Multicell horns

All right... multi-cell horns are one of the coolest thing Ive ever seen.
Ive never had the chance to hear one. Are they cool but obsolete tech? Any notable advantages or disadvantages?
I noticed they are all(mostly?)exponential. Is that the only flavor they come in? Does a multi-cell version of the same horn profile sound any different? That is to say, whats the difference between a 'single cell' and say an 18 cell of the same overall size?

No project here. Just curious.

MrKramer
 
Well I love them. But some folks hate them.

To me, they are the best sounding horns. I currently use a pair of 8 cell 300Hz horns, but I think the 10 or 15 cell 500Hz horns are better for most uses.
 

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Cal, I'll see your 20 pound Alnico 288 and raise it a 31 pound ferrite 291!
But you'll always have 20 more cells than me. 🙂

What is it you like about your 8 cell?

Well.... the first thing I liked about them is that they were affordable. I got them for about 1/4 the price that a typical 15 cell pair goes for. That was the major factor.

But the 8 cell horn does have some advantages. It has a very tight pattern, which keeps the sound from splashing off the walls. Maybe too much, in my room. The pattern is stated as 35ºVx70ºH. That's pretty tight. By comparison, Cal's 1803s are given as 53ºVx105ºH. The 15 cell horns are similar.

(warning, what follows is opinion and experience only, I have no cold, hard facts to back it up).

The reason I like the multi-cell horns is that they sound the most natural to me. There are a lot of both good and bad horns out there, but the multi-cell are the most natural sounding to me. With the right driver and crossover - they sound like real music, played by real people in a real space. And that's my goal.

What the multi-cell horns are supposed to do is break up the sound into a lot of little horns - 8, 10, 15, 18 - to give a more uniform wavefront. Large horns tend to beam, I.E. they don't have an even FR across the pattern. The center tends to be "hot" and the highs drop off toward the edges.
But by breaking this up into a number of smaller horns, each will have more uniform coverage. Combining many of these into a bunch allow the horn to play at much lower frequencies than any of the individual parts can. Similar to a line array.

The objection to the multi-cell horns is that the sections interfere and cause comb filtering. If they do, I have not heard it, nor have I ever had anyone stand in front of a pair of multis and complain about it. If it does happen, it does not seem to be very objectionable to the ear.

Why aren't they made anymore? (outside custom projects). Cost and size, most likely. They are expensive to build and transport. They are huge. Companies are always looking for ways to cut costs and still maintain "good enough". I think that the multi-cell horn fell prey to that.

But I love them. Once heard, there was no turning back.
 
That "man cave" painting is really cool. I'm jealous!
And Cal, nobody told me multicell horns double as a place to set your beer. This just keeps getting better.

I can see what you mean about why they are not seen so much these days. 'Big, heavy, expensive to make' pretty much dooms anything it seems.
On the other hand, big-real-natural sounds fantastic to me.

MrKramer
 
Hi there,

although based on a completely different principle,
those remind me on the acoustic lens used by Harold Beveridge
in his famous electrostatic speakers. That lens is used
to control dispersion, it is not a horn of course.

Even modern stackable horns used in line arrays make use of
sectioning to provide equal path lengths from the driver to the slit
formed mouth(s), which make up a line source when stacked.

http://www.bevaudio.com/technical/Bev_ES_reflection1.png

http://www.renkus-heinz.com/WhitePapers/LineArrays-WhitePaper.pdf

I think in those horns there is still effort in manufacturing.

The idea of sectioning a sound path to control path length and
thereby dispersion is not dead, but lives on in some recent
contructions.

But i would like to listen to those vintage Altec horns indeed ...

Kind Regards
 
Why sure! Here's some photos I've collected.

Big Western Electric bass bin and amazing multi-cell that sold on ebay recently. The horn went for $950 Never seen one like it.

Also a little multi-cell tweeter that is now on ebay.
 

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Here are the multi-cell horns I grew up listening to. There were part of the sound system at the Mountainside Theater in Cherokee, NC.

We have a 1505 and what looks like a tar filled 1005. Those tar filled horns are heavy!
 

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I'm currently doing a study of the early cinema systems and how they were involved in the formation of the cinema "X" curve.

Multicells were easy to construct without major tooling. You could also form up common cells and make a variety of horns from them: 2 x 4 cells, 3 x 5 cells, etc. They tend to have broader HF dispersion than a radial but lower treble on axis because of it. Their polar curves aren't especially smooth.

I would be especially interested in any early measurements anyone has (beamwidth, d.i., etc.)

David Smith
 
I'm currently doing a study of the early cinema systems and how they were involved in the formation of the cinema "X" curve.

Multicells were easy to construct without major tooling. You could also form up common cells and make a variety of horns from them: 2 x 4 cells, 3 x 5 cells, etc. They tend to have broader HF dispersion than a radial but lower treble on axis because of it. Their polar curves aren't especially smooth.

I would be especially interested in any early measurements anyone has (beamwidth, d.i., etc.)

David Smith

Hmm, the 'X' curve is based on the many decades of human hearing research WRT maximum speech intelligibility requirements in a reverberant sound-field. Early cinema systems used the Academy curve that addressed this and the 'noisy', limited BW film soundtracks of the day. Anyway, all this is well documented by Dolby.

Yes, the multi-cell is the original constant directivity horn. Altec published some polar and DI plots in later years which can be found at the unofficial Altec's tech papers site.

GM
 
I have these 300hz Altec 1003b multicell horns. They are tar filled and f'ing heavy. Two guys can just move these, but I think you'd need more men to carry up stairs etc.

I bought these about 6 months ago but they are too heavy to move so they've stayed on the ground floor annoying the hell out of my wife.

A new house is in my future with a nice 22x26ft dedicated home theater so I'll get to try them then.

For the moment I have Altec MR64 horns performing mid range duties.


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