Deang Posted February 5, 2005 Share Posted February 5, 2005 I wouldn't get hung up on the wood Al. Seriously. It just has to be rigid, and strong, with a smooth inside surface. There are some great suggestions in this thread, and I like ALL of them better than wood! What a great forum. Quote Link to comment Share on other sites More sharing options...
tigerwoodKhorns Posted February 6, 2005 Share Posted February 6, 2005 ---------------- On 2/5/2005 11:52:01 PM DeanG wrote: I wouldn't get hung up on the wood Al. Seriously. It just has to be rigid, and strong, with a smooth inside surface. There are some great suggestions in this thread, and I like ALL of them better than wood! What a great forum. ---------------- After posting my last response, I looked at the picture taken down the throat of the horn and realized just how difficult a wood horn would be. I agree with Dean. A fibergalss horn with a rigid structure should do the trick. Fiberglass should not ring like metal and probably will not need to be dampened. Is there some property of wood when used in horn design that I am missing? Chris Quote Link to comment Share on other sites More sharing options...
Deang Posted February 6, 2005 Share Posted February 6, 2005 Well, it's inert -- and it's beautiful. I just see going that route as ending up being hideously expensive -- and QC would be a *****. With a mold and serious composite material -- each one would be identical. What is striking when reading through this thread is how knowledgeable some of you are in this area. One of you should step up, take the bull by the horn (or in this case, the Bull and his horn) -- and lead him to the promised land. That's a big part of what we are about here I think -- helping each other's dreams come true. Quote Link to comment Share on other sites More sharing options...
michael hurd Posted February 6, 2005 Share Posted February 6, 2005 Al, if you intend to make any quantity of horns, a fibreglass unit would make the most economic sense, as you could make several at a time, as long as you have an adequate number of plug molds. The plug molds may be casted in plaster from your prototype, but you will have to sacrifice the prototype to do so. If the prototype were cut into two pieces and you had a way to attach them together with relative precision, then you can coat the inside of the prototye with a lacquer to seal the wood, wax it, and pour plaster into the horn, forming the male plug. After the plaster has set, remove the two halves of the prototype, and voila, you have a male plug. Repeat as necessary to have a few extra plug molds, you should make several horns at a time. You may have to do a slight amount of sanding on the male plug molds to remove the parting line where the two halves came together. Lacquer the bejeezus out of the plaster to seal it, then wax the molds liberally. Then it is time for the gelcoat, which must be sprayed to achieve a depth of 12-15 mils. There are formulations that can be brushed, but they are hard to get a good finish and it is hard to be consistent in the thickness. After the gelcoat has set up, then you may start mixing resin and catalyst and applying mat to the mold. You might find that a small coarse nylon brush and a purpose built roller will work similarly to ensure that all the air is out of the mat, before brushing on more resin and adding more mat. You may alternately use cardbord to lay mat on, and wet mat with resin, then pick up the pieces and place them on the gelcoated surface. A coulple of passes with the roller, or stippling with the bristles will ensure that there is no air trapped, resulting in a weak spot with poor adhesion. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted February 6, 2005 Author Share Posted February 6, 2005 Michael, I think there might be a problem with the first step in making the mold. The masonite I used to form the curved sides has a very rough side and a smooth side. I put the rough side IN! There is just no way I could sand it smooth inside the 1 inch square throat! I would have to make a second horn just to make the mold. I am also concerned about the quantity. So far, only two people have emailed me to express and interest in these. What would the cost be to have somebody make the necessary mold? It doesn't look like this is going to be worth a large investment. Al K. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted February 6, 2005 Author Share Posted February 6, 2005 Michael, Here's a picture looking down the throat of the prototype. What would it take to make a mold of that? I don't see how you cold smooth it out. Al K. Quote Link to comment Share on other sites More sharing options...
dubai2000 Posted February 6, 2005 Share Posted February 6, 2005 Al, you've got mail. Wolfram Quote Link to comment Share on other sites More sharing options...
3dzapper Posted February 6, 2005 Share Posted February 6, 2005 Al, Shlep that thing down to that local boat builder. If he can't do it himself he will probably know the name of a local fabricator who can. Those "stipples" in the masonite might not be a bad thing even on the finished product. Might eliminate any boundry effect which may present itself. Another idea for the driver end would be to slightly overbuild the layup, then boreing it for a 1 1/8" internal pipe threaded piece to be inserted. To use a bolt on horn a standard, availiable adapter could be used. That would eliminate the step to construct a flange onto each horn. Rick Quote Link to comment Share on other sites More sharing options...
Marvel Posted February 6, 2005 Share Posted February 6, 2005 Al, Does the horn flare back out just a tiny bit on the back end (throat)? Some of the tractrix horns do that. That would present a couple of problems with the plug. You would need two pieces to work that. Marvel Can you post the speaker builder article, or email it to me? I have a bunch of 5" drivers I was considering using in a horn like that. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted February 6, 2005 Author Share Posted February 6, 2005 Marvel, RATS! You'r right, the curved parts DOES flare back out a little. The tightest spot is about 1 inch from the throat end but it's only about 40 thousandths of an inch. That might not matter if it was made straight though. Al K. Quote Link to comment Share on other sites More sharing options...
Marvel Posted February 6, 2005 Share Posted February 6, 2005 Although it would complicate it a little bit, the plug could be in two pieces. Foundries do it all the time. (Easy for me to say since I'm not the one building them) Marvel Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted February 10, 2005 Author Share Posted February 10, 2005 Guys, UPDATE: I have found a small company in the next town South of here, about a 15 minute drive, with a CNC machine that is going to make the pieces for the horn. The setup cost will be about what I expected. The production costs will be very reasonable. I will be proceeding to assemble the horn myself, in wood, as the picture shows. Hopefully it will look a bit more professional though! My thanks to verybody for thier suggestions. It is appreceiated! Al K. Quote Link to comment Share on other sites More sharing options...
johnnyp Posted February 10, 2005 Share Posted February 10, 2005 Al, The graph you posted in the first note suggests the K-55-V compression driver was used on all 3 horns (Trachorn vs. K-400 vs. 511b)? They all look pretty close with the Trachorn having a slightly smoother response. Would not a 4" conventional driver simplify your horn and eliminate the need for the complex adapter section and the costly compression driver? What does the Trachorn response look like with a 4" conventional driver? Which 4" driver to use? I think you might generate more interest if you can show a graph of the K-400 K-55v vs. Trachorn with a 4" driver. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted February 10, 2005 Author Share Posted February 10, 2005 John, Bruce Edgar obviously likes your 4 inch driver idea, but I really don't know what the trade-offs are. My main goal was to upgrade the weak point, which is the horn itself an keep the driver. When I replace the K500 horns in my Belles with Altec honrs using the K55 drivers the improvement was far more dramatic than when I later replaced the K55s with JBL 2426h drivers. The bottom line is that there is an infinite number of possibilities for changes. I have to draw a line somewhere! As to the plots, they just compared the horns with SOME given driver that was the same on all the horns. Frequency response is only part of the story anyhow. Intermod tests showed that they were pretty much the same. That's where the driver comes into it. The K55 was undeer 1% distortion just like Klipsch says. The JBL was only marginally better. AL K. Quote Link to comment Share on other sites More sharing options...
3dzapper Posted February 10, 2005 Share Posted February 10, 2005 If any one is interested, here is a link to the complete article. by Bruce Edgar. Click downloads and scroll down to "The Edgar Midrange Horn" There are a number of great resources on Volvotreter's site. Rick Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted February 10, 2005 Author Share Posted February 10, 2005 Rick, Yes, that is the article where the horn I reverse engineered was published. If anybody gets into it you will notice that there is a error in there someplace. The numbers in his table of length versus w/2 is not quite right. It's close enough to what I regerated to confirm the computer program I wrote though. Al K. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted February 10, 2005 Author Share Posted February 10, 2005 Guys, Here's the way my computer program regenerates the horn in Bruce's article. I think it's pretty close. Compare the W/2 column to Table 1 in the article. I think the error in the article is on the height of the jig shown in figure 7. It is shown as 10 inchs when it should be 11 inches. ...................... Top and bottom piece length=11.67 In. ** Angle=34.9 Deg. Mouth dimensions = 9 x 18 ** Tractrix horn Version 1.5 ** dim X W/2 Height H/W Area ** ALK Engineering ** 0.00 1.000 2.000 1.000 4.000 1.00 1.007 2.600 1.291 5.238 2.00 1.073 3.200 1.491 6.868 3.00 1.186 3.800 1.601 9.017 4.00 1.349 4.400 1.631 11.867 5.00 1.567 5.000 1.596 15.665 6.00 1.854 5.600 1.510 20.767 7.00 2.234 6.200 1.388 27.696 8.00 2.741 6.800 1.241 37.271 9.00 3.437 7.400 1.076 50.865 10.00 4.447 8.000 0.899 71.155 11.00 6.120 8.600 0.703 105.263 11.67 9.000 9.000 0.500 161.998 Square throat to 2 In diameter driver adapter thickness=0.86 In. (Fc=284 Hz) to end * Square * File * Throat to mouth length=11.13 In. Input new length (mouth to 2.0 x 2.0 square throat In) > Al K Quote Link to comment Share on other sites More sharing options...
edwinr Posted February 11, 2005 Share Posted February 11, 2005 This is a very interesting thread. Al, you are to be congratulated on such a great project. It would be hard to gauge the commercial success of this project, but based on what I've read here, it should be quite high. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted February 11, 2005 Author Share Posted February 11, 2005 Edwinr, I hope you're right. I will be having enough parts made in the initial run to make 13 horns. Only 7 are spoken for now and those are just going to be prototypes for may speakers and for my "golden ears" friend! $$$$$$$ !! Al K. Quote Link to comment Share on other sites More sharing options...
Rockets Posted February 12, 2005 Share Posted February 12, 2005 Al, here are some sites that may interest you. I wasn't done looking, but honey dooooties are calling http://www.emachineshop.com/ http://www.cfadesign.com/google.html http://www.vatsaas.org/rtv/construction/nosemold/nosemold.aspx http://www.fibreglast.com/ http://composite.about.com/gi/dynamic/offsite.htm?zi=1/XJ&sdn=composite&zu=http%3A%2F%2Fwww.fiberlay.com%2Fhowto%2Fissue1.htm http://composite.about.com/gi/dynamic/offsite.htm?zi=1/XJ&sdn=composite&zu=http%3A%2F%2Fwww.aplicator.se%2Ffiles%2Fman_spra.htm http://www.jamestowndistributors.com/eserv/eclipse.ecl?PROCID=WEBPROC.WOE.AUTH&AUTOLOG=YES&ID_1=3&CLEV=MORE&TRACKNO=0 http://www.vandykestaxidermy.com/subcategory/130/ Good luck Quote Link to comment Share on other sites More sharing options...
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