I don't see it that way if the point of the excercise was to get to a cone. Unless the cone fits the room something has to give somewhere. It's been suggested that a LeCleach profile is the epitome of a practical mouth beginning at the throat, but there are other compromises. Put a large enough radius on a cone and the two begin to bear similarities anyway. Pick your poison?
C-Bezier Curve Applied to Horn Design ...
... nothing more!
I discovered the C-Bezier curve while researching a design issue having nothing to do with acoustics. However, it became apparent to me while reading the paper, that it would also be useful in the layout of typical horn profiles where discontinuities in curvature were to be avoided. All I wanted to do is share that information here. Apparently, in this thread, any thing that is different is unwelcome. If someone wants to discuss usage of this curve in horn design, I will be more than happy to respond, otherwise ....
WHG
... nothing more!
I discovered the C-Bezier curve while researching a design issue having nothing to do with acoustics. However, it became apparent to me while reading the paper, that it would also be useful in the layout of typical horn profiles where discontinuities in curvature were to be avoided. All I wanted to do is share that information here. Apparently, in this thread, any thing that is different is unwelcome. If someone wants to discuss usage of this curve in horn design, I will be more than happy to respond, otherwise ....
WHG
Steve, you keep saying this, but without any support. I can show a consistent paper trail leading to my designs, but you don't seem to have anything to show except your claim. What were you doing in 1975 that was involved with horns?
Earl,
All the information I would have is hand noted mathematics that my brother was doing to solve the mathematics. There was a professor at Cal Tech involved in solving some of the math as it was not using a complete ellipse but a portion and this made the math very messy. What I was doing was that I was working in the industry around Pro Audio PA and was interested in what was going on. I had been doing PA setup and had been around all these horns for years and was interested in what was going on. I hit the books in the engineering library at UCLA and read all I could find from Webster to Klipsch, some of it made sense and some of what I read just didn't seem correct. So I started to build horns to see what was going on. It wasn't long before I went to make a radial horn and very quickly saw the error that was introduced by the connection of the throat of the horn to the horn flare. It hit me like a brick between the eyes the fudge that was used to connect the two sections. This lead me down the road to a way to correct this error and that made me wonder why there needed to be a dip where the transition was. This lead me to the concept of elliptical shape changes without causing the dip in the transition from the end of the driver to the horn flare. I actually wrote a proposal to Bayer at the time to do some joint development. I'll leave it at that in a public forum.
All the information I would have is hand noted mathematics that my brother was doing to solve the mathematics. There was a professor at Cal Tech involved in solving some of the math as it was not using a complete ellipse but a portion and this made the math very messy. What I was doing was that I was working in the industry around Pro Audio PA and was interested in what was going on. I had been doing PA setup and had been around all these horns for years and was interested in what was going on. I hit the books in the engineering library at UCLA and read all I could find from Webster to Klipsch, some of it made sense and some of what I read just didn't seem correct. So I started to build horns to see what was going on. It wasn't long before I went to make a radial horn and very quickly saw the error that was introduced by the connection of the throat of the horn to the horn flare. It hit me like a brick between the eyes the fudge that was used to connect the two sections. This lead me down the road to a way to correct this error and that made me wonder why there needed to be a dip where the transition was. This lead me to the concept of elliptical shape changes without causing the dip in the transition from the end of the driver to the horn flare. I actually wrote a proposal to Bayer at the time to do some joint development. I'll leave it at that in a public forum.
The reason that I ask is because just after my paper in 1991, I worked with just about everyone in the horn business, Peavy, JBL, Klipsch and many others, on waveguides and none of them had this idea before. Not until you made this claim yourself had I ever heard about it coming from somewhere else. It surprises me that, if you did do this work, it stayed so secret for another decade or more.
Bill
I appreciate your link to the paper, it is a fine piece of work (quite unique for the Chinese). I can't speak to its originality (a lack of which is typical of Chinese researchers) and it is clear that it could be applied to the problem at hand. That said, I have serious doubts that it would come up with anything different than what has already been found. One can, of course, speculate that it will, but that remains to be shown (and I highly doubt that it ever will be done.)
I appreciate your link to the paper, it is a fine piece of work (quite unique for the Chinese). I can't speak to its originality (a lack of which is typical of Chinese researchers) and it is clear that it could be applied to the problem at hand. That said, I have serious doubts that it would come up with anything different than what has already been found. One can, of course, speculate that it will, but that remains to be shown (and I highly doubt that it ever will be done.)
This would be typical of in house research.
Commercially, it makes sense to keep it secret.
Look at all the leavers that have to take gardening leave to protect their former employer for a period.
Accademia is quite different.
Publish and make everyone aware of how good one is by the number of papers produced over the years.
Commercially, it makes sense to keep it secret.
Look at all the leavers that have to take gardening leave to protect their former employer for a period.
Accademia is quite different.
Publish and make everyone aware of how good one is by the number of papers produced over the years.
Andrew, I forgot. Plasticine.
I stuck some the bottom of a plastic medicine bottle and stuck it in the freezer. Just took it out and it seems perhaps a little stiffer - harder to deform with my fingers. I hit it with a hammer and it deformed but no cracking or signs of brittleness.
It seemed to stick to the plastic about the same as at room temperature. It's not sticky in itself - not a glue.
I think under normal temperatures it doesn't change its characteristics. As long as it remains in intimate contact with what it's supposed to be damping it ought to work.
It's funny stuff. I think it's what's called a non-Newtonian fluid, which is beyond my pay grade.
I stuck some the bottom of a plastic medicine bottle and stuck it in the freezer. Just took it out and it seems perhaps a little stiffer - harder to deform with my fingers. I hit it with a hammer and it deformed but no cracking or signs of brittleness.
It seemed to stick to the plastic about the same as at room temperature. It's not sticky in itself - not a glue.
I think under normal temperatures it doesn't change its characteristics. As long as it remains in intimate contact with what it's supposed to be damping it ought to work.
It's funny stuff. I think it's what's called a non-Newtonian fluid, which is beyond my pay grade.
I have found that in China they are not very aware of what others around the world are doing, or more importantly, have done. They never go to overseas conferences. They never read books that aren't in English or that they actually have to buy. They almost never join societies and read their journals. They reinvent almost everything. To them there isn't a world beyond the borders.
Now, of course, this is changing slowly, as they become more affluent, travel abroad more, improve their English skills, go to foreign universities, etc. I am speaking more from my experiences about a decade ago and prior.
My uncle purchased a pair of Chinese made dirt bikes around ten years ago, one of which I was riding when an axle bolt sheared, and I stopped before something nasty happened.
I was disgusted, that while these people were clearly more than 100 years behind us in technology, they didn't seem to know or care what would come of it. I've seen little since to change my mind.
I was disgusted, that while these people were clearly more than 100 years behind us in technology, they didn't seem to know or care what would come of it. I've seen little since to change my mind.
Earl,
Yes I could have if I had wanted to beat you to the patent office by quit a few years it seems. That takes nothing away from what you did, and as I have said your skills at writing a paper are far beyond anything I could have written. Your mathematical skills are worlds above mine, I just intuitively saw what you did through your education. I guess if I hadn't gotten sidetracked into doing other basic research in the plastics field I would have finished what I started but soon realized in the beginning that I just didn't have the money to seriously market a product like that against companies like JBL and others. I did speak with Mr. Peavey early on in their development and I know that some of my ideas influenced the first series of JBL EON speaker. I tried to interest them in some horn ideas and also molded enclosures but they just wouldn't pay the cost for a molded RIM urethane material, they went the route of structural foam which was much less money though it was inferior. They did have some horn samples from me that took a year to recover out of engineering. I really did keep my hands into audio all along as it was something I really loved and enjoyed but it wasn't what was paying the bills. I've been involved in solar panels with Arco, missile development with General Dynamics and Hercules, and some very advanced composites development that is only now getting to market over 25 years later. I was making housings for capacitive touch screens 30 years ago. As I said I got sidetracked and you showed the world what I had in mind in your patents. It looks like back into aerospace for me again it seems. I have two companies after me now, one is Scaled Composites out in the Mojave desert, working on the largest wingspan plane in the world or some work for another company that does interiors for planes. Got to pay the bills and these are the things that I have learned during my R&D years operating a very unique plastics company for many years now.
Yes I could have if I had wanted to beat you to the patent office by quit a few years it seems. That takes nothing away from what you did, and as I have said your skills at writing a paper are far beyond anything I could have written. Your mathematical skills are worlds above mine, I just intuitively saw what you did through your education. I guess if I hadn't gotten sidetracked into doing other basic research in the plastics field I would have finished what I started but soon realized in the beginning that I just didn't have the money to seriously market a product like that against companies like JBL and others. I did speak with Mr. Peavey early on in their development and I know that some of my ideas influenced the first series of JBL EON speaker. I tried to interest them in some horn ideas and also molded enclosures but they just wouldn't pay the cost for a molded RIM urethane material, they went the route of structural foam which was much less money though it was inferior. They did have some horn samples from me that took a year to recover out of engineering. I really did keep my hands into audio all along as it was something I really loved and enjoyed but it wasn't what was paying the bills. I've been involved in solar panels with Arco, missile development with General Dynamics and Hercules, and some very advanced composites development that is only now getting to market over 25 years later. I was making housings for capacitive touch screens 30 years ago. As I said I got sidetracked and you showed the world what I had in mind in your patents. It looks like back into aerospace for me again it seems. I have two companies after me now, one is Scaled Composites out in the Mojave desert, working on the largest wingspan plane in the world or some work for another company that does interiors for planes. Got to pay the bills and these are the things that I have learned during my R&D years operating a very unique plastics company for many years now.
Issues ...
... Geometric
There is prior art on this curve, but this paper was my initial find. It provides the necessary information for it to be used for lofting horn profiles, particularly throat adapters and mouth bell segments. As such, it is just a tool that I plan on implementing in Excel VBA and AutoCAD. Of course it is not a substitute for understanding the underlying acoustics problems that need to addressed during horn design. However, with this tool in place, the issue of curvature continuity is no longer one of them.
... Oriental
Here is a fact to ponder at the moment: not a day goes by that we are not exposed to the message, "Made in China".
WHG
... Geometric
There is prior art on this curve, but this paper was my initial find. It provides the necessary information for it to be used for lofting horn profiles, particularly throat adapters and mouth bell segments. As such, it is just a tool that I plan on implementing in Excel VBA and AutoCAD. Of course it is not a substitute for understanding the underlying acoustics problems that need to addressed during horn design. However, with this tool in place, the issue of curvature continuity is no longer one of them.
... Oriental
Here is a fact to ponder at the moment: not a day goes by that we are not exposed to the message, "Made in China".
WHG
WHG,
I still think your blowing the curvature of this short section way out of proportion to the final results. If you have played with something like a typical hyperbolic curvature in a horn and looked at how that changes the final result you will see that slight changes in curvature don't change anything more than slightly. You are trying to make a smooth transition from one angle to another with tangent angles at both ends and the shortest transition zone as possible if you are after the most constant directivity possible, if that is your end goal.
The C-bezier curve is interesting for other transitions such as between multiple intermediate curves but I don't see it being as important in the transition zone between two purely conic sections. There is more diffraction inside the compression driver at the joints of the phasing plug and the throat section than anywhere else in the rest of the horn section. This is where the real improvements could be made but since nobody is building diy compression drivers I think you are making a mountain out of a mole hill here.
I still think your blowing the curvature of this short section way out of proportion to the final results. If you have played with something like a typical hyperbolic curvature in a horn and looked at how that changes the final result you will see that slight changes in curvature don't change anything more than slightly. You are trying to make a smooth transition from one angle to another with tangent angles at both ends and the shortest transition zone as possible if you are after the most constant directivity possible, if that is your end goal.
The C-bezier curve is interesting for other transitions such as between multiple intermediate curves but I don't see it being as important in the transition zone between two purely conic sections. There is more diffraction inside the compression driver at the joints of the phasing plug and the throat section than anywhere else in the rest of the horn section. This is where the real improvements could be made but since nobody is building diy compression drivers I think you are making a mountain out of a mole hill here.
JCX,
yes with 3d printing with photo polymers you could make a new phase plug section. Take something like a Radian driver and knock out the phase plug and replace it with a newer center section and you could possibly create an improved driver. There is also 3D metal parts but that is much less common for all but a few companies.
yes with 3d printing with photo polymers you could make a new phase plug section. Take something like a Radian driver and knock out the phase plug and replace it with a newer center section and you could possibly create an improved driver. There is also 3D metal parts but that is much less common for all but a few companies.