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Bruce Edgar on Horns...And Amps.
Why Horns?
By Dr. Bruce Edgar Edgarhorns I remember hearing a very good horn loudspeaker for the first time in 1978. It was sheer magic to my ears. I could not believe the incredibly realistic sound that seemed to radiate effortlessly into the room. But when I talk to other audiophiles about horns, the reaction I hear is usually one of disgust. Like a bad hair day, everyone seems to have had a "bad horn" day. Rich Weiner of "Bound for Sound" recently described his "bad horn" day. "As a neophyte audiophile, I once had the horrifying experience of listening to a friend's horn-based speaker system. "Killer equipment. You've never heard anything like it," he promised. Indeed I hadn't. I found myself sitting about six feet from a pair of Klipsch corner horns driven by Phase Linear 700 amps. My friend was right. I have never heard anything like it, although I understand that standing directly behind a 747 during takeoff is quite similar. Since that time I have avoided horn speakers." (Bound for Sound '99CES Report). But times are improving. In the same report, Weiner says, "Perhaps it's time to try horns again...Edgar's Titan (Horn) system was quite impressive...detailed and articulate..." Weiner's experience is not unique. Other reviewers and audiophiles are coming around to the concept of an acceptable audiophile horn system. So you may ask, "What is the difference between the vintage horn systems and the new generation of horn loudspeakers?" I have been researching that question for the last 20 odd years. In the process, I founded Edgarhorn whose main goal is the design and manufacture of audiophile quality horn loudspeakers. But I'm getting ahead of the story. After I had heard my first good horn speaker, I began trying to hear other horn speakers and other pseudo-horns. Most of the ones I listened to didn't come close to that first system that I'd heard. Eventually, I was able to analyze that good horn system to discover what made it tick. It belonged to a Senior Engineer at the aerospace company where I worked. At the time, I was a research scientist specializing in radio wave propagation and signals analysis. The design came from a group of amateur horn builders on the east coast lead by Ben Drisko in the early 50's. This system used a Drisko folded corner bass horn design, similar to the Klipschorn, and a JBL 375 compression driver on a Western Electric midrange horn. The component that made this system so good was the JBL 375 driver. My engineer friend recently bought a set of my Tractrix horns for his 375 drivers. When we tested them, I was astounded by their ruler flat response from 400 Hz to 10 kHz. In the early 80's, I set about tracking down all the horn articles and papers and analyzing all of the published and underground designs. I was very disappointed. There was no clear way of horn design. What was even more depressing was the periodic regurgitation of wrong headed ideas of horn design in articles from year to year that has infiltrated into some horn design software that is marketed today. So I embarked on course of experimentation with horn design and construction. I figured that with my background in wave propagation, spectrum analysis, and experimental physics, it should be easy enough to arrive at a satisfactory design. Was I ever wrong. After 20 years of horn building, I'm still finding new ways of designing and building horns. It's the Edison experience of having to go through all the different combinations and permutations of drivers and horns. And my customers keep coming in with different requirements that change my views and shift the proverbial paradigm. So back to the question, "What made the vintage horn systems sound bad?" There are a variety of problems. I have run into most of the horn problems either in designing my own horns or duplicating somebody else's horn. The first problem is electronics. Weiner talked about listening to some Klipschorns with high power solid state amps. The amps were one source of the bad sound. Horn systems typically have sensitivities of 100 to 108 dB SPL with one watt input. Even at the loudest sound that you would realistically audition any speaker system (95-100dB), the amplifier is only delivering a watt or so to the horn system at peaks. Most of the time the amp is idling at 100's of milliwatts; yes, I said milliwatts. At this level many high power solid state amps have real problems with crossover distortion. For this reason, I tell people who buy my horn systems to try different amps with them along with their existing amp. The low power requirement of horns means that single ended tube (SET) amps can easily fill a room with sound. However, not all single ended tube amps are created equal. Some SET designs have relatively high levels of distortion that can be easily heard on the horn system. And of course, the horn gets the blame for the distorted sound. A second problem with horn loudspeakers is that they are easily prone to resonant peaks in their response. I have heard some horn tweeters that made me think that I was being drilled between the eyes. Many horn midranges have a honky megaphone sound that comes from resonant peaks. I have measured many old horn midranges with high resolution spectrum analyzers and have found them loaded with high Q spikes that give each horn speaker its own characteristic coloration. Bass horns have their own resonance problems. Typically, a well-designed bass horn that can go down to 35 Hz will have a total volume of 20 cu.ft. or more. A company's marketing department will say that it can't sell a big speaker like it. Moreover, the marketers say, "Keep the 35 Hz flare but make it smaller." So the horn length is truncated to make it smaller. The net result is long folded slowly expanding tube that sounds more like a resonant tuba than a wide band bass horn. The response plot looks as a series of harmonically related resonant peaks. Some resonant problems are caused by structural defects. At the point where the sound comes out of the mouth of the horn, the edge of the mouth can vibrate in a bell mode. If you have seen some old style trumpet PA speakers, they were actually shaped like a round bell. A bell will resonate at a frequency whose wavelength can be wrapped around the circumference of the bell end. No horn is immune to bell modes, but proper damping and tension bracing can eliminate the problems. A third problem is the use of improper drivers on horns. Good horn drivers require heavy magnets and light weight diaphragms. Most regular speakers used in typical box speaker systems have lower weight magnets and heavy diaphragms. The use of regular speakers on horns will, for the most part, yield restricted bandwidths and irregular responses. Recently, Speaker Builder featured an article touting an easy horn for your dome tweeter. I performed the experiment with a high quality dome tweeter on a 800 Hz Tractrix horn. Without horn loading, the dome tweeter went up to 20 kHz at a sensitivity of 88 dB. With the horn, the efficiency increased several dB, but the response rolled off above 10 kHz. With such a horn loaded tweeter, any listener would ask, "Where's the top end?" My survey of horn construction project articles has yielded many other examples of using the wrong driver on a horn. As a corollary to the wrong driver syndrome, an associated problem is the use of PA horn systems in home stereo applications. For example, I find many horn enthusiasts over the world using variants of the Altec "Voice of the Theater" (VOT) speaker system. The VOT featured a compression driver on a metal mid horn and a 15" woofer on a front loaded 110 Hz midbass horn. The back of the woofer was loaded by a bass reflex ported enclosure. In general, I have found the Altec compression drivers and woofers to be good quality horn drivers, but the horn design can be improved with my Tractrix horns. And I have done this for numerous customers. |
#2
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wrote in message oups.com... Why Horns? By Dr. Bruce Edgar Edgarhorns I remember hearing a very good horn loudspeaker for the first time in 1978. babble babble babble... This is where it's at: http://www.avantgarde-acoustic.de/ http://www.avantgarde-usa.com/home.html Egdar's stuff has always been obsolete at best. Many would say crap. Cheers, Margaret |
#3
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Margaret von B. wrote snip This is where it's at: Egdar's stuff has always been obsolete at best. Many would say crap. No one says that. But they all say you should use Lysol for its purpose, which they had to quit selling it for, namely cleaning that part of you which is killing us. That or you shoplifted a grouper last week and left it in your purse. Either way, prompt action is called for. |
#4
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Margaret von B. wrote:
wrote in message oups.com... Why Horns? By Dr. Bruce Edgar Edgarhorns I remember hearing a very good horn loudspeaker for the first time in 1978. babble babble babble... Agreed. Edgar's stuff has always been obsolete at best. Many would say crap. Agreed. Regrettably, this quality of tech info is par for the course when you're reading posts by Cal. There's a real story about modern horn design, but much of it is in US patent office documents, authored by a certain Earl Geddes. |
#5
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Regrettably, this quality of tech info is par for the course when you're reading posts by Cal. There's a real story about modern horn design, but much of it is in US patent office documents, authored by a certain Earl Geddes. Except Cal didn't write this, Dr.Edgar did. Dr.Edgar has the academic qualifications plus the finished work product his speakers work and work very well. Kroomel, you do not. |
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#7
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#8
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Arnii Krooliar discovers yet another "liar" among the Normals. Thanks Cal for showing once again that you are a spiteful liar. Thus far in the history of RAO, every single individual who has ever disagreed with Mr. **** about anything has been discovered to be a "liar". There must be thousands of us, all "liars", according to Krooger. What are the odds? ;-) BTW, Turdy, it's been quite a while since I received an email urging me to lay off you out of pity. Well done! And have a good time at church. ;-) |
#9
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If Arny has designed any speakers, I'm totally unaware of it, as is
everyone else. However, I have heard the Edgarhorns, and in my judgment-which by Arny's standards can be no worse than his, since he is not an audio engineer either, but a mechanical engineer who prefers to perfect his debating trade rather than his designs-they are of sufficient quality to indicate Dr. Edgar is competent in the field. Arny's comments are a typical case of the pot calling the kettle black, since he loves to insert little bons mot in his postings engineered to stir up acrimony, such as his recent pronunciamento about avoiding "substandard amplifiers, such as those employing vacuum tubes" in wholly unrelated missives. |
#11
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The Krooborg's kredentials are on display. What's that odd dusky patina on them? Since I have documented[sic] here on several occasions that I am most definately[sic] NOT a mechanical engineer on several occasions So we're agreed -- you're nothing but a Usenet blowhard, full of **** up to your eyebrows. Thanks Mr. Krooger for, finally coming clean about, that, LOt"S. |
#12
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What is your background, Arny?
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#13
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Arny:
That tube amplifiers should be avoided would be some very good advice that all but a tiny but noisy minority of luddite audiophiles agree with. If you accept that MOST musicians, recording engineers, and DIY home listeners building their own amps, and even many solid state equipment designers themselves, generally hold that there are differences between SS and tube amps and that tubes have some advantages (and also disadvantages): that tubes do certain things very well; and that competitive pressure from tube designs has forced improvement in solid state design in the high end of both home audio and pro recording gear and yet hold that those entire above groups are a luddite minority, then you are absolutely right. And from a raw statistical group you are, as you know, right. Add up all the high end consumers spending money in audio saloons, all the members of AES, all the musicians making albums selling enough to even be noticed (and their producers and engineers and studio owners), and all the people building hobby electronics of any type-even those doing no audio or only solid state-and Wal-Mart alone will sell more people some piece of audio gear (such as it may be) in the Detroit/Windsor metro area ALONE. But any kid can see you are comparing apples to oranges, or Ferraris to Hyundais. The high end of any business has small numbers and huge influence. And any kid knows which really matters: the Hyundais will all be recycled in a few years, and the Ferraris will be heirlooms forever. I know you really understand, but pretending not to certainly smooths the debating trade. |
#14
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wrote in message oups.com... If Arny has designed any speakers, I'm totally unaware of it, as is everyone else. However, I have heard the Edgarhorns, and in my judgment-which by Arny's standards can be no worse than his, since he is not an audio engineer either, but a mechanical engineer who prefers to perfect his debating trade rather than his designs-they are of sufficient quality to indicate Dr. Edgar is competent in the field. Arny's comments are a typical case of the pot calling the kettle black, since he loves to insert little bons mot in his postings engineered to stir up acrimony, such as his recent pronunciamento about avoiding "substandard amplifiers, such as those employing vacuum tubes" in wholly unrelated missives. Since when does a giant turd morph into a little bon mot. ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
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#17
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Cal sez:
If you accept that MOST musicians, recording engineers, and DIY home listeners building their own amps, and even many solid state equipment designers themselves, generally hold that there are differences between SS and tube amps Of course there are differences, tubes are inefficient, and prone to high levels of distortion and they wear out faster. The really good tube amps are expenisive and when not clipping sound as good as SS amps. That musicians prefer them is true but IME only for use with their instruments, such as guitar amps. For playback most of the world knows that SS is far superior. and that tubes have some advantages (and also disadvantages): that tubes do certain things very well; and that competitive pressure from tube designs has forced improvement in solid state design in the high end of both home audio and pro recording gear and yet hold that those entire above groups are a luddite minority, then you are absolutely right. You could only be absoultely right if there was a grain of truth in what you just said. Aside from Bob Carver I know of nobody who ever tried to make a SS amp sound like a tube amp. |
#18
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Signal said: I'm surprised there's anybody left who doesn't know that. Turdy was formerly an Assistant Ashtray Designer at Chrysler. Then he got sick and went on disability. That was in the early '80s. Thank god for the welfare state! If only there were employment opportunities for eye gougers. Even Béatrice Dalle refuses to pay for such a service .-( I googled cette femme and here's what I found: "... sensually beautiful-but-blind cab passenger in Night On Earth (1991)." There's also a reference to her playing a cannibal in "Trouble Every Day". Nothing about eyeballs though. Do you get the TV series "Alias"? A recent episode had a cringingly gruesome eyeball encounter. If the Kroo watched it, he probably rushed down to his computer immediately afterward to jack off. |
#19
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"Mike McKelvy" wrote in message oups.com... Cal sez: If you accept that MOST musicians, recording engineers, and DIY home listeners building their own amps, and even many solid state equipment designers themselves, generally hold that there are differences between SS and tube amps **This is muddy thinking. There are generally larger differences between some classes of tube amps than there are between well designed tube amps and well designed SS amps. F'rinstance: A good quality tube amp (say: Audio Research VT100-III) and a quality SS amp (take your pick) sound far more similar than does (say) a single ended Audio Note and the ARC VT100-III. -- Trevor Wilson www.rageaudio.com.au |
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