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Multi-Way Conventional loudspeakers with crossovers

Pseudo-coaxial with narrow directivity (and Horbach-Keele filters)
Pseudo-coaxial with narrow directivity (and Horbach-Keele filters)
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Old 21st December 2015, 08:27 PM   #11
kessito is offline kessito  Netherlands
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Nicely done!
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Old 22nd December 2015, 12:22 AM   #12
ewollowe is offline ewollowe  Australia
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Does anyone know of any more examples of this type of design?
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Old 22nd December 2015, 07:38 AM   #13
FoLLgoTT is offline FoLLgoTT  Germany
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Quote:
Originally Posted by ewollowe View Post
Does anyone know of any more examples of this type of design?
I don't know any.

It is a 2D version of Horbach's and Keele's design. But they never showed a version with a constant directivity in the highs. The tweeter is always the problem, because it is alone and has no partner. And its bandwidth is higher than the other ways.
When doing 1D with waveguide the distance between the mid-high-drivers is too large. It doesn't work. So I switched to 2D and increased the grid depth of the mid-high-drivers to shift side lobes to higher frequencies.

I failed to design a pseudo-coaxial speaker that has a wider directivity. And I failed to design one with different horizontal and vertical directivities.

But I tried to separate horizontal and vertical with a ribbon driver and a horizontal waveguide. It doesn't work that good, because ribbons can not be crossed deep enough. And plane wave formers for compression drivers are usually too large. But the concept could still be promising.
Read the documentation here (again in German).
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Old 22nd December 2015, 07:47 AM   #14
Flaesh is offline Flaesh  Russian Federation
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Slide 21 in Horbach-Keele Presentation Part 2 V4.pdf:
Quote:
"What Do You Do With the Single Central
Tweeter at High Frequencies?
Or……..You can
use a directional
tweeter!"
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Old 22nd December 2015, 07:53 AM   #15
FoLLgoTT is offline FoLLgoTT  Germany
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Quote:
Originally Posted by Flaesh View Post
Slide 21 in Horbach-Keele Presentation Part 2 V4.pdf:
Yes, but they never proved that it worked.

A directional tweeter (waveguide or ribbon) always has larger dimensions than a dome. And this increases the distance of the surrounding drivers (and shifting lobes down in frequency etc.). The whole concept is based on a certain distance between the drivers. A directional tweeter is contrary to the concept.

Last edited by FoLLgoTT; 22nd December 2015 at 07:56 AM.
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Old 22nd December 2015, 08:02 AM   #16
Flaesh is offline Flaesh  Russian Federation
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Originally Posted by FoLLgoTT View Post
And this increases the distance of the surrounding drivers (and shifting lobes down in frequency etc.)..
Yes . (Tried a little but WG was too big)
And thinking about what to do lead to the invention of Synergy horn
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Last edited by Flaesh; 22nd December 2015 at 08:08 AM.
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Old 22nd December 2015, 09:04 AM   #17
ewollowe is offline ewollowe  Australia
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Two with some similarities.


http://www.diyaudio.com/forums/attac...218_110850.jpg

The AK-47 (it's a speaker, not a gun)
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Old 22nd December 2015, 09:30 AM   #18
natehansen66 is offline natehansen66  United States
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Nils - does the pattern hold up at oblique angles?
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Old 22nd December 2015, 10:34 AM   #19
Boden is offline Boden  Netherlands
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Hello Nils,

Superb project! How have you determined the exact placement of woofs and mids? Or should I ask: what software did you use to come the the final design?

Kind regards,
Eelco
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Old 22nd December 2015, 11:34 AM   #20
FoLLgoTT is offline FoLLgoTT  Germany
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Quote:
Originally Posted by natehansen66 View Post
Nils - does the pattern hold up at oblique angles?
Not completely. It gets a bit worse, but not much. I have only simulations yet and have to measure the diagonal direction on the prototype.

Quote:
Originally Posted by Boden View Post
Superb project! How have you determined the exact placement of woofs and mids? Or should I ask: what software did you use to come the the final design?
Thanks! I used ABEC to determine the best positions, sizes and crossover points of the drivers. Usually the prototypes were build after a promising simulation that I designed after an idea. And it always fit good with that.

I'm a bit proud of the optimized alignment of prototype 7. It looks weird and chaotic, but there is a system behind it. I considered the horizontal and vertical directions indepenently.
To shift the side lobes to higher frequencies the drivers must be placed near and equally spaced. You can consider the grid as "weighted". If one driver is on one of the fixed positions the weight is 1. If there are two the weight is 2. All positions must be equal weighted to get the best result.
Prototype 7 is the result to get a high density grid of midrange drivers and to weight all drivers equally in both directions.

Pseudo-coaxial with narrow directivity (and Horbach-Keele filters)-gitter-jpg

With this trick I was able to shift the side lobes to >5 kHz. This is important, because to shape directivity you need both ways to widely overlap in frequency.

Anyway, I skipped the 2-way design and switched to 3-ways. I found that the big horn didn't sound as good as the small one. Sibilants sound much better with the current prototype.
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Last edited by FoLLgoTT; 22nd December 2015 at 11:36 AM.
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