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Old 3rd October 2007, 03:34 PM   #1
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Default Directional Subwoofer

Hello everybody,
I read in brochure of M3DS from MEYER sound this subwoofer have a directivity, but they dont tell the exact way.
Has any one try to made or experiment to made a DIY directional subwoofer ? dont mind to share the recipe ?
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Old 3rd October 2007, 04:03 PM   #2
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Is the M3DS an array? Meyer is known for their phased arrays, which are steerable, but it seems to me that steering sound at very low frequencies would be problematic.
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Old 3rd October 2007, 05:05 PM   #3
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It's cardioid sub, I guess it is obtained by using front/rear woofers and properly delaying the rear woofer such that to obtain a cardioid pattern.

It can also be done DIY. An example is NaO which uses a U-Frame:

http://www.musicanddesign.com/NaO-II-U-frame.html

There was also a 2-woofer version somewhere, but I couldn't find it anymoore.
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Old 3rd October 2007, 05:22 PM   #4
dangus is offline dangus  Canada
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Maybe it was at Meyer sound, but I read someplace that you can get similar directionality to microphone patterns like cardioid or figure-8. It requires multiple subs, spaced apart and with time delays so that there's gain in one direction and cancellation in the other. It might be practical for a large suburban property where money isn't an obstacle, or outdoor concerts.
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Old 3rd October 2007, 05:22 PM   #5
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Default Re: Directional Subwoofer

Quote:
Originally posted by Rembulan
Hello everybody,
I read in brochure of M3DS from MEYER sound this subwoofer have a directivity, but they dont tell the exact way.
Has any one try to made or experiment to made a DIY directional subwoofer ? dont mind to share the recipe ?
If you put several subs on a line, let say that you use them between 40-80Hz then make them 1/2 the wavelength of 60Hz apart and put them out of polarity with eachother.
Arranged like that they will add together on the line where the difference in distance equals a half wavelength and cancel eachother on the sides where there arent any delay between them.

The meyers work in a similar way as that. They have 18incers on the front and 15inchers on the back that are out of phase with eachother in a way that makes them add constructively infront of the box and destructively behind the box, Thereby making the bass directional.

http://www.meyersound.com/products/mseries/m3d-sub/
"A pair of 18-inch drivers is mounted at the front of the cabinet, and works in conjunction with a pair of 15-inch drivers facing the rear and is driven by a sophisticated phase manipulation circuit."
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Old 3rd October 2007, 07:56 PM   #6
MaVo is offline MaVo  Germany
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perhaps one could put a closed box sub and a dipole sub, both using the same driver, equalised to the same response, on top of each other (perhaps with the monopole firing to the rear and having reversed polarity). the back wave of the dipole is out of phase with the monopole, so they should cancel, which would leave only the front lobe of the dipole figure of eight.

is that possible?
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Old 4th October 2007, 09:43 AM   #7
Rudolf is offline Rudolf  Germany
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Quote:
Originally posted by MaVo
perhaps one could put a closed box sub and a dipole sub, both using the same driver, equalised to the same response, on top of each other (perhaps with the monopole firing to the rear and having reversed polarity). the back wave of the dipole is out of phase with the monopole, so they should cancel, which would leave only the front lobe of the dipole figure of eight.
is that possible?
You will find a description of your proposed system here and a lot of other related information in german in this place .
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Old 4th October 2007, 03:04 PM   #8
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They have 18incers on the front and 15inchers on the back that are out of phase with eachother in a way that makes them add constructively infront of the box and destructively behind the box, Thereby making the bass directional.

Thanx for made it better to understand.

I will try it soon
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Old 4th October 2007, 04:38 PM   #9
MaVo is offline MaVo  Germany
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Quote:
Originally posted by Rudolf


You will find a description of your proposed system here and a lot of other related information in german in this place .

Thanks for the information. Very interesting!
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