus
Interesting that Studer was doing this 10 years ago. The Beyer Headzone also looks interesting, but costs even more than the Smythe thingy.
It's still a cool idea.
It's still a cool idea.
ZilchLab said:
My thinking on this is that they tend to sound like absolute "dog poopie" for anything other than PA/SR use, so the value of CD response (or not) WRT the things of general interest to me (and I presume almost all participants here) is insufficient to determine worth. It is unclear that anyone wants to use these technologies for PA/SR at the present time either...
Without getting too deep into my own personal findings on the subject, I disagree that "horns have long suffered from coloration artifacts that limit...". There are certainly issues with the way implementations of many horns sound - but to say that horns in general all equally suffer from these limitations is not accurate in my experience. One can even say that a majority of horn set ups are quite flawed - but the question remains as to where the true source of the flaws are. Is it merely that it is a horn, or is it specific to some geometry or other factor(s)?
Let me add that until fairly recently, I would have agreed with your generalization completely. (Fwiw, back in about 1980 or so I would have also told you with certainty that speaker cables made little difference, etc...)
Thus, many designers have explored various approaches to improving performance, Earl's work in waveguide theory illuminated some of the relevant factors, and his teachings play a central role in many of these pursuits. Read JBL's PT waveguide white paper I posted above; it is almost as if Earl wrote it.
Earl's oblate spheroid approach is not the only workable one, and as we know, it has its own set of "issues." It's not as if others are ignoring any of this; there are equally viable alternatives which have led Earl himself to conclude that his very narrow definition of "Waveguide" has expanded to become a continuum. Indeed, he concedes that one variant of JBL's Progressive Transition waveguides is "Head and shoulders above diffraction horns," at least based upon measurements posted here....
Sure, I agree that there have been various approaches over time to the horn issues. I downloaded the JBL paper, but have not read it yet. Just looking at a picture of the horn, it looks like a refined MantaRay, but that conclusion will have to wait until I read it... or someone else draws a conclusion?
If JBL's PT waveguide is "better" than other diffraction horns, it shouldn't be too hard to achieve? (I happen to think diffraction horns are "non-optimal") 😉 My personal experience is that measurements say next to nothing about how things actually sound. They do provide a tool that permits the manipulation of important parameters that permit a user or designer to "see" some of what is going on, or being altered or changed (if you do that). So, I'd base nothing on merely measurements alone. Ymmv.
_-_-bear
bear said:
You didn't ask me to speak to how they sounded. 😉
bear said:
You have misread me. My very best systems here use CD horns.
bear said:
Interestingly, the one which elicited that comment from Earl incorporates a prominent "diffraction device." Despite this, I believe Rob will attest that it sounds very good, indeed....
http://www.diyaudio.com/forums/attachment.php?s=&postid=1519751&stamp=1211726342
I don't see any 'diffraction device' in the throat of the JBL horns. They're certainly better than the 18sound in that way. My biggest problem with them is out at the mouth where they have a sharp edge. Looks like they could use the 'towel mod.' 🙂
Zilch,
I don't want to challenge you on what your "very best system" is all about... no point in that, eh?
I take it that the modified Advents in your video are not representative then??
The horn that you mentioned WRT to Ron seems obviously a relatively recent departure from the standard horn of old, and resembles in many aspects an OS waveguide type device. So, I have not doubt that there are similarities overall, and differences between that and the older type of horn...
What it sounds like, I guess is up to the listener to decide?
It also depends on where you like your HF section crossed in... these devices are a bit to high in frequency for my personal preferences.
Again, I think a lot in terms of the overall discussion depends upon the point of reference from which one speaks... is it the "daily driver", the "Lexus" or the "IROC racer"? Then too, the race car team on the top of the tour how do they look upon the team that continually trails the pack? Point of reference, eh? 😀
_-_-bear
I don't want to challenge you on what your "very best system" is all about... no point in that, eh?
I take it that the modified Advents in your video are not representative then??
The horn that you mentioned WRT to Ron seems obviously a relatively recent departure from the standard horn of old, and resembles in many aspects an OS waveguide type device. So, I have not doubt that there are similarities overall, and differences between that and the older type of horn...
What it sounds like, I guess is up to the listener to decide?
It also depends on where you like your HF section crossed in... these devices are a bit to high in frequency for my personal preferences.
Again, I think a lot in terms of the overall discussion depends upon the point of reference from which one speaks... is it the "daily driver", the "Lexus" or the "IROC racer"? Then too, the race car team on the top of the tour how do they look upon the team that continually trails the pack? Point of reference, eh? 😀
_-_-bear
bear said:
The Advents shown in the video are "entry level" EconoWaves, and the fee is low. There is always room for upgrade. 😉
We use those to illustrate the concept because they are easily modded and routinely available from thrift stores, CraigsList, yardsales, and curbside for $20 or less a pair.
The woofers were also used in the Dahlquist DQ-10 and DQ-20, I believe....
bear said:
Amen to that Brother Bear!
Until about 1984 I thought horns were awful, too. Then I heard what they can really do, if done right. Mostly it's just the implementation that's flawed.
I think the "Newell and Holland" book on "Loudspeakers for Music recording and reproduction" has very good information on this subject. Thanks to Lynn for recommending this.
catapult said:
That's *precisely* what I was talking about.
Quite simply those horns need either a substantial sound absorber near their mouth OR they need a steep high-pass filter far enough from the 1.8 kHz (or thereabouts).
Nothing wrong with either solution.
The critical aspect however will be getting the correct mid-bass driver to work with the higher cross-point and the over-all response off-axis. THAT could be difficult, but I don't think it will be impossible. In fact a mid-range with a cardioid response (achieved by utilizing an aperiodic vent on the side of the speaker), could accomplish this without to much difficulty - AND maintain a good or even excellent linear decay character. If the "EconoWave" were to incorporate THAT feature (i.e. a 3 way with a cardioid mid), then I wouldn't be at all surprised if it was as good or even better than Earl's basic design.
On the issue of diffraction - Earl made his distinction somewhere in this thread. (..though it wasn't something I "bought into".)
I'd like to try the waveguide off the Mackie SRM450. It sounds pretty good - good off axis response. But as it's part of the case, it's gonna be tough to do!
ScottG said:
I'm not seeing that as a problem in the square variants such as the one Rob posted:
http://www.diyaudio.com/forums/attachment.php?s=&postid=1519751&stamp=1211726342
As you might surmise, however, I prefer the shorter rectangular variants so as to minimize the c/c distance between the drivers and move the nulls to the edge or outside of the vertical dispersion pattern.
As a footnote, I don't believe Earl mounted EconoWave on a baffle for his measurements. If not, we're looking at the worst-case scenario with respect to mouth termination issues in those measurements.
ScottG said:
If you read the white paper, you'll see that JBL makes mid/high combination waveguides. Here are some implementations:
http://www.jblpro.com/catalog/general/Product.aspx?PId=148&MId=2
http://www.jblpro.com/catalog/general/Product.aspx?PId=150&MId=2
Also available, separate PT mids with controlled directivity, this one mated with the EconoWaveguide HF:
http://www.jblpro.com/catalog/general/Product.aspx?PId=48&MId=3
It's crossed at 480 Hz and 2.6 kHz:
http://www.jblproservice.com/pdf/PRX Series/PRX535.pdf
To the extent that you believe these issues to be significant, solutions are already available from JBL....
ZilchLab said:
The square waveguide is *completely* different.
It may well have been a "worst case" scenario, don't know - but I'm pretty sure it would still be bad - IF the exit diffraction wasn't "handled" (regardless of its mounting or non-mounting).
Yes, a mid waveguide is *also* another method, and of course it would then have to deal appropriately with it's own exit diffraction. I will say though that while I've never heard these particular designs, that of those I have heard (cone driver + horn), NONE have sounded quite "right" to me.
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