tigerwoodKhorns Posted January 14, 2009 Share Posted January 14, 2009 Anyway, the calculation from the volvotreter website is figuring the center plane curve of the side of the horn (probably all tractrix calculators are doing it this way). JC has come up with a method that adjusts the math so that the curve that is plotted on graph paper is the "flare" curve, which is the inside joint between the top piece and one of the side pieces of the horn (or any of the other three joints for that matter). The flare curve is slightly different from the center plane curve. I plan to update the other thread once I've had a chance to review the process from start to finish, for myself, and make notes so I'm able to do this again in the future. It's going to be difficult to put into words though. Greg Greg, Is the information available in a spreadsheet? Chris Quote Link to comment Share on other sites More sharing options...
jwc Posted January 14, 2009 Share Posted January 14, 2009 Did the issue of the tilting of this piece ever get resolved. You lost me here. Check out this thread: http://forums.klipsch.com/forums/t/113409.aspx It makes sense, the equation seems to be for the center of the horn, not the top and bottom pieces, so an adjustment needs to be made. Either (1) Edgar made a mistake and did not notice this, (2) Edgar did notice and thought that it was not a big deal, or (3) the thread is wrong and the equation does account for the angle. This is such a hard issue to describe in writing. I think JC and I finally came together on this one. I think we might have been thinking the exact same thing all along, but the communication was not conveying our thoughts so that we both understood one another. Anyway, the calculation from the volvotreter website is figuring the center plane curve of the side of the horn (probably all tractrix calculators are doing it this way). JC has come up with a method that adjusts the math so that the curve that is plotted on graph paper is the "flare" curve, which is the inside joint between the top piece and one of the side pieces of the horn (or any of the other three joints for that matter). The flare curve is slightly different from the center plane curve. I plan to update the other thread once I've had a chance to review the process from start to finish, for myself, and make notes so I'm able to do this again in the future. It's going to be difficult to put into words though. Greg My thoughts on how one should look at this haven't changed. "calculators" need to be looked at for there value of a certain length and certain area for that length to describe tractrix. There are no errors on Volvoteers software. He provides a whole lot more information with his software than just tractrix. I don't use them. Feel free to explore them at you own discretion. Several people have emailed me in the past trying to "understand" how something like these tractrix horns are made. Everyone gets there own "hang up" on how to visualize it. I am not a pro....but.... Let me make it clear again on what this 223 tractrix horn is. It is a tractrix horn. It is exact tractrix from the start to finish calculated for a full space 223Hz. The Information that gothover is posting showing the "flare" is a flare that combined with the constant vertical expansion provided by me....gives a tractrix horn. Preston Tom....right from the get go pointed out how easily some can make the mistake of "calculating a flare" and that when it gets "angled" to form a horn......the tractrix area expansion is no longer perfect. That isn't what happens here. "center Plane" is never used in the design of this horn. Volvoteer has the center plane and a whole bunch more there for you to use if you want. As far as 1.4 to 2". It will be several days before i can get to that. I'm sure someone else here can "make an adapter" for this horn or show how to modify the existing plan for a 1.4". jc Quote Link to comment Share on other sites More sharing options...
tigerwoodKhorns Posted January 14, 2009 Share Posted January 14, 2009 I just looked at the Volvo Treater spreadsheet. Yes, he has everything very well labeled and accounts for the sidewalls. Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 15, 2009 Share Posted January 15, 2009 I wrote an excel spreadsheet for calculating tractrx horns of arbitrary mouth shape....I could plug JC's design in and modify for 1.4" if he's cool with that. Could I get some dimensions on the 2" version just to make sure we line up? Dimensions of the throat, mouth, and overall length of the horn should be all I need. Oh, and the angle of the vertical expansion (though I could calculate that from the above). I haven't work on it in a while, but I've got some manual hooks for calculating corner inserts for making the round to square transition while maintaining a perfect tractrix expansion. Not sure if you guys are interested in that or not. My next goal is predicting polars, but that's a long ways out. Quote Link to comment Share on other sites More sharing options...
Marvel Posted January 15, 2009 Share Posted January 15, 2009 But just to be clear you are saying the constant vertical expansion grew to fast, so an adjustment had to be made in the horizontal flair near the throat. Exactly, that the issue near the throat. Not sure the other issue got resolved as to any of the spreadsheet calcs taking ito consideration the centerline versus the top and bottom at an angle... Maybe Mike figured out how to have that fudge factor calculated in, so the template that is drawn from the spreadsheet isexactly right. JC does his calculations all b hand, so that is different altogether. Bruce Quote Link to comment Share on other sites More sharing options...
jwc Posted January 15, 2009 Share Posted January 15, 2009 Guys. The vertical expansion isn't calculated from an angle although GotHover can get that for you....I think he knows. He could measure it from his jig. Here is what you do......just draw a trapezoid. 2" on the top and 12" (horn height) on the bottom. The distance between these two lines I think is 17.5" (length of horn). Then draw the sides of the trapezoid. That is the vertical expansion. Of note....one concern I have with making the throat smaller for this "Edgar style" tractrix horn. What is going to happen is that the vertical expansion at the throat is a little "faster" than I like. So lets say the thoat is 1.4 x 1.4. At about 1" from the throat.....the width of the horn will be less than 1.4". Then as you get to about 3" from the throat, the width will get wider than 1.4" and keep getting wider. So you can keep the "area' for tractrix correct, but your "bubble" will do a little contorsion at the beginning. The way around this would be to have less height of the horn (less vertical expansion) and make the horn wider. jc Quote Link to comment Share on other sites More sharing options...
Guest David H Posted January 15, 2009 Share Posted January 15, 2009 The approximate angle is 32 degrees total. 16 degrees top and bottom. But like JW stated earlier this information is not relavent. See page 3 of this thread for simplified build info. JW, no need to rack your brain on the 1.4 inch horn for me, I was just posing a question. If I were to build a 1.4, I would modify the height to fit in a KHorn top hat. Similar to how I build the Trachorn Clone. Quote Link to comment Share on other sites More sharing options...
oscarsear Posted January 15, 2009 Share Posted January 15, 2009 A question for JWC. Your measurements show a drop off above 4K. I use AlK's steep slope crossovers which cross at 5.8K driving JBL 2482's. Would these work well, so-so or not so good for amid-range horn? Quote Link to comment Share on other sites More sharing options...
capo72 Posted January 15, 2009 Share Posted January 15, 2009 2482's run out of gas very quickly after 5kHz. I'm looking at crossing mine about 4.5K. Did Al K. design that for you for that driver? Reason I ask is I've thought about contacting him to see if he would design a ESN for my project. Jeremy Quote Link to comment Share on other sites More sharing options...
Guest David H Posted January 15, 2009 Share Posted January 15, 2009 Here are the results on axis inside JW posted on the 2482, looks to be 7db down at 5500hz Quote Link to comment Share on other sites More sharing options...
Guest David H Posted January 15, 2009 Share Posted January 15, 2009 This is with the 2446 driver which looks to be 7db down at 10k, I would have to agree the 2482 rolls off steep at 5k. Quote Link to comment Share on other sites More sharing options...
jwc Posted January 15, 2009 Share Posted January 15, 2009 A question for JWC. Your measurements show a drop off above 4K. I use AlK's steep slope crossovers which cross at 5.8K driving JBL 2482's. Would these work well, so-so or not so good for amid-range horn? I wouldn't hesitate to XO at 5800Hz with my 2446 drivers. Esp with an ESN setup. In fact, I was thinking of using these on a scala bin with a full set of ESN's with the "usual" XO points. The 2482 does start to roll off after 5000Hz on its own. You could get by with 5800 but may want to consider a little lower XO point. From a polar point of view....yes as you move off axis horizontally...you will get a loss after 4K. Its kinda funny...after I posted those off axis curves.....I got a few comical emails about polars.[+o(] I was thinking ALK offered different options for his ESN bandpass-tweeter networks? Like......XO for using with crites Tweeters. jc Quote Link to comment Share on other sites More sharing options...
oscarsear Posted January 15, 2009 Share Posted January 15, 2009 It is an interesting conundrum. I am using the JBL 2404 tweeter which can go down to 4K but Als tweeter XO them at around 5.5K. In other words I have the performance room in the tweeter to make up for what the midrange might be losing but it needs to be crossed lower. I do not know what would be required to make these XO changes plus (believe or not) I keep the crossovers under the house neatly packed in plastic boxes. I will e-mail Al and inquire. Quote Link to comment Share on other sites More sharing options...
oscarsear Posted January 16, 2009 Share Posted January 16, 2009 Here is what I have learned. The 2482 spec sheet does state that it will cross from 300 to 6K and the frequency graph does drop off after 5K. Yet the 2446 gives a cross range of 500 to 20K and it shows a similar frequency drop on these tractix horns as did the 2482 at around the 5K. I sought out the 2482 for the strong low end. It would be better not crossed at 5.8K but somewhat lower but it is not at all bad either. I am using a 2380 clone horn now and the performance is quite nice. The spec sheet 2482 frequency graph was done using a 2366 horn while the 2446 used a 2380 horn. It could be possible that I am getting better than the spec sheet graph shows. Since the 2446 also drops off on these trach horns I do not know how the 2482's would sound as opposed to graph. It would be nice to trial some and listen. Quote Link to comment Share on other sites More sharing options...
jwc Posted January 16, 2009 Share Posted January 16, 2009 I sought out the 2482 for the strong low end. No doubt that this tractrix horn is diving after 5K and even sooner off axis. No matter what the driver. The 2446 seems to maintain a little better after 4K. These meaurements are crude although I think helpful. That 2380 clone is for two way isn't it....is that a CD horn? I haven't listened to your driver but I would love to hear a pair on this tractrix horn. Yes....would be great for the low midrange....that was the goal of the build. jc Quote Link to comment Share on other sites More sharing options...
oscarsear Posted January 16, 2009 Share Posted January 16, 2009 MIne are P Audio Horns from US Speaker. I use them a 3 ways with the 2404 tweeter. I also run a center mono channel using another 2482 and 2404 and a custom XO from AlK. JWC you know my interest in the tractrix horn. For the WAF I would need to be certain these would be worth the cost before pulling that trigger. The 2482 is a warm, clear and deep midrange. The better animal would be a JBL 2480 driver but these are rare and quite costly. I also have a pair of Fane Studio 8M mid range cone speakers that I will someday try out on the Khorns. Those are supposed to be spectacular. Romy the cat says they're a drop in replacement for the midrange on the Avantgarde rigs. Quote Link to comment Share on other sites More sharing options...
jwc Posted January 16, 2009 Share Posted January 16, 2009 GotHover. Looks much better now that the tweeter mount height is shorter. Can you go any shorter? jc Sorry, can't go shorter, it is currently only 1/4 inch taller than the Crites tweeter magnet. You could always just increase the angle of the vertical expansion... bentz... I was thumbing back throught this thread. What exactly do you mean by increase angle of vertical expansion? Are you implying more higher frequencies out of this mid horn if there was more vertical height to the horn and less width??? Closer to a square mouth? jc Quote Link to comment Share on other sites More sharing options...
jwc Posted January 16, 2009 Share Posted January 16, 2009 GotHover. Looks much better now that the tweeter mount height is shorter. Can you go any shorter? jc Sorry, can't go shorter, it is currently only 1/4 inch taller than the Crites tweeter magnet. You could always just increase the angle of the vertical expansion... bentz... I was thumbing back throught this thread. What exactly do you mean by increase angle of vertical expansion? Are you implying more higher frequencies out of this mid horn if there was more vertical height to the horn and less width??? Closer to a square mouth? jc Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 17, 2009 Share Posted January 17, 2009 I was thinking it'd give you more clearance with the magnet of the tweeter since you were trying to get that riser as short as possible. Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 17, 2009 Share Posted January 17, 2009 That 2380 clone is for two way isn't it....is that a CD horn? It's a bi-radial horn with a big ugly slot. The horizontal polars are pretty consistent but the verticals are collapsed:http://www.jblpro.com/pages/pub/components/2380a.pdfThey sound alright I guess. I've mixed in a lot of venues with these horns on the HF. Quote Link to comment Share on other sites More sharing options...
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