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Multi-Way Conventional loudspeakers with crossovers

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Old 23rd November 2012, 04:08 PM   #651
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The joins between the cells do you mean? See photo below:
(Wow, had to take a flash photo to see how dusty it is in there!)
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Old 23rd November 2012, 04:27 PM   #652
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Yeah I meant anont the front edge.

Ah ok. The other photo must have been taken around noon with the sun shining down on them (the shadow on the ground confirms) It cast a shadow from what is a very fine difference in height according to the 2nd photo.

An genuine trick of the light!
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Old 23rd November 2012, 04:34 PM   #653
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If you look closely at the photo in post #650, you can see that the cells were joined by a metal strip that follows the edge. That's how they are held together across the width. I suppose you could use tape.
There is one top and bottom and another in the center. The center one may be easier to see.
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Old 23rd November 2012, 05:20 PM   #654
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I can confirm the measurements of the 1803 against the literature. The mouth openings are the same but I didn't realize the horn sections were longer than the 1505. I thought it was just 1 more row. Learned something today.

Also, Michael your width measure doesn't take into account the extra width at the center of the horn which according to the Altec lit., is an inch more either side. Mine measures 42" at the tabs and 44" at the center
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Old 23rd November 2012, 05:37 PM   #655
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What center?
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Old 23rd November 2012, 05:44 PM   #656
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The horn's axial length must be longer to have a lower cut-off, hence the flare frequency will be lower for a given mouth area.

Note these are all expo horns, so with the throat, mouth area + axial length, the flare frequency can be calculated, then input these values into an expo calculator to get the expansion over distance areas to make a template.

IIRC, the larger multi-cells don't have all cells the same shape, so if they are all made identical, then their polar response will be different, maybe to the point of having too wide/tall a 'sweet spot' unless a relatively close LP is used.

I wonder if the wood horns are correct in this respect.

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Old 23rd November 2012, 06:44 PM   #657
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Quote:
Originally Posted by Pano View Post
What center?
If you look at the mouth of the horn, the middle is wider than the tabs that you have measured.
Quote:
Originally Posted by GM View Post
IIRC, the larger multi-cells don't have all cells the same shape
I will go check.
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Old 23rd November 2012, 06:49 PM   #658
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All horns are identical.
All mouths are square.
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Old 23rd November 2012, 06:52 PM   #659
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Quote:
Originally Posted by Cal Weldon View Post
If you look at the mouth of the horn, the middle is wider than the tabs that you have measured.
Got it. The center line is slightly wider than the top or bottom lines, yes.
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Old 23rd November 2012, 06:58 PM   #660
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Correct, but what about the horn expansion itself? IOW, are they all ~perfectly symmetrical sighting down the center-line or do they bend with at least one side being straighter?

Another thing I just thought of is that back when Steve and I were discussing these, we were talking about the old tar filled horns. I've no experience with the Aquaplas coated units, so wonder if Altec over time did a bit more cost cutting and began using just one cell shape.

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