1803B horn plans available?

[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?

[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.

[Audiomind]

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.

Having seen a few different build pics I would say it is well within my capabilities, and yes simple, that is if I had the dimensions, looks kind of fun actually......now back to getting those pesky dimensions....

After doing a little research on the Hornresp program I really want to copy a factory horn as
several people had commented that Hornresp is only a starting place and does not really tell
you how the horn will sound.

I would imagine the factory design probably had quite a few tweaking hours on the design that only comes from listening......and tweaking...and listening...etc. darn I kind of wanted that 250hz cutoff 15 cell with the driver throat visible in the center..hmm sounds like a Vitavox might fit that description but then I wonder if it would like the Altec 290 I am going to be using as much as an Altec horn??!!!!!..........can I win here? Big 15 cell Vitavox horns with Altec drivers any one here tried it? Love to hear about it if so.

[cradeldorf]

Maybe the people who sell them on ebay have some info on building them. They might not be willing to share but its worth asking.
15 Cell Multicell Horns for JBL Beyma Altec | eBay

[GM]

After doing a little research on the Hornresp program I really want to copy a factory horn as
several people had commented that Hornresp is only a starting place and does not really tell
you how the horn will sound.

True, but expo is expo and for sure the 805 is pure expo and I was told by those who should know that all the Lansing/Altec multi-cells are expo, though at least the 18 cells have different shapes to get the desired polar response. The 'magic' is in the terminations and adapters.

GM

[GM]

The 1505B allows you to see down the center for a better image and larger sweet spot.

Hmm, as a general rule for HIFI/HT, rising on axis speakers should be toe'd in, including multi-cells, so using 'looking down the throat' as a primary design criteria makes no sense to me. The biggest problem with the large multi-cells is one normally can't sit far enough away for the cells to blend to a reasonable size point source in the HF.

I had 805s for awhile and toe'd in they provided the kind of 'tight' pattern control its design implied. The 1005 has a wider horizontal 'sweet spot' and the 1505 has an even wider horizontal and vertical one, just as they're size/shape implies, so contrary to popular theory, the closer one sits and/or the wider the 'sweet spot' desired, the larger the horn needs to be.

My room at the time was quite large with a ~28 ft listening distance [Lp], so the 805 was ~ideal. My current room/LP ~ideally needs stacked 805s, so not going to happen. If I build anything, it will be a DSL Synergy concept horn to get both the low cut-off and desired pattern.

GM

[Audiomind]

Hmm, as a general rule for HIFI/HT, rising on axis speakers should be toe'd in, including multi-cells, so using 'looking down the throat' as a primary design criteria makes no sense to me. The biggest problem with the large multi-cells is one normally can't sit far enough away for the cells to blend to a reasonable size point source in the HF.

Not sure if I am understanding you but in my experience aren't we not continually fighting a "sinking" response with compression drivers? *especially those on big horns.


I had 805s for awhile and toe'd in they provided the kind of 'tight' pattern control its design implied. The 1005 has a wider horizontal 'sweet spot' and the 1505 has an even wider horizontal and vertical one, just as they're size/shape implies, so contrary to popular theory, the closer one sits and/or the wider the 'sweet spot' desired, the larger the horn needs to be.

Myself I kind of chuckle when I see anyone using any multi cells close up in a small living room, it is kind of torturous to me. When I finally kicked the multi cells out of my living room for good, I brought my remaining pair and a split 210 box to store at a buddies warehouse until they were sold.

Now at 30 feet+ as you say, it was ideal, everything blends as it was intended and actually it was freakin' amazing, stunning, huge sounding and got me thinking about getting a warehouse of my own........just to listen to multi cells and bass horns(and do other cool stuff in of course, like build more giant speakers)

My room at the time was quite large with a ~28 ft listening distance [Lp], so the 805 was ~ideal. My current room/LP ~ideally needs stacked 805s, so not going to happen. If I build anything, it will be a DSL Synergy concept horn to get both the low cut-off and desired pattern.

Heard Nick McKinney's Unity horn crossed from his way good 15" Lambda driver at around 300hz. It seemed to be quite a tweaky system to get right but when it was dialed in was way better than I expected. Had unfamiliar music playing but I remember the sound was huge, open and shocking that such a weird looking pile of crap could sound so amazing. (This was over 10 years ago now so at the time not many had ever seen this concept including myself so the unfinished prototype just looked like crap pieced together).

I would like to hear the some of the new Danley Synergy version's for sure again to hear if is as good as I remember and if the extra lower horn loading brings any improvements. I still think horns like the 1803 will always sound good no matter what comes next though. Kind of like some old race cars still going fast as hell even though some newer cars are technically faster around the track


GM

Have you heard the Synergy?

[mah]

Some inspirational pics.

CH1505WBWL