Arash Posted December 24, 2014 Share Posted December 24, 2014 (edited) the other week I tried to engrave a horn into MDF and the result was stunning. sanding was needless! the surface was absolutely smooth and one with eyes shut couldn't tell if it's a molded shape or consist of layers. but this was not a horn. it's was a preset template of Artcam. NowI want to do this with a real horn shape. the Z axis of our machine can move ~160mm if the dust cap is removed so a horn with 12" length could be built in two different parts and there will be a little bit of sanding just between them. I can also do this process on two pieces of hard wood. it's cheap here. just imagine how beautiful it will be the result of such method would be a very precise geometric shape. I think for making a Elliptical 3D horn I should draw a front view of the horn which is an ellipse. the width of this ellipse should be the "intact" calculated Tractrix flare. then I should condense the same flare for other parts of the ellipse. am I thinking correct? is there any information how to do this? any help is appreciated Edited December 25, 2014 by Arash Quote Link to comment Share on other sites More sharing options...
djk Posted December 24, 2014 Share Posted December 24, 2014 A full tractrix will give the lowest Fc for a given size, but is best for midrange only. An initial conical expansion with a tractrix mouth will be useable as a two-way. I will have to give some thought as to what the best transition point (conical to tractrix) would be. 1 Quote Link to comment Share on other sites More sharing options...
Arash Posted December 24, 2014 Author Share Posted December 24, 2014 A full tractrix will give the lowest Fc for a given size, but is best for midrange only. An initial conical expansion with a tractrix mouth will be useable as a two-way. I will have to give some thought as to what the best transition point (conical to tractrix) would be. is there anywhere in the forum any information about elliptical horn with a conical start and a tractrix ending? that would be very hard in calculation point of view. any calculator? Dave's Eliptrac works near perfect as a two way so that should be also a horn with conical throat? Quote Link to comment Share on other sites More sharing options...
Arash Posted December 24, 2014 Author Share Posted December 24, 2014 (edited) this is what I ended up tomorrow: profile: pure Tractrix cutoff frequency: 310hz Edited December 26, 2014 by Arash Quote Link to comment Share on other sites More sharing options...
seti Posted December 25, 2014 Share Posted December 25, 2014 Wow! Beautiful work as always. Would love to see it out of solid wood. 1 Quote Link to comment Share on other sites More sharing options...
djk Posted January 6, 2015 Share Posted January 6, 2015 "Dave's Eliptrac works near perfect as a two way" IMO, the dispersion is inadequate at HF. 1 Quote Link to comment Share on other sites More sharing options...
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