Spherical subwoofer box

[Mattthecat]

I have been wondering for a couple years now about how a sub would sound in a spherical enclose box? I would like to build one but would like to know a few pointers about it before I buy the materials to build it

 

[shadyJ]

Assuming the enclosure is sturdy enough and properly braced, it shouldn't sound any different than any other decent subwoofer. How do you intend to build the cabinet?

 

[BoredSysAdmin]

reminds of our own resident Gmichael Egg Sub:
http://www.hometheatershack.com/forums/sealed-subwoofer-build-projects/34018-my-egg-shaped-18-sub-build.html

 

[fuzz092888]

http://www.objectreality.co.uk/DeathStarPlans/

 

[highfigh]

If the box isn't terribly large, it could be made of wood and turned on a lathe. For better stability, it could be made using fiberglass, laid over an inflated ball with the ball deflated and removed after it sets. a flange for mounting the driver would be attached and glassed in- as long as it's fastened securely to the shell and assuming the shell is thick enough, it should be resonance-free since a sphere is an inherently rigid form.

FYI- V=4/3Πr³

 

[Mattthecat]

Assuming the enclosure is sturdy enough and properly braced, it shouldn't sound any different than any other decent subwoofer. How do you intend to build the cabinet?

I was wondering about sound quality because I've had square boxes and triangle ones as well as cylinder ones. I've taken more towards a cube but I've been having problems with boxes flexing and the sphere is more structurally sound. Was wondering about since it will reverberate equally on the inside will I get a cleaner hit per say if I was listening to metal. I've had mdf board fall apart on the square boxes. I'm leaning towards fiberglass for materials.

 

[slipperybidness]

Yup,

If the box isn't terribly large, it could be made of wood and turned on a lathe. For better stability, it could be made using fiberglass, laid over an inflated ball with the ball deflated and removed after it sets. a flange for mounting the driver would be attached and glassed in- as long as it's fastened securely to the shell and assuming the shell is thick enough, it should be resonance-free since a sphere is an inherently rigid form.

FYI- V=4/3Πr³

Yup, fiberglass is the defacto method for doing odd shaped custom boxes for cars, typically the smaller sports cars where space is at a premium.

 

[highfigh]

Yup,

Yup, fiberglass is the defacto method for doing odd shaped custom boxes for cars, typically the smaller sports cars where space is at a premium.

Too bad they don't make rectangular balloons- did a small box for an MTX woofer in an Acura NSX using styrofoam and used Acetone to dissolve the form. Nasty odor that filled the shop for hours, even though it was dissolved outside.

 

[slipperybidness]

Too bad they don't make rectangular balloons- did a small box for an MTX woofer in an Acura NSX using styrofoam and used Acetone to dissolve the form. Nasty odor that filled the shop for hours, even though it was dissolved outside.

Haha!

Did you get some jelly goop pouring out when you dissolved the styrofoam? That is very similar to the DIY recipe for Napalm!

 

[highfigh]

Haha!

Did you get some jelly goop pouring out when you dissolved the styrofoam? That is very similar to the DIY recipe for Napalm!

I first heard about using styrofoam as a form when I went to Alpine Electronics car install training- he called the goop "Moose snot".

 

[slipperybidness]

I first heard about using styrofoam as a form when I went to Alpine Electronics car install training- he called the goop "Moose snot".

Yup. "Highly Flammable Moose Snot" would be more accurate!

 

[highfigh]

Yup. "Highly Flammable Moose Snot" would be more accurate!

Until it dries, when it's almost impossible to remove the stuff.

That training session (three days) was in '91 and while learning about sub box design, we were required to use a worksheet and calculator. If most driver data included more than eight parameters, we considered ourselves lucky and some needed to be derived by using formulas that I haven't seen since. Qts is easy enough (product/sum), but the others were right out of the Loudspeaker Design Cookbook.

I don't mind doing the work, but it's so much easier and faster, now.

 

[Speedskater]

While an egg or ball shape can be great for tweeters, the wavelengths at woofer frequencies are so very long it doesn't matter what the box shape is.

 

[darien87]

How about just using a Sonotube? Wouldn't that work?

 

[herbu]

I have been wondering for a couple years now about how a sub would sound in a spherical enclose box?

I've heard they sound real good... http://www.svsound.com/subwoofers/cylinder