avguytx Posted June 27, 2016 Share Posted June 27, 2016 (edited) Found this tractrix calculator and was wondering if any others had experience with it or had another recommendation. I'm pretty confident I can build the horns, I just need a little help on the calculating.http://rocketsciencecanada.com/Sound/Horns/TractrixCalc_Mesh.asp Edited June 27, 2016 by avguytx Quote Link to comment Share on other sites More sharing options...
avguytx Posted June 27, 2016 Author Share Posted June 27, 2016 Just to add a little to the above... I already have a new pair of K-33's and this goes back to my Belle clone build. They will be going in the living room for now so the clones will be built to about the same size as original; the top hat having a little room to give for mid horn size. One day when I have the attic finished out, or a different house, I can go larger horn without worry of aesthetics. I'll be using either the Selenium D-250x to start or K-55's and CT-120's or D220ti's for the HF. Quote Link to comment Share on other sites More sharing options...
Marvel Posted June 27, 2016 Share Posted June 27, 2016 A lot of people on here have used Erik Forker's spreadsheet to do calculations. He has moved all of his info to a WordPress site. http://wp.volvotreter.de/ His calculator can be found under the tools link, and it follow the equations published by Bruce Edgar. Bruce Quote Link to comment Share on other sites More sharing options...
avguytx Posted June 27, 2016 Author Share Posted June 27, 2016 Thanks, Bruce. Am I missing where it can be changed from metric to standard dimensions? I'm wanting to calculate it for either Selenium D250x or Klipsch K-55. Quote Link to comment Share on other sites More sharing options...
avguytx Posted June 27, 2016 Author Share Posted June 27, 2016 (edited) The calculator shows you have to edit 4 different areas for designing a horn by throat size. I'm assuming (could be bad) that using a K-55-X or Selenium D-250X is a 1" throat size. For flare frequency, should I work with 350HZ? I've read that the frequency needs to be lower than the crossover point? Also, it shows the ratio of width to height and, if you leave it at 1.5, it makes the horn taller than it is wide and I'd rather have it wider than tall. Does the ratio need to be changed to, say, .60? If I do that, I end up with what seems to be a happy average size of 14-5/16"" wide x 8-11/32" height x 12-5/8* depth. I can build it but I really need help with this part! My best friend owns a company locally that does CAD design for steel structures, etc., and has AutoCAD where these figures can be entered in. Oh, I got the price on cost for a new pair of K-55-X's. They'll be about 4x the price at landed cost. Hmmm.... Edited June 27, 2016 by avguytx Quote Link to comment Share on other sites More sharing options...
Marvel Posted June 27, 2016 Share Posted June 27, 2016 Just sent a message back to you... You have to rotate the calcs 90 degrees. Erik's horns have the sides as flat pieces and the top/bottom pieces curved. Only metric, but you can enter the three columns that are generated as files in Autocad, and it will draw the curves for you. Much easier that drawing out a bunch of points and drawing manually. A 1" throat would be 25.4mm. If you are looking to have a 400Hz crossover, 350Hz for the fc would work. Lower would be better, but your horn will probably get bigger than you want. Bruce Quote Link to comment Share on other sites More sharing options...
avguytx Posted June 27, 2016 Author Share Posted June 27, 2016 Thanks again, Bruce. Isn't the high pass cutoff on a Belle 500hz? Or is it 600? I can adjust that accordingly. I'll probably stay with the 350hz fc for the moment so they'll fit in the top section but later, I'll go to a 200hz horn when they can go on top in the open. Then, I can time align them with a tweeter on top. Quote Link to comment Share on other sites More sharing options...
Deang Posted June 27, 2016 Share Posted June 27, 2016 The K-55 is not a 1" driver. :-) Crossover point should be at least a half an octave above Fc - so I've read. The Fc of the K-400 is 280Hz. I hate horns (unless I'm listening to them). Quote Link to comment Share on other sites More sharing options...
Deang Posted June 27, 2016 Share Posted June 27, 2016 PK used the Type AA for the Belle Klipsch, LaScala, and Klipschorn - even though the Belle Klipsch' horn was actually a 500Hz horn. Quote Link to comment Share on other sites More sharing options...
avguytx Posted June 27, 2016 Author Share Posted June 27, 2016 So they're referring to the driver size or the throat size? I was curious about that part. I knew the K-55 was a 2" driver and had a 1" throat but wasn't sure about what they needed. :-) Quote Link to comment Share on other sites More sharing options...
Marvel Posted June 27, 2016 Share Posted June 27, 2016 (edited) The k55 isn't even a 1 inch throat, it is slightly smaller. Edited June 27, 2016 by Marvel Quote Link to comment Share on other sites More sharing options...
avguytx Posted June 27, 2016 Author Share Posted June 27, 2016 (edited) I remember that too. Something like 3/4" or so. Should I use that in the spreadsheet? Edited June 27, 2016 by avguytx Quote Link to comment Share on other sites More sharing options...
avguytx Posted June 28, 2016 Author Share Posted June 28, 2016 Also saw this line and wondered if it's a misspelling or I'm missing, yet, something else... Throat dimension (with = heigh) If, let's say, the throat dimension is 3/4" (1.905 cm), there's an equation in that box. Does the 1.905 go there or does art of it get entered into that equation? Quote Link to comment Share on other sites More sharing options...
avguytx Posted July 18, 2016 Author Share Posted July 18, 2016 Can anyone tell me which CAD program version works best for entering those "coordinates" and if they are all entered at once or separately? Wanting to start the horns soon. Quote Link to comment Share on other sites More sharing options...
avguytx Posted July 19, 2016 Author Share Posted July 19, 2016 Anyone? Quote Link to comment Share on other sites More sharing options...
Marvel Posted July 19, 2016 Share Posted July 19, 2016 Anything that can run Autocad scripts should work. The spreadsheet generates three columns of the numbers that you should be able to save out with a *.scr and run. I don't have autocad, and I'm not sure what my son used when he made some. Bruce Quote Link to comment Share on other sites More sharing options...
Cantilope Posted July 19, 2016 Share Posted July 19, 2016 Is your goal an exact replica? Why hold to the K55? I believe Roy Delgado is a genius and if your going to take the time to build something, you should consider the 2-way K510 design. One day you might could score a TAD-4002 and it just screws right on there and I think the larger throat sounds a lot better, less compressed. I like the K55, but the K69 is way better and the Beryllium TAD is way way way way better IMHO. I suggest a horn that can use one of these, and I bet you could find a set of the K69 for pretty cheap. I'd bet you a milkshake that if you built both top hats, you'd never listen to the K55 after hearing the other. I'd love to hear a 2-way Belle w/ TAD vs. a Jube w/ TAD combo I bet they are really close. 1 Quote Link to comment Share on other sites More sharing options...
avguytx Posted July 19, 2016 Author Share Posted July 19, 2016 Unfortunately that would be way out of my price range as good as it would be. Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted July 20, 2016 Share Posted July 20, 2016 Unfortunately that would be way out of my price range as good as it would be. K-510 horns (the smaller version of the big K-402 modified tractrix) do sound good. If it is of any help, I do have a single, used K-510 horn and a JBL 2445 driver. This is a good combination. The JBL will sound better than the K-69 driver and there are plenty of them on eBay. Consider trying this as an experiment. If it works, then you would need to find a second K-510 horn (they do come up occasionally). If you are serious, PM me and we can figure out a price. -Tom 1 Quote Link to comment Share on other sites More sharing options...
avguytx Posted July 20, 2016 Author Share Posted July 20, 2016 (edited) I do appreciate the offer but, for now, I'm trying to keep everything under the top hat. Now, when we buy/build a new house and I have them in a separate room, then I'll open up for more options. I know I could build the top section a little taller and get the K-510 in there, though. Hmmm... I have the wood, and capability, of building the wooden Tractrix horn...it's just getting it plotted out. I got the information saved from the spreadsheet columns to a text file and emailed to my buddy to change the extension to a .scr file. Oddly enough, Gmail blocks those file extensions. Edited July 20, 2016 by avguytx Quote Link to comment Share on other sites More sharing options...
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