Re: Concave or Convex
the problem, as I see it, with your picture and the one that Illusus showed on the link he provided is that it does not take advantave of the concave curve. Instead one is straight and the other is convex, which does a less than perfect job of deflecting the sound waves at a lower angle.
And I am not saying that these are not necessary, because the picture above has given me another idea about how to embed the tweater and cover it with a smaller reflecter that will go with the entire effect. I like that idea, and will allow me to have more to work with, other than compression horns. So please keep the suggestions coming forward. Believe me, I take them all into consideration and beat them about in the evening before sleep overtakes me.
I'm still at the stage of lying in bed unable to go to sleep for at least one hour over this situation, and I am still coming up with the turned wooden horn like that of the Duevel speakers as being the best bet at this point. And they also look a bit more pleasing to me. But I can't say what others think.
Also a six sided enclosure has a lot of straight lines that could stand being broken up with some curves. That is why I intend to use a roundover bit on the base also.
I'm even trying to think of a way to still make a hexagon enclosure but round the corners, making them smoother over all, but I don't know how to easily apply the veneer for that much of an extended surface without coming to an end somewhere on the cabinet. On something like that, I may have to be forced to go with the book stitched sheets that are 48 inches wide, and then use contact cement to affix them to the walls.
BTY, I have a more than fertile mind...........still 😀
pblossom said:
the problem, as I see it, with your picture and the one that Illusus showed on the link he provided is that it does not take advantave of the concave curve. Instead one is straight and the other is convex, which does a less than perfect job of deflecting the sound waves at a lower angle.
An externally hosted image should be here but it was not working when we last tested it.
And I am not saying that these are not necessary, because the picture above has given me another idea about how to embed the tweater and cover it with a smaller reflecter that will go with the entire effect. I like that idea, and will allow me to have more to work with, other than compression horns. So please keep the suggestions coming forward. Believe me, I take them all into consideration and beat them about in the evening before sleep overtakes me.
I'm still at the stage of lying in bed unable to go to sleep for at least one hour over this situation, and I am still coming up with the turned wooden horn like that of the Duevel speakers as being the best bet at this point. And they also look a bit more pleasing to me. But I can't say what others think.
Also a six sided enclosure has a lot of straight lines that could stand being broken up with some curves. That is why I intend to use a roundover bit on the base also.
I'm even trying to think of a way to still make a hexagon enclosure but round the corners, making them smoother over all, but I don't know how to easily apply the veneer for that much of an extended surface without coming to an end somewhere on the cabinet. On something like that, I may have to be forced to go with the book stitched sheets that are 48 inches wide, and then use contact cement to affix them to the walls.
BTY, I have a more than fertile mind...........still 😀
If you want round you can try sonotubes, check out passdiy.com and scroll down to the sub woofers to see a very huge pair. Sonotube comes in various sizes so you should be able to find the diamater that suits your purpose.
germpod said:
Germpod, I am not sure how a sonotube is going to do the job for me. Perhaps you can explain further. Granted I need a 13" diameter round size at one point, but the rest of the horm will have to be shaped, the bottom to a point.
Please go back and read the first post in thread, if you have not already, and you will see what I am talking about. If you see what I mean, you may be able to give me more advice, ok?
Sorry - getting back to the reflector... I noticed that Linkwitz doesn't use a reflector for his Pluto design (http://www.linkwitzlab.com/Pluto/intro.htm). He kept the crossover low (1 KHz) and used active equalization for the woofer to accomodate the rising response of the driver in the enclosure. After looking at his measurements of the woofer I'm wondering if a reflector is even needed (see http://www.linkwitzlab.com/Pluto/electronics.htm). Maybe you need to put the B20s in the boxes and measure them before going crazy trying to build a complex reflector!
The idea of a deflector, on your previous post, is a good one for using as a guide to constructing a usable form for pouring. If push comes to shove, I will get it and try to see how I can make that work.
As for the Pluto, it is a nice little set up, but I am not looking for something that works best in a small room. And also, the dispersion of the sound doesn't redirect the sound waves as well as the diffraction horn I am attempting to produce.
Why do you think me trying to pay close attention to detail as "going crazy"? I don't understand this. I'm not a master woodworker, but I know enough about woodworking not to be overwhelmed by the project. And isn't trying to come up with the best possible worth shooting for? No offense, but I am really puzzled.
As for the Pluto, it is a nice little set up, but I am not looking for something that works best in a small room. And also, the dispersion of the sound doesn't redirect the sound waves as well as the diffraction horn I am attempting to produce.
holdent said:
Why do you think me trying to pay close attention to detail as "going crazy"? I don't understand this. I'm not a master woodworker, but I know enough about woodworking not to be overwhelmed by the project. And isn't trying to come up with the best possible worth shooting for? No offense, but I am really puzzled.
A really silly idea, but maybe find a really big funnel, like the biggest size kitchen funnel or one for putting oil in a car, cut off what you don't need, damp the inside and veneer the outside.
Kenai
Kenai
Kensai said:
Funny you should mention that. I have gone scouring around Raleigh, in a kitchen supply store, Wal-Mart, K-Mart, and some other places, but nothing that approaches that of 13 inches in diameter.
Amazon has a great deal of funnels, but they don't work either.
Sorry - wasn't trying to imply that getting the details right wasn't worth the effort. Just suggesting that you might want to try simple test solutions before investing the time and expense turning out a complex shape on a lathe. 🙂
Ted
casting material
John, I was just re-reading through your thread and thought of another casting material you might want to consider...casting epoxies. Although I haven't seen any audio projects using them, they might offer a couple of advantages over plaster. In particular, they should be quite a bit more durable. My experience with them is limited to casting a Journey (the band) logo in 8th grade shop class (ahh ,1981).
You can check out ETI's web page for some more info.
ETI
Just to be clear, ETI was the first google result that looked promising. I don't know anything else about them.
Squib
John, I was just re-reading through your thread and thought of another casting material you might want to consider...casting epoxies. Although I haven't seen any audio projects using them, they might offer a couple of advantages over plaster. In particular, they should be quite a bit more durable. My experience with them is limited to casting a Journey (the band) logo in 8th grade shop class (ahh ,1981).
You can check out ETI's web page for some more info.
ETI
Just to be clear, ETI was the first google result that looked promising. I don't know anything else about them.
Squib
John, look here:
Roundtree Acoustics Omni
Just an interesting thought of how to get the omni without the reflector. Kinda defeats the purpose of the B20 as its backside radiation has a much more limited top end, but I thought you might be interested to see this configuration.
Kensai
Roundtree Acoustics Omni
Just an interesting thought of how to get the omni without the reflector. Kinda defeats the purpose of the B20 as its backside radiation has a much more limited top end, but I thought you might be interested to see this configuration.
Kensai
...and then there is Duevel Planets by Urban Fidelity from Germany @ $1,295 per pair
An externally hosted image should be here but it was not working when we last tested it.
...or the BeoLab5...
An externally hosted image should be here but it was not working when we last tested it.
Kensai said:
That is really interesting. Note how the main driver is placed. And also read the specs. If you go near the bottom of the spec sheet, you will notice that the base driver is tuned by a transmission line enclosure. And also look at the driver's orientation. It is firing into the transmission line cabinet, not the other way. Fascinating application.
I suspect the TL enclosure is working harder than the infinite baffle/open aire effect of the back of the driver, I could be wrong. Also, it's horizontal dispersion is 360 degrees, and the tweat is only 90 degrees. I suppose the low end is eminating out of the base of the cabinet.
The concept of firing INTO a TL enclosure is worth investigating here. I wonder how the 7" main driver sounds?
Incidentially, I located a local lathe instructor, who teaches classes on how to use the wood lathe. I am going to take his class Saturday, at his shop, and I should be able to pick up how to use it then. He also told me that I could have access to his shop, when he was there, of course. I'll have to wait and see how well it goes Saturday. The class is $85, and should be worth every penny.
I have a neat idea on how to make a custom dispersion horn for the top of the cabinet and also drill out the top, insert a high frequency driver, and drop in another smaller dispersion horn on top of it. and I think I can make it look far better than Duevel does with their high compression horn.
Ed LaFontaine said:
right Ed. Duevel is the same company I got the origional idea from. The Planets is their bottom unit, with the Jupitor being their premier enclosures. If you go to their site, you can see all that they do.
germpod said:
No problem, you will eventually get over it. Just don't pay any attention to the smell. 😀
Well then, try this one.
That's right, speakers using the same principle. NACSound Sonance Speakers
An externally hosted image should be here but it was not working when we last tested it.
That's right, speakers using the same principle. NACSound Sonance Speakers
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