... or wondering if it has any new insight into horn design.

I did not read the book but I find funny that person who presumably do not “believe” in horn write a review about the presumably horn related book. It would be similar to ask a blind person to make a research about different ways to use colors by impressionists and post-impressionists …

John Atwood wrote:

Where I part company with horn enthusiasts is their persistent denial of horn coloration, or the even more absurd claim that horns have better time response than other drivers (they don’t), or the horn somehow magically damps diaphragm resonances (it doesn’t). The most serious coloration are the modes, or resonances, induced by the horn itself…

I do not know who John Atwood is but he is apparently was catapulted form a different planet….

John Atwood wrote:

To make horns, or any audio device, better, first we must understand how it works, and what causes the faults. Mindless defence of designs that date back to the late Thirties, and have seen little improvement since, has to give way to a better understanding of underlying principles, and most important of all, finding out if the underlying set of assumptions of the design are indeed accurate.

Well, I can stand when people cry about “design” but disregard the “Results”. I understand that they were for many years severally abused in theirs schools and not they pay revenge for that abuse stressing their “knowledge about design”. This would be fine if they in the end of the day were able to demonstrate a superior Sound based upon their “superior knowledge”. Unfortunately it is never was the case according to my experiences. I do not imply John Atwood, I know nothing about him but he sound kind of “recognizable”. Perhaps it would be better for him to be exposed once to a Not-Moronic horn installation (I have to admit – it is hard to find) and then he might reassess his views about the horns?

John Atwood wrote:

The greatest impact of Thiele/Small LF design in the early Seventies was putting bass enclosure design on a rational and predictable basis for the first time in the audio industry. Prior to T/S, bass enclosures were designed by rules-of-thumb that could be off by as much as 6dB - in fact, there wasn’t even agreement how to measure them! After Thiele and Small, modelling provided actual closed and vented-box systesm that were within 0.5dB - or better - of the model. That’s the measure of how just much improvement a more complete understanding can provide. Similarly, Butterworth, Linkwitz-Riley, and modern Target Function Design (computer optimization) crossovers are far better than the grossly inaccurate “M-derived” filters of the late Forties, which were extremely complex and difficult to design - and worse, nowhere close to the performance of a real-word crossover.

It is VERY-VERY-VERY controversial statement.  Interestingly that since the early Seventies, when audio enterprisers accepted “rules of peculiar education” the Sound of commercial speakers begin to go down (with some exceptions of course) and still gradually going down.

John Atwood wrote:

It’s not widely known that horn design hasn’t progressed all that much since the pioneering work of Bell Labs in the late Thirties. This provided the foundation for Altec and JBL theatre horns that became the basis for the modern high-efficiency speaker of today.

Altec and JBL… Good God! They were/are probably the most horrible horn implementations ever were made!!!

John Atwood wrote:

The constant-directivity horns used in theatres and prosound today, unfortunately, are not about fidelity, but delivering peak SPLs to every seat in the house, and using digital EQ as necessary to compensate for the lumps and bumps in the horn response.

Yes, it is correct. There are many-many other reasons. Still, I wonder why John Atwood, acknowledging the very poor and faulty specific implementations attribute the negative results of those implementations to the entire class? If we see a bird with broken wings in the ground then we do not conclude the birds can’t fly….

John Atwood wrote:

It’s all very nice that modern horns for hi-fi are made of NC-milled wood, have Tractrix or other unusual profiles, and have titanium or beryllium diaphragms, but the underlying horn theory is little different than what Bell Labs was using in the late Thirties. So the departures from the theory - the above-mentioned ripples in impedance, time response, and directivity - are still there.

Yes and no. Very little that was done in thirties has to do with result of contemporary horns. Find any Bell Labs, WE or RCA driver, with their original horns and listen it. It will be revolting (despite what the Morons says)  not because the “theory” but because very poor implementation that had no Sonic objectives, and partially for high demand of home listening.

John Atwood wrote:

The most serious problem with existing horn theory is the assumption that the horn is of infinite length, which conveniently sets aside the real-world problems of reflections from the abrupt termination at the horn-mouth, which then travel back into the horn, reflect off the phase-plug or metal diaphragm, and return back to the horn-mouth, setting up a standing-wave.

I believe it was a paragraph about nothing. If you wish to use phrase “real-world problems” then use “real-world criteria to assess the values of those problems. To imply that the “real-world problems” could be viewed only in context of compliance with “irrelevant theory” is faulty things to do.

John Atwood wrote:

Geddes’ Audio Transducers is the first book I’ve seen that sets aside the obsolete Webster theory, with its severe departures from the real world, and uses finite-element analysis instead. With this more powerful technique, the standing waves, or “High Order Modes” as Geddes refers to them, are revealed within the horn. At the lowest usable frequencies, horns behave like open-ended pipes, with a series of pipe modes that start at a quarter-wavelength of the horn length. At frequencies below this quarter-wave, the horn ceases to act like a horn at all, and response and power-handling drop very fast. The “cutoff frequency” of the horn is set by nothing more than the length of the horn, not the mouth size, nor the profile, nor the throat size.

I did not read the Geddes’ Audio Transducers book and I do not take Earl Geddes as something worth any attention. I do it since a last year someone pointed out to me that Earl Geddes is a bit inelectial freand with Wayne Parham, the dirt that runs “Pi Speakers” company. As far as I concern any individual who socializes with Wayne Parham, or even was in proximity of 1 mile from that asshole, should be shot right in his face with any mercy. I’m not kidding and I hope you got the message that I indented to pass. I wish Earl Geddes good luck with his “theories” and with his acquaintances.

John Atwood wrote:

In Geddes’ commercial loudspeaker, the Summa, he takes the radical step of filling the horn itself with damping foam, sacrificing a bit of efficiency, but strongly damping the internal modes. The technique obviously works: the freq response vs directivity curves on the website are the best I’ve ever seen.

There are many “techniques”. The is even a theory (and implementations) of “hard horn”, according which the mouth of the horn is cover by another large diaphragm. Do we design speakers and concepts or we design Sound of the speakers? I did not heard Summa and I also did not heard Pi Speakers. I also, I did not read Mao Dze Dun books and would not go for George W. Bush lectures about strategy of scientific research….

John Atwood wrote:

The superb curves are aided by Geddes’ thoughtful selection of drivers: the professional-grade B&C DE25 for the HF horn driver, and the B&C 15TBX100 15-inch driver for the bass. These are far better than the typical audiophile fare of 87 to 91dB/metre direct-radiator drivers from the usual high-end European sources. I did briefly audition the Summa at the last Rocky Mountain Audio Festival, but in all honesty can’t tell you how they sounded. I’m not being evasive here - as my readers know, I’m as opinionated as anyone in audio - but the Summas were powered by a bottom-of-the-market $200 Pioneer home-theater receiver and a $100 Panasonic DVD player from Costco.

I think George W. Bush should read his lectures in kindergarten, preferable for English no-speaking kind and preferable for deaf…

John Atwood wrote:

If I understand Earl’s comments in Audio Asylum’s High-Efficiency Speaker group; correctly, he believes that mass-market electronics, DVD/CD players, and wires all sound the same, so the intelligent and thrifty buyer should save their money and buy home-theater electronics from big-box retailers. He was serious enough about this belief to rent a room for a thousand dollars at the RMAF show and demo his speaker with the electronics I mentioned above - I’m quite sure he was the only exhibitor using Costco-sourced electronics in the whole hotel. So what did I hear? A very accurately reproduced bottom-of-the-market Pioneer home-theater receiver and Panasonic DVD player. I listened, thanked Earl and his very gracious wife for appearing at the RMAF, dug into my pocket, and bought a copy of his book. If any of the readers of this blog are working on a loudspeaker, you *must* buy this book, and if necessary, get a physics or electronics major to assist you through the math. If any of the readers of this blog are in the market for a horn speaker designed by one of the world’s top designers, you owe it to yourself to audition this speaker. I have no idea whether Earl would respond favorably to having his speaker auditioned with audiophile, never mind vacuum-tube, much less 300B triode-powered exotica. If you read his comments on the Web page and the High Efficiency forum, Earl has strong opinions about the high-end industry, which must have made for some interesting encounters at the RMAF, which is a 100% audiophile show, no home theater on demo anywhere in the hotel. I must confess that I don’t understand Earl’s marketing strategy for the Summa, which is a technically elegant and sophisticated loudspeaker: in my experience, people buying entry-level home theater equipment don’t give a damn about sound quality, and listen quite happily to Dolby Digital, iPods, and MP3-compressed sound all day long. I don’t see how this home-theater demographic overlaps with the potential buyer of a multi-thousand-dollar state-of-the-art horn loudspeaker - the only horn enthusiasts I know are hard-core audiophiles with extensive record (yes, LP’s) collections numbering in the thousands, and have all-tube electronics which may or may not be cross-connected to a home theater system. Serious, extreme audiophiles, not Joe Sixpack listening to Pioneer electronics connected to a 32″ Wal-Mart color TV.

Hold on! Hold on! Whatever Mr. John Atwood, your Earl said is good for him what it has to do with your reviewing of the Lynn Olson’s book. Are you provide YOUR feedback to the Lynn Olson’s book or you keep polishing the Earl Gedd’s car?

John Atwood wrote:

Maybe I don’t get out enough - there are several contributors in the High Efficiency forum who claim to have 1-kilowatt PA amplifiers driving 104 to 108dB/metre horn systems. A quick back-of-the-envelope calculation reveals a system like that could accurately reproduce peaks of 138dB at the listening position, enough to cause extreme pain, as well as immediate and total loss of hearing for life. (135 to 140dB is the sound pressure 1 metre away from the exhaust of a 747 engine at takeoff.)

Well, when you Mr. Atwood, stop to use High Efficiency forum of AA as the criterion of rational and intelligence not to say Sound then perhaps people would take you more serious. It is not only your readers would be benefited but even yourself, and your engineering thinking…

John Atwood wrote:

Yes, horn enthusiasts are - how shall I put this as gently as possible - a little *different* then the rest of the audio world. Some are more different than others. This doesn’t change the fact that horns for the foreseeable future are the kings of wide-range dynamics and low IM distortion, and a tremendous amount of work remains to be done on the underlying theory. If you have a copy of H.F. Olson’s “Acoustic Engineering” or “Elements of Acoustical Engineering” on your bookshelf (and you know who you are), visit Earl’s website and buy a copy of Audio Transducers today. No, it’s not an easy read; it’s intended as a reference text, and belongs on the bookshelf of any serious audio engineer.

Hm, what was it? If it was a review of the Lynn Olson’s book that it was an unspeakably crappy review. If you have Harry Olson’s book then your have to buy Earl’s book… Come on! This is cheap even for the tasted of audio readers who have accustomed to read trivia trash in audio publications. I do not know what Earl writhes, honestly I care less about him because multiple reasons and one of them because his book is too dirty promoted (and this Mr. Atwood’s “review” of the Lynn Olson’s book is one of the illustrations). All that I learn about the Lynn Olson’s book after reading this “review” that it deserver more “interesting” readers then John Atwood was…

Rgs,
Romy the Cat

PS: Hm, after I posted it I realized that Earl Geddes was the person who wrote the book (my current PC suppresses images and I was not able to see the author of the book). I was under impression that Lynn Olson wrote some kind of horn book and John Atwood was trying to review it (the introduction mislead me). In this context my reply would have some “off the wall comments” but I decided to keep it  “as is”, as it was originally posted. I do not think that my major point would change…

guy sergeant wrote:

I feel you may be doing John Attwood a disservice here. There are two reviews of this book. The first one which you quote extensively from appears to have been written by Lynn Olson. The second, much shorter review is John Attwoods. While he does agree with LO's conclusions, you should really direct your assessments of the review towards Lynn Olson. It seems he is the one who has been spending too much time with the 'rednecks' at AA!

Yes, know I understand that John Attwood posted on behave of Lynn Olson but it changes little the fundamentals of that article. My primary dissatisfaction was not with the people but with the fault that they express? Lynn Olson, the Vacuum Tube Valley Technical Editor, should know better then write bogus comments, dipping them into semi-technical souse. Ah, Alteck such a bad speakers!!! Probably it is because the gravity of the Moon affects the force of the suspension of the speaker diaphragm. Ah, my beloved Lowther or Jordan drivers in paper-masher back loaded enclosures with the wings on the side that I call horn sound like crap, presumably all the rest horns sound the same and the reasons are the mouth reflections, infinite length, standing-waves and chain reaction of the empty phrases in my head…  Ah, I put a compression driver inside of a Coca-Cola can and it sound not as good as it should be. Probably it is because the compression idea of the driver is the faulty one… I can go on and on mucking them what it the point. The point would be: learn how to make the horn to sound good and TNEN critique this type of the loudspeakers as a class…

What is an expert? It is a person who is familiar with subject.  How well Lynn Olson is familiar with the subject of horn if even in his writing he brings very controversial evidences and examples? I remember what Stereophile open it’s forums John Atkinson came up in there with the very similar allegation toward the horns. There is no horn lobby in the industry and John Atkinson feel free run his mouth with whatever foolishness he would like to. If tomorrow Wilson Audio or anyone else who pays his morgridge would realize well performing horns to the public then suddenly the none-existing theories of the horns operation would be favoriteably switched toward the opposite direction.

What it all boils down? It boils down to the fact that Lynn Olson, Earl Geddes and presumably John Attwood have very little knowledge and real world experience with the world of properly made horns. However, give that most of their customers are in the very same boat they chose to ridicule horns in order to sell this loudspeakers. What they do basically is following: Did you try to eat shit? It does not taste well, doesn’t it? OK, get instead of shit our new provolone and ham sandwich… I’m sure that there are a lot of AA-level readers who would love to love that sandwich. It looks like Lynn Olson and John Attwood were among them….

Rgs,
Romy the Cat

hagtech wrote:

Perhaps the book falls under the "theory of irrelativity".  I thought maybe there could be a useful tidbit inside.  One good thing about blogs - people may not agree with you - but at least you can safely post an opinion.

I do not know what is in the book. Books, or blogs or talks… they are all the same. I usually do not look for expression of knowledge but rather for non-expression of the very certain attitudes. One of the “red flag” attitudes would be a person who teaches paint mixing but who has no vision but just his “angry engineering expired” hallucinations….

hagtech wrote:

I'm not a loudspeaker guy, yet I keep thinking there is a lot we can do to improve on horns.  Like you said, most of the existing implementations leave a lot to be desired.  Shoot, I don't see how most of the commercial stuff is any better that the original Klipschorns.  But that's just me.  I have yet to hear an uncolored system.  Next horns I'll probably hear are the Azzolinas.

It is very difficult to talk about existing commercial implementations and the most of the DIY implementations not really better. In horn world the DIY mistaken implementations are even more sever then in any other DIY speaker domain. You see, in the horn world there are “culty: foolish “subscriptions” that very severely deceive audio people toward to poor results. Here and there, there are some interesting ideas, including some solution in vintage implementations, but very few people really go into complete superior result out of horns installations…

Anyhow, Azzolina horns should be very purely performing speakers. The ported enclosure and widely operating yellow drivers spell disaster… Actually I do not call the design like Azzolina’s as horns at all. I call it “drivers with wings”. Looking at what Azzolina’s boys do it might appear that Lynn Olson and Earl Geddes is correct and the horns suck…

Rgs.
Romy the Cat

Jim, I know who Earl Geddes is. I think a couple years back we exchange a few emails where his attitude was that although he appreciate and mostly agree with some context of my site but he is not wiling to acknowledge it because he was afraid that any, even virtual, association with me might hurt the publicity of his business - it was actually what he wrote to me. Later I learned that he was seen hang around some dirtiest scams in audio industry, so, he need to develop his “publicity” as far as possible from me as I know the real price of all that crap.

You see, this is the problem with industry people: they are effective only up to point of public acceptance and marketing wrapper-ability. I still do not know how much rational in the Earl Geddes’ loudspeaker. As “a loudspeakers person” I have seen/heard quite a few new interesting and original ideas in loudspeakers, some of them were base upon deep theories. When I was exposed to some of them so far was able to see that all of those inventors do not really realize the level at which the “definition of success” might operate.  They crate in their mind abstract virtual target and build theories to address them. However, the total level of their Sound is/was way sub-qualifying, and those people really have no idea what they dealing with and presume that anyone in audio is easy to impressed as the Moron-infected AA audiences or the bottomeaters from Midwest audio shows. I do not know if it is the case with Earl Geddes but looking at the community of his associates he swims in the very shallow water.

I very much understand his agenda and I have nothing against it. However I have my own agendas as well: I would like to see what else is possible in horn-loaded topology loudspeakers. I spent quote a lot of time, money and interest in the subject and I feel that I posses some more or less interesting results and more or less valuable experience. From the position of my experience I might assure you that the Earl Geddes’ comments about horns, although might have some purely theoretical values, but have no applied meaning. I would like to pay attention that theories do not make the thing work – it only explains the events. The explanations might be incorrect and in that case the explanations-based practice become completely not applicable. It is exactly what happen when Earl Geddes open his mouth about horns. Bruce Edgar, the person who has order of magnitude more knowledge, understanding, practice and education in the horn universe does not feel that any firm theories that he know might explain horns sound in it’s completion and he feels, very much as I do, that in many cases the results from horns are completely erratic. So, the only one ways that I respect in horns is to do the things, to observe the result and then, to navigate yourself to the direction that you feel is more perspective.

Wojtek above said: “I came to conclusion that …. his graveyard system …. is almost the only way to go.” He might not really realize how close he is. If you look at some very few fundamental rules of proper horn installations (like time alignment, narrow bandwidth and proximities from the boundaries) and take under consideration the geometry and size of the horns then very-very few proper horn configurations might be available. In fact for 4”+1/5”+T situation, that do not go down 100Hz, there are no other configurations then Macondo and it is the only way to go… You might change the drivers for whatever you like but the basic configuration would be still there…

Anyhow, unfortunately Earl Geddes does not operate in the word of horn and he for whatever reasons decided to promote his AA-thrill ideas by presenting and attacking irrelevant dead concepts of horns. With the same result he might attack listening condition on Mars or Jupiter and claim that his loudspeakers that might reproduce minus 12Hz would be perfect for a listening room on Jupiter. Once again, I did not read his book and did not listen his drivers but from what I was able to observe about Earl Geddes was not at the level witch might attract my attention. It someone heard what Earl speakers and feel that they do more then “habitual AA sound” then let me know. I doubt…