SunRa said:
Waveguide theory 101.
The length has no effect on the high end. The length is irrelavent actually, its the mouth size that matters. In any waveguide, there is a reflection/diffraction at the mouth from the termination, rounding helps, but you almost can't get it round enough and as the waveguide gets smaller the edge round has to get smaller. At some frequency this inevitable edge diffraction, which is all in phase on axis if the waveguide is round, leads to a hole, then a peak - cancelation followed by reinforcement. This disappears off axis.
As the waveguide gets smaller - the mouth gets smaller - this hole moves higher in frequency and deeper in effect. This can all be seen quite clearly in the three ESP models at www.ai-audio.com. I estimate that at 18" it will go away completely because it is barely present at 15".
There is also a narrowing of the polar response at the lower end of the passband. The wider the mouth the lower this goes and again at 18" it should be below the passband.
Square mouths blur this effect on axis, but the effect is there off axis where a square horn never has the degree of control of a round waveguide. There are ways that I could mitigate this effect and if I continue in this work I'll look into that.
But for now what's available is what's available.
Of course ANYTHING is available if the price is right!
Michael Ando said:
Anytime soon - I would say no. It could happen down the road but there are so many other considerations that I'm not sure that it will happen.
I am supposed to get some waveguides in fiberglass in 12", but I can't promise when that will happen. Seems that my Thailand connection has dried up.
It might be better for you to get the glass ones directly from Thailand. I might be able to get that to happen. If I ever get the ones I've been promised, I'll see if I can get them to send some to you. You have to underatsnd that the ones that come out of Thailand are not complete. You have to do a lot of further work on them to make them useful.
EspenE said:
Its all up to Thailand not me. The waveguides come as shells. The mount for the driver must be attached and the throat generally is not quite precise enough. I fix all of this with a single step by gluing on a mounting plate with epoxy that also corrects any flaws at the throat. But this requires a machined plug/fixture to align everything correctly, at the correct location. This fixture then becomes the mold for the epoxy to finish off the throat. Its doable, but its not easy.
To Europe, shipping from here makes more sense, but to Australia, shipping from Thailand makes more sense.
"Understood, but wiring the crossover is one of the most time consuming parts and my doing it would drive up the price substantially. I just don't see it as an option."
Earl,
It never occurred to me that you would personally construct the crossovers. I assumed you would have this done in Thailand or hire someone here in Michigan to do it. A high school student could be taught to do so and would work for minimum wage.
LAL
Earl,
It never occurred to me that you would personally construct the crossovers. I assumed you would have this done in Thailand or hire someone here in Michigan to do it. A high school student could be taught to do so and would work for minimum wage.
LAL
LAL said:
This makes sense for large volumes, but the volumes are not clear at the moment. I have to assume that I will do everything, as I have been, until such time as "hiring" someone makes economic sense.
The Thailand operation is shut down. I thought that was clear. I am trying to salvage as much of the technology as possible, but everything has to be done here and by me.
chrismercurio said:
First off, I don't solder my crossovers. Solder is a sure road to failure. Mine are all mechanical conncetions.
Its just not realistic to hire someone - anyone - when I haven't got enough business to even support me.
I do hire my neighbor when I need to do eavy lifting, but never to do something that I can do myself.
It really depends.
I live in Santa Clara aka Silicon Valley....and big companies like Intel and Sun have paid internships for college students. Smaller companies and civil posts are generally unpaid. I don't know if dumb enough is the right way to look at it. Some college students don't need to make money, but they all need real world experience. I think you have something unique to offer.
Chris
I live in Santa Clara aka Silicon Valley....and big companies like Intel and Sun have paid internships for college students. Smaller companies and civil posts are generally unpaid. I don't know if dumb enough is the right way to look at it. Some college students don't need to make money, but they all need real world experience. I think you have something unique to offer.
Chris
tinitus said:Is it too early days fore a groupbuy on the raw 12-15" waveguide
does Earl know anything about our groupbuy function ?
lets keep Earl busy to make him stay
I know about the function. If I had an order for say a dozen of each size I could be persuaded to invest in the tooling. The 12" would normally be $250 and the 15" $300. I could do those, by the dozen, for $200 and $250 respectively. I would have to be paid for these up front so as to be able to buy the molds.
Shipping would be extra of course.
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