Dymaxion Subwoofer Enclosures to fit your driver specs

Christof · « **on:** 14 Feb 2006, 01:42 am »

DYMAXION SUB...a design for Bucky Fuller.

OK, I'm a self-confessed Fuller junkie. No, I do not live in a Geodesic Dome nor do I drive a space age 3 wheeled automobile but I do think Bucky deserves a wicked subwoofer designed after him. So here it is, my homage, a 26 sided, 120lb, CLD constructed monster of a subwoofer cabinet.

I designed and built a few of these enclosures, about a year ago, for a couple folks here and a few localites. During the construction process I quickly realized why not many of Bucky Fullers ideas ever reached fruition...they are too damn hard to build! Well, these sub cabinets present a serious challenge as well. Finishing a 6 sided enclosure is enough of a chore but add another 20 sides to that same enclosure and you had better find your zen moment in finishing wood. I do. So being a glutton for punishment, I've decided to offer up another handful of these custom enclosures.

With the help of some math gurus over at Purdue I've developed a system to calculate the exact size of all 26 sides for any given internal volume and driver diameter. Because this enclosure has truncated sides I am able to create a given volume of airspace with the least possible amount of surface area for any given side. How does this make for a good subwoofer cabinet? As Bucky Fuller explained as you approach spherical geometery the vessel becomes inherently stronger, ie. geodesic domes. The net result is less vibration meaning less coloration.

You provide the driver dimensions, cut-out specs, internal volume, wood preference, finish preference and I'll do the rest. These enclosures have been used with Shiva drivers, SCC300's, Peerless XLS, Dayton Titanics and Quattro's in anywhere from 1 - 3 cu.ft. vented and sealed. For pricing information send me a PM or email chris(at)terrawooddesign.com

Here are a few pics of various Dymaxion subs

lonewolfny42 · « **Reply #1 on:** 14 Feb 2006, 08:50 am »

Quote

DYMAXION SUB...a design for Bucky Fuller.

An interesting man......[/list:u]

Christof · « **Reply #2 on:** 3 Dec 2007, 11:56 pm »

4 subs = 104 sides = 192 edges to join together

woodsyi · « **Reply #3 on:** 4 Dec 2007, 02:30 am »

Rob, Chris,

If you are going to stack two of them, are you possibly interested in doing a pair of sub tower like Genesis, Nola or even twin one like the Von Schweikert tower of power? I am interested in the VMPS VLAs but I want something with a little slimmer footprint -- similar to what Raw Acoustics offered before. They don't seem to offer any now.

woodsyi · « **Reply #4 on:** 4 Dec 2007, 03:08 am »

I thought you were into insane?

What about stacking the two into one enclosure from the outside, thereby saving some of the edge work (and cost)?

woodsyi · « **Reply #5 on:** 4 Dec 2007, 03:26 am »

Quote from: Marbles on 4 Dec 2007, 03:14 am

From Christof above "As Bucky Fuller explained as you approach spherical geometery the vessel becomes inherently stronger, ie. geodesic domes. The net result is less vibration meaning less coloration."

You would have a rectangle, not a sphere. It could be that it makes sense to have both drivers in a 6 cu foot cabinet, but a 250 LB sub (or more) would be a bit tricky to move around.

I will ask Brian Ding (Rythmik) when I talk to him next.

Yes, that would be nice if you could ask him about twin driver sub in a 6 cu ft encloser. If not, could Chris maintain the internal geodesic design and just veneer the outside into an elongated "bastard" geodesic box?

BTW, Buckminster Fuller was way ahead of his time -- we still haven't caught up with his visions yet.

Christof · « **Reply #6 on:** 4 Dec 2007, 03:28 am »

Because there are many smaller sides vs. the 6 large sides of a traditional enclosure the resonant frequency of the enclosure will be higher. This may or may not have much of an impact since the sub drivers are not likely producing the frequency which excites even a standard 6 sided box.

Christof · « **Reply #7 on:** 12 Dec 2007, 02:53 am »

Beginning of my working shop drawing for Robs array....

Daygloworange · « **Reply #8 on:** 14 Dec 2007, 06:28 pm »

Quote from: Christof on 4 Dec 2007, 03:28 am

Because there are many smaller sides vs. the 6 large sides of a traditional enclosure the resonant frequency of the enclosure will be higher. This may or may not have much of an impact since the sub drivers are not likely producing the frequency which excites even a standard 6 sided box.

Because the size of the large panels has become smaller in the geodesic design, the resonant frequency of those individual panels has gone up considerably as well. They are smaller, stiffer, therefore, less prone to resonate.

Bonus.

These should turn out to be killer subs.

Cheers

klh · « **Reply #9 on:** 14 Dec 2007, 09:05 pm »

Marbles...

If the 15" are 3dB more efficient than the 12" but otherwise have the same specs, then one 15" driver should go just as deep and loud as coupled 12" drivers. Why not save your money on enclosures and just get two 15" drivers instead of four 12" ones?

klh · « **Reply #10 on:** 14 Dec 2007, 09:43 pm »

You could also individually place them throughtout the room if you choose. If you get the chance and have the inclination, could you please try centering one sub on each of the front, rear, left and right walls a la the Harman white paper? This is one of their top choices for reducing the overall in room modal response. It would be interesting to read of your impressions.

MaxCast · « **Reply #11 on:** 14 Dec 2007, 09:54 pm »

Marbles, where and how are you going to xo them with the HT3's?

TomS · « **Reply #12 on:** 14 Dec 2007, 10:23 pm »

Quote from: Marbles on 14 Dec 2007, 10:07 pm

Quote from: klh on 14 Dec 2007, 09:43 pm
You could also individually place them throughtout the room if you choose. If you get the chance and have the inclination, could you please try centering one sub on each of the front, rear, left and right walls a la the Harman white paper? This is one of their top choices for reducing the overall in room modal response. It would be interesting to read of your impressions.

Because of the furniture, built in bar, brick fireplace wall/raised hearth, I'm afraid that would not be possible.

uh, sledgehammer and a dumpster would probably do it, but you'd have to get the adult beverages from upstairs

klh · « **Reply #13 on:** 14 Dec 2007, 11:28 pm »

lonewolfny42 · « **Reply #14 on:** 15 Dec 2007, 08:30 am »

Quote from: Marbles on 14 Dec 2007, 10:38 pm

Quote from: TomS on 14 Dec 2007, 10:23 pm
uh, sledgehammer and a dumpster would probably do it, but you'd have to get the adult beverages from upstairs

The last thing I want is Ellen knowing how much I drink

zybar · « **Reply #15 on:** 15 Dec 2007, 01:39 pm »

Talk about going over the top and pure insanity....I love it!!!

Good luck Rob.

George

Christof · « **Reply #16 on:** 15 Dec 2007, 02:54 pm »

Rob is going to have to sign a waiver......