1803B horn plans available?

[Audiomind]

Of course I'm assuming the vertical members are the same as the horizontal ones. If the opening is square, it should be...no?

Or maybe someone that owns one can trace the outline and scan it. Size doesn't matter, it can be printed to scale.

I fear that execution of the build will factor more into the final result than the starting plans. Making 18, no 36 identical cells will be more of a challenge than the calculus. I would think jigs should be utilized.

As I mentioned it is not a linear expansion like a conical and the center cell mouths are slightly different than the top and bottom cells plus the termination of the cells near the throat adapter are not really a straight line either.

I don't think a jig is needed for one pair of horns but having the few different template fins would be needed.

Even if I did have an original 1803B horn available near by me in North Florida it would take some time to make template paper of the cells, trace the throat adapter and take enough measurements of the throat adapter with machine machine shop measuring tool tools to make a relevant drawing..........

Ugghh...that is why I was hoping to get the plans, it is going to take enough tine to build it without having to design it again.

Alan, if you are building multicells and spending and have a shop available why not build the king of multicells 1803B forget the lesser smaller sounding puny horns and have the voice of God in your living room....just joking don't want to get any spouses on my case about convincing anyone to make a pair of these monsters. I am building mine for a high end nightclub with the space and distance needed for these.

For anyone that has not heard a large 250-300hz multicell I would suggest you hear one on a good playback system if you ever get the chance, they really do something that no other horns seem to do and may open your mind about what is possible with audio, a real treat, even if you are not aloud to bring them home.

[alancohen]

Alan, if you are building multicells and spending and have a shop available why not build the king of multicells 1803B forget the lesser smaller sounding puny horns and have the voice of God in your living room....just joking don't want to get any spouses on my case about convincing anyone to make a pair of these monsters. I am building mine for a high end nightclub with the space and distance needed for these.

No spouse to be concerned with, but they're just too big.

[GM]

I would have to get the measurements all the way down the cell and not just the mouth exit.

Plug the length, throat and mouth area into Hornresp and it will calculate the expo flare frequency and then you can download all the details to build it either round, square, rectangular and choose the increment distance. Read the HELP file for all the particulars.

GM

[Audiomind]

No spouse to be concerned with, but they're just too big.

Not to stray too far off topic on my own thread but besides beside the 1803B being too big for most homes, the other issue with the 1803B and any of the other multicells that don't allow you to "see" down the center to the driver will get really annoying after a while.

This is not a problem for pa as I am using it but in home use it bugged me quite a bit. Personally I could not live with the 805 or any other multicell in a home setting that you can't see down the center cell to the driver, sounds like you are driving by a guardrail in a car if you move your head even slightly.

The 1505B allows you to see down the center for a better image and larger sweet spot. It is slightly taller than the 805B and has the same 500hz cutoff. The 1505B always looked more balanced to me than any of the non square multi cells, with only one more cell row and it really is sort of comparable in size to 805B but no where near the monster of the 1803B.

So anyway just wondering why not the 1505 for you?

[Audiomind]

Plug the length, throat and mouth area into Hornresp and it will calculate the expo flare frequency and then you can download all the details to build it either round, square, rectangular and choose the increment distance. Read the HELP file for all the particulars.

GM

Yes this is probably what I will end up doing. It will be interesting to see if Altec stayed true to the exponential flare or did anything different.

Although if I am going through all that trouble with Hornresp I may as well design a 250hz horn that you
can see the driver down the center....and I wanted to keep this easy! not!

[valhallax]

i listen to 1505's at home all the time, they sound like pure surround sound. i also have 803's.. and like the tonal quality of the 300 hz horns better. so why couldnt one establish the flare from say a 203,803,1003 and copy the horn flare 18 times? for what its worth, the 1003's and 803's are the same flare, not different in the middle

[Audiomind]

i listen to 1505's at home all the time, they sound like pure surround sound. i also have 803's.. and like the tonal quality of the 300 hz horns better. so why couldnt one establish the flare from say a 203,803,1003 and copy the horn flare 18 times? for what its worth, the 1003's and 803's are the same flare, not different in the middle

You are losing me a little but I am interested in understand what you are saying.

1. I am guessing you like the 1505B having the surround sound effect with two speakers? (I do)

2. Yes the bigger horn covers much closer the holy grail of 300-3000 that the phone company
discovered was critical for intelligibility way back in the earliest days of sound reproduction hence
the much more natural tone and ease of matching up to those loafing along woofers.

3. What is a 203,803,1003? (too long to be a patent).

4. Just adding more cells to a 1003 will change the flare rate. Now I have never seen 1003
and 1803 next to each other are the cells the same size?

[alancohen]

Not to stray too far off topic on my own thread but besides beside the 1803B being too big for most homes, the other issue with the 1803B and any of the other multicells that don't allow you to "see" down the center to the driver will get really annoying after a while.

It would seem to me that having a centered cell right down the middle would make it sound more directional. Is there any empirical data to support the claim that the sweet spot is larger with this configuration?

I think I would make a "1205". The 1005 is still just too wide for me, but I don't mind going a little higher. My room is long and narrow. Is the dispersion of a 1005 wider than an 805? If so, might hurt more than help in my application.

The more I look at this, I don't think this would be a difficult build. Any thoughts about wood selection? I think stiffness would be at a premium. I'm thinking 3/16" aircraft ply like this: FINNISH BIRCH AIRCRAFT PLYWOOD (METRIC) from Aircraft Spruce . I like that it jumps from 5 to 10 ply from 1/8 to 3/16". 1/4" would be too thick. The extra plys would help maintain stiffness at the throat end where the walls would have to be very thin.



BTW, here's a pair just up for sale: http://www.ebay.com/itm/2-Altec-Lans...item2ec5d4e3d7

[Audiomind]

It would seem to me that having a centered cell right down the middle would make it sound more directional. Is there any empirical data to support the claim that the sweet spot is larger with this configuration?

I saw some polar plots years ago on the multicells and yes the higher you go the more defined the fingers look coming out of the cells. But put it this way without seeing the driver in the center cell there is no sweet spot and image is gone especially up high, at least that is what I heard.


I think I would make a "1205". The 1005 is still just too wide for me, but I don't mind going a little higher. My room is long and narrow. Is the dispersion of a 1005 wider than an 805? If so, might hurt more than help in my application.

Not sure what a 1205 is and I didn't see it on the Altec multicell chart I have, did you mean 1505B?

The more I look at this, I don't think this would be a difficult build. Any thoughts about wood selection? I think stiffness would be at a premium. I'm thinking 3/16" aircraft ply like this:
(had to remove link because you can't post links if your account is less than 3 days old)
. I like that it jumps from 5 to 10 ply from 1/8 to 3/16". 1/4" would be too thick. The extra plys would help maintain stiffness at the throat end where the walls would have to be very thin.

Thanks for the link to the aircraft plywood on you previous reply, don't know if I will use it but very cool! Didn't even know they sold stuff like that, I might need it for other projects though.

[martyh45]

FWIW, getting the “airplane wing” shape is not that hard once you have plotted the interior curves for the individual cells. First, you build the individual cells with a consistent wall thickness. Next, you the build the vertical sections. The first step in building the vertical section is to lapp the cells so you get to zero thickness on both entry and exit sides. For each vertical section you would lapp two opposite sides of one cell for the center and one side of two others for top and bottom. The next step is to glue the individual vertical sections together and let them dry.
Now that you have the vertical sections assembled you lap them so they fit together in the horizontal plane. In the case of the 1803, lay each assembled section of three on the lapping surface and remove just enough material so all four corners zero out. After you have done that you can assemble the required number of vertical sections together to complete the multicell portion of the horn.
Simple really, all you need is more time than money and a bit of hand eye coordination.