I see in the past there has been interest in non-rectangular enclosures, with the benefits they offer
http://www.diyaudio.com/forums/showthread.php?threadid=117251&highlight=
How do I make spherical enclosures?
The 1st DIY efforts I saw ( circa SB mag in the 80's ) were fabricated from slices of wood laminated together to form the rough shape. This was sanded down to final shape.
I did not want to follow this approach, and I wanted to use something other than wood, usually a process of removal from a rough form.
I wanted to be able to create any shape desired, so I would cast from a shape. Others have used hard shapes like glass balls ( ie lawn balls gazing balls etc ), and cast 2 hemispheres which they fused together.
Others use a sacrificial mold, like an plastic ball that can be deflated or popped. Others build a shape from modeling clay.
Fiberglass fabric and polyester resin are predominately used for the shell.
For use as the smallest spherical satellites possible, I borrowed a few techniques/materials from the stage craft world, to create (2) 8" spheres for approx $35.
Very Briefly:
I used a spreadsheet to run volume iterations for various geometric shapes including spheres and determined that minus speaker and port volume that an 8" sphere would be what I needed for some Vifa 4 1/2 drivers ( outsourced for Revel ).
I found an 8" Styrofoam ball at the crafts stores, I cast the initial shape using Tarlatan reinforced with Gloss Medium ( latex ).
That was removed and attached to a plywood ring baffle cut for the drivers.
This shape was layered and built up with plaster bandages ( used to set broken bones ) several layers thick.
On top of that was placed polyester auto body filler and sanded to shape.
Auto Body centers also have a thinner finishing putty for final finish.
The shell of the sphere being comprised of differing layers results in a strong yet inert enclosure. I tuned these to 80Hz f3.
This is almost all hand work with a lot of sanding. The quality and techniques of finish ( including marbling techniques, and auto finish materials ) depends greatly on the skills of the builder.
I invite others to share their work and ideas.
http://www.diyaudio.com/forums/showthread.php?threadid=117251&highlight=
How do I make spherical enclosures?
The 1st DIY efforts I saw ( circa SB mag in the 80's ) were fabricated from slices of wood laminated together to form the rough shape. This was sanded down to final shape.
I did not want to follow this approach, and I wanted to use something other than wood, usually a process of removal from a rough form.
I wanted to be able to create any shape desired, so I would cast from a shape. Others have used hard shapes like glass balls ( ie lawn balls gazing balls etc ), and cast 2 hemispheres which they fused together.
Others use a sacrificial mold, like an plastic ball that can be deflated or popped. Others build a shape from modeling clay.
Fiberglass fabric and polyester resin are predominately used for the shell.
For use as the smallest spherical satellites possible, I borrowed a few techniques/materials from the stage craft world, to create (2) 8" spheres for approx $35.
Very Briefly:
I used a spreadsheet to run volume iterations for various geometric shapes including spheres and determined that minus speaker and port volume that an 8" sphere would be what I needed for some Vifa 4 1/2 drivers ( outsourced for Revel ).
I found an 8" Styrofoam ball at the crafts stores, I cast the initial shape using Tarlatan reinforced with Gloss Medium ( latex ).
That was removed and attached to a plywood ring baffle cut for the drivers.
This shape was layered and built up with plaster bandages ( used to set broken bones ) several layers thick.
On top of that was placed polyester auto body filler and sanded to shape.
Auto Body centers also have a thinner finishing putty for final finish.
The shell of the sphere being comprised of differing layers results in a strong yet inert enclosure. I tuned these to 80Hz f3.
This is almost all hand work with a lot of sanding. The quality and techniques of finish ( including marbling techniques, and auto finish materials ) depends greatly on the skills of the builder.
I invite others to share their work and ideas.
Ted:
I have been looking through my Hard Drive archives to retrieve and organize the various bits and pieces of spherical & Ovoids speakers:
Until then - this link:
http://modsandends.com/?m=200810
Shows an effort that ends up with result very similar to what I did.
My method and approach was different:
I have been looking through my Hard Drive archives to retrieve and organize the various bits and pieces of spherical & Ovoids speakers:
Until then - this link:
http://modsandends.com/?m=200810
Shows an effort that ends up with result very similar to what I did.
My method and approach was different:
Many thanks for the link to get me here, it makes very interesting reading.
My only comment is, wouldn't it have been a little easier, saving on lots of sanding, to make a female mould from half the ball first. Then make the required number of halves, joining them later. This would allow to work laying-up the mould from the inside.
The finished surface of the sphere would then be just as smooth as the original ball. You'll also have a mould that you could use for later productions.
Anyway, very good work, but you didn't say how they sounded which is a very important consideration.
Paul
My only comment is, wouldn't it have been a little easier, saving on lots of sanding, to make a female mould from half the ball first. Then make the required number of halves, joining them later. This would allow to work laying-up the mould from the inside.
The finished surface of the sphere would then be just as smooth as the original ball. You'll also have a mould that you could use for later productions.
Anyway, very good work, but you didn't say how they sounded which is a very important consideration.
Paul
The easiest way is to head down to your nearest IKEA (or their online store in whatever country you live in), and pick up a couple of their salad bowl.
For example this one in wood:
http://www.ikea.com/us/en/catalog/products/40057259
But there's another cheap and very good way to make a good mold. Take a plastic football (soccerball) or any sort similarly sized ball, and a tennis ball or another similarly sized ball. Now make a cardboard cone that fit the diameter of each ball on either end. Glue it up. And you have the perfect mold for a spheroid speaker.
For example this one in wood:
http://www.ikea.com/us/en/catalog/products/40057259
But there's another cheap and very good way to make a good mold. Take a plastic football (soccerball) or any sort similarly sized ball, and a tennis ball or another similarly sized ball. Now make a cardboard cone that fit the diameter of each ball on either end. Glue it up. And you have the perfect mold for a spheroid speaker.
EDIT: My sphere is 6" diameter not 8"
Here is my proto: ( from several years ago )
Google Images for:
speaker "sphere"
And another approach:
http://flickr.com/photos/jonathanwightman/2353542862/
More to follow:
Here is my proto: ( from several years ago )
An externally hosted image should be here but it was not working when we last tested it.
Google Images for:
speaker "sphere"
And another approach:
http://flickr.com/photos/jonathanwightman/2353542862/
More to follow:
Yes I delayed answering...
I built these in 2003 and have yet to find the specs/notes/etc...
I built these for several reasons:
(1) The audible effects of diffraction has fascinated me since I bought a pair of Focal Eggs in the 80's.
(2) I wanted to explore the possibilities of a small satellite, for back channel speaker (AV) setup
(3) A mini near-field monitor system for computer editing I was doing on a video.
(4) A mini system for kitchen/background/outdoor.
(5) Try out fabricating non-rectilinear cabs using new and non traditional materials and techniques.
When I built mine, I did not have the means to measure T/S so I did it by the numbers and used the PE published specs on this Vifa. I picked the sphere volume and tuned to 80Hz ( it's Bass Reflex ).
More recently WTII measures @ 77Hz
It is used above 80Hz, <80Hz goes to a small sub woofer.
You can't get real bass with a 4" speaker.
It sounds much better with an active crossover, to save it from working on the bottom octaves.
It doesn't have the extended high range ( a better 4 or a coax would probably cure that ). A small boost with the treble corrects for the most part.
It sounds much better than the usual drek sold as mini A/V and PC sound packages. ( but that's not to hard to do anyway ).
It works very well near field. and as a portable outside system
All in all it was well worth the effort and sounds much better than than the same 4" driver in a box.
Obviously my method while very cheap in materials, is labor intensive.
But this was a proof of concept and many of the shapes to cast a mold from were not readily available ( to me anyway ) at that time.
It's certainly easy and cheap enough for virtually any DIYer to build and hear for themselves.
Eggs past and future
from http://www.tokyomango.com/tokyo_mango/2007/07/smooth-egg-shap.html
An externally hosted image should be here but it was not working when we last tested it.
from http://www.tokyomango.com/tokyo_mango/2007/07/smooth-egg-shap.html
Hello:
I am sorry of not helping to inform about a suitable material, but I would like to contribute with a spreadsheet I prepared to define the dimensíons of an egg shape shell, for a two way system.
If you are interested, you only need to enter the external dimensions of the shell, the wall thickness and the outer diameters of the units (woofer and tweeter). These entries are marked with blue numbers into the cells.
The shell is build up by joining a hemisphere with an ellipsoid, just by the middle.
Any contribution to improve the spreadsheet is welcome.
Kind regards,
Hugo
I am sorry of not helping to inform about a suitable material, but I would like to contribute with a spreadsheet I prepared to define the dimensíons of an egg shape shell, for a two way system.
If you are interested, you only need to enter the external dimensions of the shell, the wall thickness and the outer diameters of the units (woofer and tweeter). These entries are marked with blue numbers into the cells.
The shell is build up by joining a hemisphere with an ellipsoid, just by the middle.
Any contribution to improve the spreadsheet is welcome.
Kind regards,
Hugo
Hello:
I am sorry of not helping to inform about a suitable material, but I would like to contribute with a spreadsheet I prepared to define the dimensíons of an egg shape shell, for a two way system.
If you are interested, you only need to enter the external dimensions of the shell, the wall thickness and the outer diameters of the units (woofer and tweeter). These entries are marked with blue numbers into the cells.
The shell is build up by joining a hemisphere with an ellipsoid, just by the middle.
Any contribution to improve the spreadsheet is welcome.
Kind regards,
Hugo
I am sorry of not helping to inform about a suitable material, but I would like to contribute with a spreadsheet I prepared to define the dimensíons of an egg shape shell, for a two way system.
If you are interested, you only need to enter the external dimensions of the shell, the wall thickness and the outer diameters of the units (woofer and tweeter). These entries are marked with blue numbers into the cells.
The shell is build up by joining a hemisphere with an ellipsoid, just by the middle.
Any contribution to improve the spreadsheet is welcome.
Kind regards,
Hugo
Nice spreadsheet Hugo:
These pics:
Shows the axial relationships:
As per your spreadsheet it rotates around the Y axis.
So a rough form can be chucked and rotated ( lathe style ) and smoothed down Or,
Built up using the ovoid negative as a pattern tool.
As summarized earlier:
At the time I could not find a suitable surface to lift a negative cast ( unlike today ).
So a crafts store Styrofoam ball of desired diameter ( up to 12" ) was a cheap alternative.
Instead of laying up fiberglass cloth, and polyester resin;
I layered w Tarlatan fabric painted with Gloss Medium ( latex ).
After 3 layers dry, I remove this positive shell.
The 2nd layer of plaster bandages are applied over this 1st layer:
At this point the shape can further shaped and modified:
I extended out the front of my sphere to meet the 4.25 plate I used to mount a Vifa KG10-MD-06-09.
3 layers of plaster bandage is sufficient.
Then I used the auto body filler with ( fibers ) for the course outer layer and the creamier finishing putty for the final surface.
Worked and finished like a auto body.
The final thickness is less than .5" and very strong. It was accidentally dropped and suffered no damage. The layers also made it acoustically inert ( no ring ).
These materials are not high tech readily available and very cheap.
This is a free form method suitable for unique and limited production: Much like a breadboard vs a PC board.
The method I used would allow me to make or cast from virtually any shape imaginable ( even if it has no acoustic merits ).
These pics:
An externally hosted image should be here but it was not working when we last tested it.
Shows the axial relationships:
As per your spreadsheet it rotates around the Y axis.
So a rough form can be chucked and rotated ( lathe style ) and smoothed down Or,
Built up using the ovoid negative as a pattern tool.
As summarized earlier:
At the time I could not find a suitable surface to lift a negative cast ( unlike today ).
So a crafts store Styrofoam ball of desired diameter ( up to 12" ) was a cheap alternative.
Instead of laying up fiberglass cloth, and polyester resin;
I layered w Tarlatan fabric painted with Gloss Medium ( latex ).
After 3 layers dry, I remove this positive shell.
The 2nd layer of plaster bandages are applied over this 1st layer:
At this point the shape can further shaped and modified:
I extended out the front of my sphere to meet the 4.25 plate I used to mount a Vifa KG10-MD-06-09.
3 layers of plaster bandage is sufficient.
Then I used the auto body filler with ( fibers ) for the course outer layer and the creamier finishing putty for the final surface.
Worked and finished like a auto body.
The final thickness is less than .5" and very strong. It was accidentally dropped and suffered no damage. The layers also made it acoustically inert ( no ring ).
These materials are not high tech readily available and very cheap.
This is a free form method suitable for unique and limited production: Much like a breadboard vs a PC board.
The method I used would allow me to make or cast from virtually any shape imaginable ( even if it has no acoustic merits ).
Here are screen shots of a concept I have been noodling with for the last few weeks.
Not ready to commit to construction yet. Still changing proportions, and shapes to get a cohesive look.
This will house a Seas coaxial unit. Not sure that I will like the end result since I've never heard the driver, but I am fascinated with the idea of all frequencies coming from the same point in space.
My original idea was a simple ellipsoid. On a whim I sent an email to Lynn Olson in hopes that he would comment. He's a very nice guy, and offered several suggestions. The most important was that I investigate the B&W Nautilus, as he felt that was the most favorable shape.
What you see here is the result of his recommendations.
Construction will be by CNC milling machine. The top and bottom will be machined from MDF, and the post will be aluminum.
The wires will run throught the post, and the bottom of the base will be pocketed to house the crossover.
Spikes will be incorporated into the base which will hopefully make it harder for my dogs to tip them over.
I may also pocket the base and build in some aluminum structure to attach the spikes.
The base is 3" thick, but I suspect it may have a tendency to creep over time if it is loaded at just 4 points.
Since I really don't know WTF I am doing, does anyone have a comment/suggestion?
PY
Not ready to commit to construction yet. Still changing proportions, and shapes to get a cohesive look.
This will house a Seas coaxial unit. Not sure that I will like the end result since I've never heard the driver, but I am fascinated with the idea of all frequencies coming from the same point in space.
My original idea was a simple ellipsoid. On a whim I sent an email to Lynn Olson in hopes that he would comment. He's a very nice guy, and offered several suggestions. The most important was that I investigate the B&W Nautilus, as he felt that was the most favorable shape.
What you see here is the result of his recommendations.
Construction will be by CNC milling machine. The top and bottom will be machined from MDF, and the post will be aluminum.
The wires will run throught the post, and the bottom of the base will be pocketed to house the crossover.
Spikes will be incorporated into the base which will hopefully make it harder for my dogs to tip them over.
I may also pocket the base and build in some aluminum structure to attach the spikes.
The base is 3" thick, but I suspect it may have a tendency to creep over time if it is loaded at just 4 points.
Since I really don't know WTF I am doing, does anyone have a comment/suggestion?
PY
Pics for Seas Coax Cabinet
An externally hosted image should be here but it was not working when we last tested it.
injectordynamic
Any particular Seas driver model number?
I have yet to see that shape elsewhere to use to pattern off ( a mold ).
There is discussion as to merits of any exotic curving shape beyond spherical or ovoid.
The KEF 207/2 uses a slightly ovoid(?) enclosure for the 6.5" Mid/HF driver, the B&W 802 however looks slightly more elongated on it's Kevlar driver and much more so on the tweeter portion.
Any particular Seas driver model number?
I have yet to see that shape elsewhere to use to pattern off ( a mold ).
There is discussion as to merits of any exotic curving shape beyond spherical or ovoid.
The KEF 207/2 uses a slightly ovoid(?) enclosure for the 6.5" Mid/HF driver, the B&W 802 however looks slightly more elongated on it's Kevlar driver and much more so on the tweeter portion.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.