The same horn as above in an infinite baffle:BTW, this is the final "2P" horn I'm going to actually build and test (640 x 476 x 340 mm, 1.5" throat): ...
The same horn as above in an infinite baffle:BTW, this is the final "2P" horn I'm going to actually build and test (640 x 476 x 340 mm, 1.5" throat): ...
Yes, from the start I've been under the impression this thread has been about the pursuit of the most theoretically perfect results attainable.Guys, this is what it has been all about for hundreds of pages of this thread already, since the dawn of the OS-SE formula
Thank you very much !Yes, you can do it with ATH. I haven't tried to optimize any but from the attempts I made it was pretty clear that it's simply worse.
This is an example with the outer dimension very similar to the horn above (free standing):
View attachment 1089272 View attachment 1089273 View attachment 1089274
Perhaps it could be further improved, I just don't know.
You can see in the simulation mabat did below and in the one's I ran before on a big conical with and without a secondary flare what you miss out on. Better smoother pattern control and less diffraction generally. What you have to ask yourself is how much do those things matter when the horn itself is big enough and point source enough. From your own experience you said didn't notice any real difference in sound between secondary flare on or off but it measured better and more consistently with it on.Because I'd love to get an idea of how much I'm leaving on the table by not striving for OS perfection for the CD, in order to gain the overall point source properties a synergy provides across a wider bandwidth (than a CD alone can cover). Thx.
Yep. You surmise my thoughts well. I guess the real motivation behind my questions/doubts is simply looking for a toehold for further improvement.You can see in the simulation mabat did below and in the one's I ran before on a big conical with and without a secondary flare what you miss out on. Better smoother pattern control and less diffraction generally. What you have to ask yourself is how much do those things matter when the horn itself is big enough and point source enough. From your own experience you said didn't notice any real difference in sound between secondary flare on or off but it measured better and more consistently with it on.
I've looked at mounting drivers to various commercial horns like bushmeister did. It's clearly viable.Only the mounting flange for the driver needs to be flat. The horn can have a slight curve without making it difficult to attach the driver but fabricating the mounts would need a CNC/3D printer or manual labour like bushmeister did with his.
...a good adapter will at least match the tangent angles of the boards perfectly. I figured out how to do it and implemented this recently but I'm not yet sure I want to make it public domain -
mabat said:
...a good adapter will at least match the tangent angles of the boards perfectly. I figured out how to do it and implemented this recently but I'm not yet sure I want to make it public domain -
I'm not sure if what your doing is exactly the same but I believe I have already posted code that does this for the joining of exponential sections to conic sections in an attempt make expoential-conic horns without wall angle discontinuity.
I think the practical difference is pretty small but there aren't really many good commercial horns to buy.I've looked at mounting drivers to various commercial horns like bushmeister did. It's clearly viable.
One downside is any curvature lengthens the ports, which begs they be a little bigger, which mucks a little more with polars. But all that still might make for a good tradeoff, vs plain straight walls.
With the power of CAD and 3D printers, why not make an adapter closely attached for the wave-guide?Some screenshots of a port design in a fairly high curvature waveguide. There is a bit more throat volume from the frustrum section but the port can be quite short.
My images were illustrative as they are the inner surfaces used for a BEM model. In a real implementation they would be cut out of a solid block made to fit the back of the waveguide as you show.Hi fluid, mark100,
With the power of CAD and 3D printers, why not make an adapter attached for the wave-guide?
Hi M, hi fluid,Hi fluid, mark100,
With the power of CAD and 3D printers, why not make an adapter closely attached for the wave-guide?
View attachment 1089959
Although this is for Aura NSW2, even bigger close fitting driver-to-wave-guide can be fashioned. And without CNC, CAD 3D printers.
View attachment 1089960
Of course, the big advantage of CAD, 3D printing is the ability to adjust the drawing parameters and re-print, if the measurement does not confirm the theory.
Kindest regards,
M
I might be mistaken, as I mostly am, but it seems to me that you are neglecting the fact that the bigger driver is further from the throat and, thus the higher rate of curvature. I am attaching an old drawing from my initial thinking about the issue. Note that the volume between the cone and the wall is increased by the volume of the injection port, which is a function of the curvature (generally along all three axes), the size of the injection port, and the diameter of the driver.I can see that can work for smaller drivers.. For larger drivers, it seems driver diameter vs any horn curvature, is going make doing so pretty tough.
The way I did it, was to mount the wave-guide on a milling-machine table. I then chucked a dial indicator into the spindle and indicated zero on, e.g., the throat. I was then raising the spindle with the dial indicator by a pre-determined delta (let us call it in z-axes), moved the table in the x/y axes, until the indicator read zero again and read the delta between the previous position and the new one.how are you able to measure and create a 3D model of the horn for off the shelf horns?
Could you please explain your response in a manner of talking to an idiot?what about continuously expanding adapters? (helmholz frequency increased), an engineered mesh could be used at the horn inner surface to 'hide' the tap from the compression driver
Hi mark100,
I might be mistaken, as I mostly am, but it seems to me that you are neglecting the fact that the bigger driver is further from the throat and, thus the higher rate of curvature. I am attaching an old drawing from my initial thinking about the issue. Note that the volume between the cone and the wall is increased by the volume of the injection port, which is a function of the curvature (generally along all three axes), the size of the injection port, and the diameter of the driver.
Once one has designed the horn/wave-guide, the injection ports size, and selected the drivers, the added volume can be calculated. In any event, should the added volume be a problem, it can be solved by fashioning a volume reducer.
I also understand, but was unable to figure out how to model it yet, there is a relationship between the under-the-cone volume and the size of the injection ports, that may mitigate the problem. Maybe fluid will know how to model/optimize it.
Kindest regards,
M
View attachment 1090148