This is my very first build and probably should have started with something simpler but I essentially got a pair of jbl 2226h, 2446h w/2380a and 2241h for free after parting some cabinets out.
While going through the design of the A-290 the only way I managed to match the design output from Yuichi's site is to have an initial T parameter that varies with distance
It sounds odd, but the calculations work and T is changing at a constant rate (+.002/cm), resulting in an error of less than .08% from my calculations to Yuichi's. Does any one know if this is feasible/correct?
I seem to think so because in back calculating T from the design it looks to be varying. I was also able to verify the first set of example calculations and match those 100%.
I am just going through the design to try to learn, CADD the details up and design a router jig to fabricate the horns.
Any help would be appreciated! Thanks!
While going through the design of the A-290 the only way I managed to match the design output from Yuichi's site is to have an initial T parameter that varies with distance
It sounds odd, but the calculations work and T is changing at a constant rate (+.002/cm), resulting in an error of less than .08% from my calculations to Yuichi's. Does any one know if this is feasible/correct?
I seem to think so because in back calculating T from the design it looks to be varying. I was also able to verify the first set of example calculations and match those 100%.
I am just going through the design to try to learn, CADD the details up and design a router jig to fabricate the horns.
Any help would be appreciated! Thanks!
Thanks for the reply! The parameters match my initial ones, hypex, T=.707, Fc=290. Without the T varying the error jumps up to 5% by the horn end. Probably wouldn't make an audible difference but is numerically "significant" error. I just found it curious that it could be resolved in somewhat of a logical manner.
I'm working on a budget version of the TAD exclusive 2402 but based on jbl drivers and hope for a decent result. I will probably add a VHF driver to the set up, but the first priority is to upgrade the 2380a!
I'm working on a budget version of the TAD exclusive 2402 but based on jbl drivers and hope for a decent result. I will probably add a VHF driver to the set up, but the first priority is to upgrade the 2380a!
Jaba, the fins in the initial part of the horn have the benefit of creating a straight wall for construction such as the A290S and also it helps disperse higher frequencies. Don't quote me on that, but I do recall reading it somewhere.
Finding the required thickness is just finding your needed area from calculation and you look at the region between your sub-horn angle (19 degrees for A290) as it's own horn. Like if it was an Altec 803b multicellular horn.
You are restricted by a constant depth of 2 inches and notice that the width of the area between the sub angle is more than needed in calculation. So it is merely the width between the sub-angle section minus the required width dived by two . (taking away the same amount of thickness from each side).
So you are not creating fins, so to speak, but rather creating voids.
Just don't ask me about the two exterior sub horns on the A290, I don't know how those were calculated. To me they should be the same as interior.
But like I said, this is my first build and I'm still learning
Yes, there is, but it's all in Japanese, of course.
However, for all intents and purposes, the first section of the Yuichi horns (those with internal fins) is effectively a "Smith"-type horn, calculated as explained in the original article by Bob Smith (see scans below), with the only difference being that Yuichi used a hypex (hyperbolic-exponential) expansion law, instead of a pure exponential.
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