Thanks, Duke, for sharing this with us, it's something I've always wanted to see.
15 responses Add your response
Nobody I know calls themselves Dr. Doe, rather John Doe, PhD or MD or DDS or ED etc. I didn't get an indication of whether Geddes doctorate was in acoustics, EE, medicine, dentistry, education or that rare specialty of a PhD started by S. S. (Smitty) Stevens at Harvard called psychophysics, a multi-diciplinary degree based on knowledge of the stimulus (e.g. acoustics), physiology, and perception.
I think you'll find Earl's book to be much more than a translation for laymen of existing conventional texts. Earl's thinking isn't limited by convention at all.
RCPrince and Jfz, thanks for the thumbs-up! RC, Earl told me that he's been wanting to write this book for a long time.
Donbellphd, I called him Dr. Geddes, so if someone was out of line in using that title it was me. My dad's a medical doctor, and I'm used to hearing people call him Doctor LeJeune instead of Francis LeJeune, M.D. Earl Geddes has a Ph.D. in acoustics. Here's a link to his resume', in case you'd like to see it:
Thanks for the link to the resume. I didn't get much out of the first chapter, but I applaud any effort to bring rational rigor to sound reproduction as realized in the home. High-end audio is an area of too much mysticism, with "audiophiles" claiming to hear all kinds of things from all kinds of sources. The reproduction of music has by its very nature subjective goals, because systems rarely sound the same, i.e. each distorts in its own ways. But preference for particular distortion does not equate to superiority. Although there is a good deal of science behind the design of a first rate component, there is also an aspect of art, a balancing of choices by the designer.
Judy426 - My association with Earl Geddes (mentioned in my initial post above and on other threads) has been both business and personal. I've never gone into great detail about it, but maybe now's the time.
Roughly four years ago, I decided that what the world needed was a new pair of loudspeakers. What I wanted to do was use a 90 degree pattern constant-directivity horn, crossed over to a 15" woofer at the frequency where the woofer's pattern had collapsed to 90 degrees (the idea being to thus minimize discrepancies between the direct and reverberant sound fields) . I thought this was a great innovation, not realizing at the time that JBL had already done exactly this twenty years earlier in a large pro-sound studio monitor. Anyway, I contacted a professional loudspeaker designer that I was friends with (Alan Hulsebus of Orca Design), and he directed me to Earl Geddes, describing him as "the world's foremost expert on waveguide design". I had seen the name before, as one of Earl's inventions is described in the most recent edition of The Loudspeaker Design Cookbook (I'm a long-time amateur speaker builder).
I engaged Earl as a consultant to design a waveguide for me, and subsequently Earl and his wife visited my wife and me in New Orleans for Mardi Gras. As the speaker design moved along, Earl proposed that we become partners in the development since the basic format of the design was something that he had wanted to do for years. My wife and I joined Earl in a week of prototype development at a facility in Maryland. Unfortunately I soon had to drop out as a partner because of financial difficulties, but remained very interested. The speakers (called the Summas) were developed to completion by Earl, and I became a dealer for them. My wife and I consider Earl and his family to be our friends, and we manage to get together every now and then.
When Earl wrote "Premium Home Theater", he sent me drafts of some of the chapters and I sent him my comments on them (pointing out parts that I couldn't understand, etc). Earl sent me a draft of the first chapter of "Audio, Acoustics and Perception", and evidently found my suggestions helpful for he offered to pay me for being one of his proofreaders. I told him that, once the book has been printed, if he has found my suggestions to be worthwhile to pay me with several hard copies of the book rather than with cash.
Earl's main line of work is consulting, but he has long wanted to write this book because this is where his passion lies. He didn't ask me to post anything about his book being available free on the internet, that was my idea. I think it's a wonderful opportunity for those of us who are interested in the subject matter. There's nothing (not even a request) to restrict anyone who wants to from downloading and saving copies of the chapters as they appear. The eventual hard copy will of course be neater and may include some minor revisions.
This may be more information than you were asking for, I don't know. It's a judgment call as to where industry people posting an "informative" post morphs into "advertising", and where "not posting information" morphs into "hiding something". I've called it wrong both ways at times.
I considered explicitly stating that I am a dealer for Earl in my initial post here (my minor proofreading role is pretty inconsequential), but decided against it as that could easily come across as "advertising" - the implication being "if you liked what you read in the book, now come spend your money with me". As I said, it's a judgment call and there's a 50-50 chance I got it wrong.
Directivity speakers that VMPS will be showing at the CES quite interesting. How about a 180 degree power response from 280hz on up? This new waveguide technology is patent pending and is novel.
The planar and ribbon drivers of Vmps speakers will now have 180 degrees of dispersion. This will be measured and posted at the Vmps forum at audiocircle. The tests will be conducted by a known engineer and audio journalist. I'll add that I've become a dealer for VMPS in the Northwest so caveat emptor. For those of you who know Brian you also know he's not one to hype. First reports are very interesting indeed. Cheers