fibre glass 511B and XO

[bfish]

There seems to be a common assumption that all CD horns must comply to EV's trademarked "Constant Directivity" principal and definition. One might consider that "Controlled Dispersion" also abbreviates to CD, applies to horns as well, and was in use long before EV wae issued the trademark. In GM's explanation, I don't see the words 'constant directivity', but I do see the words 'controlled dispersion'.

[GM]

Originally posted by RKLee:
GM: In your opinion the newer designed horns of today such as Altec's Mantaray design are superior............

<font size="2" face="Verdana, Helvetica, sans-serif">Greets!

As a general statement, yes. Conical waveguides (WG) are a big step up and what I recommend for max fidelity.

GM

[GM]

Originally posted by David Yost:
Hi, GM, All:

Here is what EV has to say about CD horns........

<font size="2" face="Verdana, Helvetica, sans-serif">Greets!

It's not any Altec I've seen a directivity plot of and the 511/811 aren't technically radials since the initial expansion is long/big enough to control the HF over a narrow angle for the 'squish' area of the expo flare to fan it out somewhat, only the 311 series meets the EV's definition AFAIK and even these don't plot that bad.

GM

[GM]

Greets!

LOL! FWIW, it wasn't really an attempt to do a 'Bill Clinton' to 'skirt' my way around EV's trademark, just that constant directivity = controlled dispersion over some portion of its BW, which the 511/811 does by design within the limitations of the driver they were designed for and that similar EQ is required.

As Earl Geddes periodically harps on, even the best horn/WG designs are compromised by poor driver design, especially those with the horn's initial flare built in, like the Altec's. W.E. got it ~right from the get-go and I guess JBL, et al had to design in various compromises to keep from being sued.

GM

[bfish]

Also LOL.

I think Monica focused her constant directivity on Bill's controlled dispersion!

Wasn't trying to put words in your mouth, GM, I got it the first time. Your "over some portion of its BW" should finally clear it up for all.

When you look at the polars of any CD horn it soon becomes apparent that none of them exhibit constant directivity over their full rated bandwidth. If they did, there'd be no need for polars at all.

[cclark65]

GM - thanks for taking the time to explain the question properly, it is VERY much appreciated!
I understand the concept now, I'll just have to go look at some of my 511's in the garage and check it out.

I have several of the small format Mantaray horns, and I love the sound of them. The only problem is I only have 4 of the 60 degree horns, and I want 8 of them! Anybody need some 511's or maybe some MRII594's to trade even up for some MRII564's? I couldn't send the 594's immediately because they are in use, but I could send them as soon as I got new midrange cabinets made to match the 60 degree pattern :-)

I'd like to run 3 or 4 horns per side at the live shows I do, but 90 degree horns overlap way too much.

[GM]

Originally posted by bfish:
Also LOL.

I think Monica focused her constant directivity on Bill's controlled dispersion!

Wasn't trying to put words in your mouth, GM, I got it the first time. Your "over some portion of its BW" should finally clear it up for all.

When you look at the polars of any CD horn it soon becomes apparent that none of them exhibit constant directivity over their full rated bandwidth. If they did, there'd be no need for polars at all.

<font size="2" face="Verdana, Helvetica, sans-serif">Greets!

Understood, I didn't mean to imply you did.

I hope so, I don't know how to explain it any better than I already have since I don't know how to do it mathematically, which is the way these were designed.

Yeah, even the best ones are pretty limited, though Geddes' foam filled one covers a much wider BW at the expense of too much efficiency for prosound use where it's needed most.

GM

[GM]

Originally posted by Charles Clark:
GM - thanks for taking the time to explain the question properly, it is VERY much appreciated!

Anybody need some 511's or maybe some MRII594's to trade even up for some MRII564's?

<font size="2" face="Verdana, Helvetica, sans-serif">Greets!

You're welcome!

Not me....

GM

[Ronald Lee]

Originally posted by GM:
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by RKLee:
GM: In your opinion the newer designed horns of today such as Altec's Mantaray design are superior............

<font size="2" face="Verdana, Helvetica, sans-serif">Greets!

As a general statement, yes. Conical waveguides (WG) are a big step up and what I recommend for max fidelity.

GM</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">It makes sense. With today's modern speaker design and sim software, excellent horn and drivers can be designed in just a few mouse clicks. In the old days, this software and the computers to run it were in the domain of engineering labs.

Personally, I'm just going to keep my ancient 811s, my speakers just wouldn't look the right if I got waveguide horns. Besides I would have do more work to modify my enclosure to mount the new horns inside the cabinet. Funny, everyone's attention is focused on woofers, but when I built my speakers, the mid horns and drivers were the most expensive part; in 1975 dollars, I know I paid somewhere in the nieghborhood $70-$80 each for a driver or horn.