Aperiodic Vents

MykeysToy said:
Such as this one
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=296-546

When and how should they be used? How does it figure in when designing and enclosure ETC. I would like to know for the hell of it but it may be useful in my reg cab P/U just kicking around an idea.

I am not sure, and I can't remember a software available to simulate it. In essence is a "large" (infinite) (en)closed box with a damped vent, resulting in a less peak at the system resonance.

Read here about Dynaco Speakers:

http://home.indy.net/~gregdunn/dynaco/components/speakers/index.html
 
One of the most advanced aperiodic boxes built was the PEARL PR-2. A huge amount of real R & D went into this. It was in mainy respects a model i have based some of my designs on...

I've attached a picture.

Bill's series of holes with high density open cel foam as additional resistance works very well, but is quite labour intensive if you plan on veneering it. I have found the long skinny slot like the Dynaco one of the easiest to implement. The resistance unit for this can be made with 2 pieces of mesh (ie plastic gutter mesh) and 2-4" of fiberglass insulation.

dave
 

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kelticwizard

diyAudio Moderator Emeritus
2001-09-18 2:33 am
Connecticut, The Nutmeg State
That is a very interesting enclosure. The small holes in the back were called a "distributed vent" by Neville Thiele, (of Thiele-Small fame).

I enlarged the pic of both the drawing, so that you can see the captions of what is written on the inside, and also of the back view photo of the finished enclosure.

The interior seems to be filled with densely packed stuffing. Behind the woofer is a small open space, then a tunnel leading through the densely packed stuffing from that space directly to the vent holes. The tunnel is made of lighter packed stuffing.

I am not sure what purpose the dividers in the middle of the enclosure serve. It might make the enclosure a three chamber aperiodic enclosure, something I have not seen before, or it might just serve to hold the stuffing up. Not certain.

Anyway, here is the enlarged drawing so you can read the printing about the stuffing densities:
 

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