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Uniform directivity a good OB goal?

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JohninCR

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Re: Uniform directivity a good OB goal?
« Reply #40 on: 27 Feb 2007, 09:32 pm »
Dan,

I think what you want is that shape facing the rear.  This will broaden the dispersion of bass in front by shifting the region of greatest null rearward.  I don't think that doing anything in the front is going to help you out.  A waveguide limits dispersion and you want to broaden it.  You could do something similar to those that I'm working on, but its effect would be limited because the natural dispersion your 15" starts to narrow even before the waveguide's effect would start to kick in.
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DanTheMan

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Re: Uniform directivity a good OB goal?
« Reply #41 on: 28 Feb 2007, 04:39 pm »
Yea, you are correct.  :duh: Thanks so much John for keeping me on the path!

PLease keep us up to date on how your project is going.
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JohninCR

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Re: Uniform directivity a good OB goal?
« Reply #42 on: 1 Mar 2007, 12:01 am »
Quote from: DanTheMan on 28 Feb 2007, 04:39 pm
Yea, you are correct.  :duh: Thanks so much John for keeping me on the path!

PLease keep us up to date on how your project is going.

2" radius roundovers make a BIG difference.  I've seen mid horns and WG's without them, and my opinion now is that those are incomplete.  Styrofoam is proving very easy to work with and shapes to surprizingly smooth form quickly.  I'll be trying quite a few baffle and waveguide ideas in the coming weeks, many of which are untried only because they would have been a pain in the butt using wood.
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DanTheMan

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Re: Uniform directivity a good OB goal?
« Reply #43 on: 5 Mar 2007, 06:54 am »
They should be interesting to see.  Post asap please!
So are you WGs going to be oblate spheroids?  I'm not really clear on how Dr. Geddes is talking about using this shape. A picture is worth a thousand words, and an equation a thousand pictures--only if you can decipher the equation :wink:  If so, how are you going to construct them?
« Last Edit: 5 Mar 2007, 10:44 am by DanTheMan »
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JohninCR

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Re: Uniform directivity a good OB goal?
« Reply #44 on: 5 Mar 2007, 09:38 am »
Quote from: DanTheMan on  5 Mar 2007, 06:54 am
They should be interesting to see.  Post asap please!
So are you WGs going to be oblate spheroids?  If so, how are you going to construct them?

Just conical for now, because they're easy and the formulae seem intuitive.  I'll be more than happy to try an oblate spheriod using a foam based construction.  All I need is dimensions for one using a 4" driver, 90deg dispersion, and say a 900hz lower cutoff. 

I should have front and rear roundovers ready for 2 pairs in the next day or 2, and I'll post pics soon.
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DanTheMan

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Re: Uniform directivity a good OB goal?
« Reply #45 on: 5 Mar 2007, 10:47 am »
have you seen this website?

http://sound.westhost.com/articles/waveguides1.htm#intro

If not, check it out
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