Please critique this design....

[Christof]

I've posted a few other times asking for design help on this project and recieved very helpful feedback. Now I'm asking for a "ROAST" please give me any pros or cons, likes or dislikes to this 26 sided enclosure shape (rhombicuboctahedron) when used for a sub.

Rule out any complications in construction, I created a Excel program that will determine the exact exterior dimensions for all sides of this shape given any internal volume I plug in. And I own a cabinet shop to build them in.

So far I've built blank .75"MDF enclosures in the following sizes: 1.3cu.ft (10" baffles) , 1.62 cu.ft (10.5" baffles), 2.8cu.ft (11.5" baffles) and 3.2ft (13" baffles)

This enclosure will comfortably hold between 2 and 6 drivers.

Please fire away at this design...I asked for it!
thx...Chris

http://ncd296.spencer.netclusive.de/...trilo_urps.jpg

[CeramicMan]

Why such a complicated shape? In many cases people mention diffraction and reducing standing waves inside the enclosure - without realising that the wavelength is likely to be in the range of 3 to 17 metres and the shape of the box won't make much difference. If each woofer requires a box volume of say 20L, well then the combined volume should be 120L, unless appearances are deceptive and that box is bigger than it looks. I assume the huge black boxes that look like amplifiers will power this beast to keep you warm in winter ?

I'm assuming your sub is designed for "SPL" - high volume, lot's of stress on each woofer, and if one of them were to stop working, then that wouldn't be particularly good for other 5 woofers either....Unless you made 6 separate enclosures in anticipation of failure. Ok I tried being harsh, but that's the best I could do.

CM

[Stephen D]

While it's aesthetically interesting looking it's complexity serves absolutely no practical or functional benefit that I can determine. In fact the shape poses somewhat of a drawback in that the fairly large amount of living space it consumes is compounded by the fact that nothing can be set on top of it in any way to allow it to at least serve some double utilitarian duty... not even a book... but then I guess it's meant to stand out alone as it's own loud artistic decor statement. I assume you intend to include a grill to protect the woofers (especially the upward firing from falling objects.)

It gets a major thumbs down from me for practicality & functionality but I suppose the average person with no knowledge of acoustics & speaker design might find it a pleasing piece of decor.

[sreten]

While it's aesthetically interesting looking it's complexity serves absolutely no practical or functional benefit that I can determine.

Erm.... not quite true, the shape is inherently
more rigid than an equivalent plain box.

In fact the shape poses somewhat of a drawback in that the fairly large amount of living space it consumes

This is only due to the choice of the base mounting, a
standard box cube could be set onto a base this way.

Personally think it would look quite nice with a
single driver face down and 4 feet on that face.

I'm assuming your sub is designed for "SPL" - high volume, lot's of stress on each woofer, and if one of them were to stop working, then that wouldn't be particularly good for other 5 woofers either....

The well known Linkwitz Transform would need to be used,
isolating each driver is also a choice needed for plain boxes.

Personally I can't see any wrong with the box design
at all, as long as getting the pieces cut is not a hassle.
In a normal orientation it will look small for its size.

Has some similarities with Tannoy's six
sided truncated triangular speakers.

sreten.

[Bill Fitzpatrick]

I think it looks great! I'll bet is sounds good too.

[Peter Menting]

As a fellow woodworker I applaud your project, it certainly must have taken a great deal of effort to create and the end result is most impressive. Since it is such a unique design I can only ask "How does it sound?"--- I believe that is the only criteria that matters!

Nice work!
Pete

[masterp2]

Chris,

You are good, no doubt about that.

could you post the excel file here as an attachment. I'd love to see your work. That is not easy, you must have been a math major.

[Christof]

Thank you all for the replies. My response to a couple things mentioned.

The foot print that this enclosure takes up is surprising. if set on one of the larger sides like a typical sub enclosure would sit the dimensions of the pictured box is 18" x 18" x 18" Whent the cube si truncated in this fashion and set on one of the small corners (like the one in the pic) its footprint turns into 19.5 x 19.5 x 19.5. So it really does not consume much more space than a box.


Admittedly this enclosure was built based on aesthetic. While it may not fit the design aesthic of most homes I wanted something that would work in my home (modernist architecture).

This enclosure allows for great flexibility. You could, if crazy enough place drivers on all 6 sides.

I will gladly provide the exterior dimensions for people if they provide me with a target interior volume.

Can you guys recommend any driver arrangements. I have a bunch of these enclosures to experiment on.

thanks for all the great ideas & help
cg

[netgeek]

Originally posted by Stephen D
While it's aesthetically interesting looking it's complexity serves absolutely no practical or functional benefit that I can determine. ..

It gets a major thumbs down from me for practicality & functionality ...

The exact same statement could be applied to any number of objects found in a typical art museum !!!
And I think this creation pretty much qualifies as art. To make it practical - How about a single Peerless XLS with the matching passive radiator? That would be just about perfect in ~2 sq. ft. version - and it would preserve the aesthetics as well...

I give it two thumbs up - no, make that THREE thumbs up (as in a Picasso I once saw where the guy actually HAD three thumbs)... But that was art too!

[kingdaddy]

I’m a big fan of unconventional and unique enclosure designs, so I love the looks and the design. However since you asked for critiquing I will have to mention the one drawback I see, Price, 4 to 6 woofers and the power required to move them to reference levels would be IMO too much considering you can do the same thing with a single woofer and 2 passives in the same size and shape box.

I really like the way the box looks and the stand shows it off nicely, but the cost must be astronomical.