Wooden 511

[cclark65]

I would bet that if you left the outside of the block alone, just milled out the inside, it would be fine. Removing the mounting flange from a metal horn might make it ring even more than they do already. However, I am thinking that the outside of the horn will not really matter, and probably leave it just a large square block.
For durability on the wood horn, you might want to make it without the vains, and cut some grooves in them to slide in some made out of masonite or something similar.

[Datubie]

How about trying to mill a 329A? The vanes (well, they are rods actually) are removable. Good luck finding one though.

[djnagle]

GM, the coolest looking horn I have ever seen is the 1505. It won't hurt to bring it up when I meet with the machine shop. I'll let you know.

[megalon]

I'm local to you and I would love to have a pair of these someday. Right now things are check to check but I hope that will change in the near future (don't we all).

If I am able to swing for a pair of these, I'll make sure to throw you some cash to offset your initial investment.

The E-bay possibilities are phenominal!

[Steve Schell]

Hi Igor,

Having a wooden 511 CNC machined certainly sounds like an ambitious project. I wonder, though, if it might not be possible to make some equal or superior horns through simpler and cheaper means. Rather than copy the 511 flare exactly, why not design some radial horns from scratch? I have calculated and built radial horns in the past, and can help you with the math (though I'm certainly no whiz). I also have reservations about the initial throat section of the 511. It is quite constricted, and appears to have been designed to create a narrow on axis high frequency beam. The high frequency hot spot has always sounded unnatural to me, but you could lessen or eliminate this with a fresh design. You would also have complete freedom to choose cutoff frequency and horizontal pattern. Constructing the horns from several pieces of wood glued up after shaping might be an easier construction method, while offering all the benefits of using wood. Just my wooden 2 cents...

[dstamand]

511 hotspot - interesting. Does anyone have a link to a Frequency Response graph that shows this hot spot?

Dwight

[dhook17322]

Two points on the wooden 511:
Seems like it would be far easier to digitize one half of the horn and make it from two sides bonded together. The wood block size would be smaller and the digitizing and machining time would be much less. It would also easily present the option of making them a 511E to accomodate a large format driver if someone wanted one. Unfortunately it would require slicing a metal one, but they're very common on ebay.
A design problem at the rear mounting flange exists as a thin wooden flange will quickly break out. Some sort of mounting adapter using threaded inserts in the wood would have to be designed, especially if a 511E were the objective.

[djnagle]

Dave, I have not met with the CMM guy yet (end of this week) but I would imagine that he would only have to digitize 1/4 of the horn, then flip it left to right and top to bottom. The five axis CNC milling machine does not care if it two halfs or one piece. As for the outside of the horn, we are just going to draw a line from the outside of the front of the horn to the round flang and call it good. Cheers.

[Todd W. White]

The Altec 511's & 811's were cast in halves, hten assembled.

The vanes were added later to give strength and (supposedly) added directivity. There also used to be a smaller brace way back in the flare near the throat itself, which Altec stopped installing in later years, even though the casting allows for it.

I like the idea of a more solid horn, although I think a wooden one would be too expensive unless you could get the cost down.

I also like the idea of a totally new horn - Jim Dickinson and I have talked about having Jerry Hubbard design a new series of horn: he's already got big Mantaray's done, so small sectorals using the Mantaray concept might be really well behaved...

[thevott]

The 511 is an excellent horn and a wood version will be fabulous. I do agree, however, with Steve and Todd that a fresh design might be the ticket. I would personally like to have a 60? (horizontal) version and, yes, the 511 does have a narrower dispersion at its highest frequencies. Also, if you keep your eye out on ebay 511s and 811s sometimes sell for under $50. for that price you can hack one up without remorse.

PS: The vanes, in my humble opinion, being perpendicular to the wave front are structural only though they undoubtedly have some affect on the sound. I have an idea! Lets cut-em out of one horn and mail the thing around to everyone interested. We can then all do an A to B test and settle this thing once and for all. If ten people split the cost of one horn plus shipping cost to the next person it should be only $20-$30 each