Aperiodic Vents

[MykeysToy]

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.

 

[Inductor]

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

 

[MykeysToy]

Thank you Inductor
That was actually a pretty good read. I think I will have to find some reading material before entertaining any further thoughts though.

Mike

 

[gmilitano]

I have started a short page on Aperiodic Speaker Enclosures. Not too much info yet, but it is growing slowly. Also, here is some more info on the Aperiodic Dynaco Speakers:

http://t-linespeakers.org/classics/dynaco.html

 

[Inductor]

Thanks to you gmilitano, it's my pleasure to go and read it about it. Maybe this thread can be a souce of information on this same theme.

 

[planet10]

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

 

[MykeysToy]

Ooohhhh! That was nice!

 

[kelticwizard]

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:

 

[kelticwizard]

And here is the enlargement of the back, showing the "distributed vent", or small vent holes. It looks like eight holes across, 11 rows from top to bottom.

 

[MykeysToy]

This was focused on car audio but seems to explain a bit. I just have to wonder how much is psudo-science and how much is actually fact.


http://www.audiogearreviews.com/tech/theory/enclosure_design/aperiodic_membrane.asp

 

[planet10]

I am not sure what purpose the dividers in the middle of the enclosure serve.

Primamry purpose is bracing. Secondary is to define the tunnel. Third is support for the damping.

It is intesting to note that these speakers were made from a in-house 7 layer plywood made of HDF.

dave