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Old 12th July 2007, 03:10 AM   #1491
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Default Name makes it sound better?

How about Openbaffle instead of Open Baffle?
So, now we get farther and farther from some actual useful help.
I want basics. Something in the shape direction would allow bunches of us to start playing.
Lynn .. I've read most of the construction procedures you did on the Ariel. Was great and I learned a lot, but did not need intricate detail of superfitting joints. You know, as well as most here, that it was overkill by bunches. To do cnc multiples is very helpful, but not us Skil Saw guys. And when it comes to gluing I cannot wait for 30 or more threads on who is right. After someone goes thru a month or so to do traditional Hyde gluing process, most of us white glue slingers will be done. I certainly don't mind the furniture makers here to do some terrific structural work. Some things must and should be addressed of course, just not 2 months worth for each item. That's an indication of the theoretical talkers vs. the doers. I didn't get to 9 1/2 fingers by typing.

Here is example of DIY project that worked well ... http://www.hometheatershack.com/foru...explained.html
Granted was not as ground breaking, but continued shelved subs to a different level.
Steve explained his position and 5 pages later an estimated dozens were built and improved.
Zene
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Old 12th July 2007, 03:13 AM   #1492
gedlee is offline gedlee  United States
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Quote:
Originally posted by noah katz
Earl,

"You need to defend the conical horn because you use them, and I need to defend the OS because I use it. "

Perhaps a semantic distinction, but is it incorrect to say that your waveguide is a conical horn with an OS throat-to-horn transition?
This discussion belongs under my topic "Geddes on waveguides".

Precisely, no, an OS is not a conical horn with an OS transition. The OS asymtotically approachs a conic in the limit as it becomes very big, but at no time is it exactly a cone. And where it is the most different is where it matters most.
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Old 12th July 2007, 03:26 AM   #1493
gedlee is offline gedlee  United States
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Quote:
Originally posted by mige0
Hi



If understood right, the OS is a curve that minimises diffraction / reflection when transitioning from the ( hopefully ) flat wave front of a given aperture into the throat of a WG or horn ?

The OS curve starts parallel to the axes of the speaker or at the angel of the compression driver exit ( 6,5 degree ) and converges to the final horn / WG angel like sort of a hyperbolic curve. ?

IF we assume that diffraction and reflection also occurs when mounting a speaker into a flat baffle ( at the speaker NOT at the edge of the baffle ) then there may be a optimal 90 degree curve that behaves better than mounting the speaker flat onto a baffle, no ?

Am I confused?


Greetings
Michael
If I udnerstand the question correctly (and I am not sure that I do) that shpe would be a large sphere. It has a flat surface at the source and curves away at the most gradual rate. Although, a more precise curve would be whats called an Oblate Spheriod of which the OS curvature is a section of revolution. But these two shapes would once again become the same as the spheriod gets larger. For a smll finite enclosure the Oblate Spheriod may be marginally better, but I would guess that this shape difference from a sphere would not be all that significant. To the extent that real drivers are not flat, there probably would be a more optimum shape that "best fit" a real cone driver or a dome driver, but the mathematics of this would be very difficult. There are several AES papers on this topic that you should read.

But, once again, I think that the question presupposes using a direct radiator and what waveguide works best for them - thats not the right approach. The best approach, if one wants to use a direct radiator, is to use a phase plug to better couple the diaphragm to permissable contours (like OS). I am currently doing a lot of work in this area, which is not complete, and is proprietary anyways. Our 2nd generation products will have this feature. A dome radiator costs a lot less than a compression driver, but, just putting a dome radiator on a waveguide is not the best solution - a phase plug helps a lot. But this phase plug is not a trivial thing to design. Our SP line will have a 1" dome (dirt cheap!) coupled to a phase plug and waveguide for a semi-direct radiator waveguide assembly. This cuts costs dramatically, but certainly does not work as well as a good compression driver. So if cheaper is the goal then this might be attractive, but if performance is the goal then the compression driver will win out every time.
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Old 12th July 2007, 05:30 AM   #1494
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Default Re: Name makes it sound better?

Quote:
Originally posted by Zene Gillette

Lynn .. I've read most of the construction procedures you did on the Ariel. Was great and I learned a lot, but did not need intricate detail of superfitting joints. You know, as well as most here, that it was overkill by bunches. To do cnc multiples is very helpful, but not us Skil Saw guys. And when it comes to gluing I cannot wait for 30 or more threads on who is right. After someone goes thru a month or so to do traditional Hyde gluing process, most of us white glue slingers will be done. I certainly don't mind the furniture makers here to do some terrific structural work. Some things must and should be addressed of course, just not 2 months worth for each item. That's an indication of the theoretical talkers vs. the doers. I didn't get to 9 1/2 fingers by typing.

Here is example of DIY project that worked well ... http://www.hometheatershack.com/foru...explained.html
Granted was not as ground breaking, but continued shelved subs to a different level.
Steve explained his position and 5 pages later an estimated dozens were built and improved.
Zene
One thing that's different about this project is I'm describing it as I go along - working without a net, as it were. Most people (including myself with my other projects, including the Ariel) usually take the safe route of describing the project after it's been completed. This has the wonderful advantage of concealing all of the false starts, dead ends, outright mistakes, long periods of staring out the window, utter confusion when the project encounters a difficult part, and the worst calamity, the horrible realization that project cannot work as conceived. I've been in all those places before, and truth be told, I'm pretty sure all audio designers have too - they just don't admit it in public.

I took a smaller risk when I wrote about the Ariel as I designed it, and wrote about it in each successive issue of Positive Feedback magazine. It was still a risky thing to do, since the project could have been a complete flop, and I would have had three magazine articles about building it. By the time I migrated the PF articles to the Web, I could conceal my tracks a bit and tidy up the language of the original articles, giving the impression that I was calmly describing a tidied-up, finished project, describing all the little items learned along the way.

If the Big Accident hadn't happened, I would have been quietly doing all of the research by myself, telling only a few people about it, cruising below the surface on many threads here, spending a fair amount on drivers, building a compilation of measurements, and doing a lot of listening. My goal was to spring something new at this year's RMAF and surprise people, and maybe write about it a year or so later.

The accident completely derailed the timetable. Right before the surgery on January 8th, the surgeon said I'd be walking again in 8 to 10 weeks. That's not what happened - in fact, for the first two months, there was no visible progress on the X-ray at all. I was getting a little scared, actually.

Any thought of getting involved in any kind of recreational/hifi activity went completely out the window - the priority was now getting bone regrowth started and keeping my sanity over the long haul, since at that point it occured to me that I really had no idea at all when I'd be walking again. Reading about "non-unions" on the Internet didn't help things much - the only (small) consolation was that was fairly rare. That is a thin consolation when months are going by and seasons are changing with no apparent progress. It is not fun being disabled. Graduating out of sponge baths in the downstairs guest bathroom and advancing to sit-down showers in the upstairs bathroom was a huge milestone - one that took six weeks!

When the metric is a modicum of personal dignity, won after what seems like a very long time, hifi gets put pretty far on the back burner. Bud had the kindness, compassion, and wisdom to call me out of the blue and suggest I get involved in a project. He knew from personal experience that I was now at a state where I needed something other than self-reflection - and self-pity - to get on with my mental and physical healing.

Having lost all of my dignity during the first weeks of this experience, the risk of looking like a fool on the Internet seemed like pretty small change. I didn't care - and to some extent still don't. An experience like this changes you. So what if people think I'm some kind of New Age wacko, or a self-absorbed dilettante. Big deal. Compared to the terror of going in and out of shock on a sub-freezing day, having your *** hang out at the hospital and being able to do nothing about it, or looking out the same window and seeing winter change to spring and then summer, a little embarrassment on the Internet doesn't seem like much.

So this is nothing like a nice, neat, tied-up-with-pretty-bow all-ready-to-build project. Nope. That would have happened a year or two from now, when I felt moved to describe the new speaker, and do a little bragging on the Internet how clever I was. That's not how things worked out.

It probably sounds rather self-absorbed, but the real reason for this project is to keep my sanity during one of the most difficult periods of my life. Sometimes I think, well, other people have it worse, much worse, but instead of being a consolation it's just a deeper glimpse into the more terrible aspect of the world. That is not where I need to go. I need to create something beautiful - the world already has plenty of ugliness and horror, it doesn't need any more, not from me nor anyone else.

So a design project that under normal circumstances would be private, quiet, and shared with only a few hifi friends is being conducted right out in the open, right here at diyAudio. This is a practice audio designers shun for very good reasons - looking stupid in public being the foremost of them. It's easy to brag about completed projects, just as pro photographers only show a tiny fraction of what they shoot - the good stuff, not the duds.

P.S. The question about the name is a good one. I don't usually name my projects until I have a good sense of what they're going to sound like - not there yet. Maybe by the RMAF. I've got several candidates - Athena, Aphrodite, Eleusis, and a few others.
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Old 12th July 2007, 06:43 AM   #1495
jamikl is offline jamikl  Australia
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I have to say, as one who comes from a non scientific background with no tertiary education whatsoever, that I have enjoyed this particular thread and like others, I,m sure, have already learned a great deal from it. At times it is so far above my head that I feel very miniscule on this earth but I stay with it because I have the deep down belief that some great will eventuate from it. I know that I will probably be able to afford what is to come but I believe it will help me to better with what I can afford.

There are other threads which go on in a similar way but leave me thinking more like Zene Gillette and one or two others. I don't understand the science involved and I don't understand why when we are told that a spreadsheet for a waveguide is not accurate because it is out by a few thousandths of inch we then find find that the waveguide has to be filled with foam to mitigate the very things
the accuracy and shape of the waveguide were meant to reduce.
That feeling does not apply to this thread and good on you Lynn Olson for starting it.

I hope that both your health and your project work out well for you and thank you for sharing part of the journey.
jamikl
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Old 12th July 2007, 09:25 AM   #1496
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Quote:
Originally posted by salas
I would just name it 'Open Wing'.
Given what triggered this project (Lynn's broken leg) and the current level of ambitions I would call it ....

Icarus

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Old 12th July 2007, 11:51 AM   #1497
Salas is offline Salas  Greece
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Me Greek I proposed an English name and all others are proposing Greek names! Seriously now, Icarus encompasses the 'open wing' (which hints to the principles of the project), but his story tells about ambition and failure. Hmmm. Lynn will come up with some Hindu or Hawain name in the end I think.
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Old 12th July 2007, 12:52 PM   #1498
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Default Icarus

Aside the jab about escaping from "prison" it can also serve as a sober reality check when having too high ambitions.

IOW, bluntly: Lynn, we* really want to be both willing (as in: recognize the applicability/usefulness of) and be able to clone (skills, price) the final setup. That apropos the aforementioned open source, community and all that jazz.

But you knew this already w/o me climbing on the soap box

Rgrds, and heal fast,

Florian

*: Whatever we means, but at least more than 1.
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Old 12th July 2007, 07:21 PM   #1499
pdan is offline pdan  Europe
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Lynn,

For my part I'm extremely grateful you started this tread. It has been fascinating, enthralling even, to listen in on the thought processes that go into high-end design.The thread has become a store-house of info for the benefit of all builders of loudspeakers; whatever design is being contemplated.......There is gold in them there pages.

"Aphrodite" ?.......nice possibility. After all She was married to the lame God Hephaestus. A master designer and builder.

Just off to sing a paean to Apollo for your speedy recovery.


Cilla
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Old 12th July 2007, 08:03 PM   #1500
Pano is offline Pano  United States
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Quote:
Originally posted by pdan
"Aphrodite" ?.......nice possibility. After all She was married to the lame God Hephaestus. A master designer and builder.
Brillant! Love it.

But lets not forget one other thing Hephaestus created - Pandora. Has this thead opened the box?
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