Spheres, cones and such..

First of all, excuse my english… I’ll do my best to articulate clearly.

I’m a freshman ID student in Finland, with woodworking background and already I’m thinking about ideas for my degree work.
Apparently I’m constantly wondering (well, it’s more like subconscious meditation) about different concepts for speakers. Having built a pair of boring black boxes of MDF, I want to take things to the next level.

From what I understand, a drop like shape (like the B&W Nautilus pictured below) is, soundwise more or less the optimum for a speaker enclosure. Spheres are also good, as are cones. I spent 4 hours yesterday searching online for manufacturers of hollow balls, and I actually even found some, one of which stated:

Our balls all have roundness, polishing, extreme precision. Now we have our own brand “GoldenBall” and also do OEM for worldwide famous brand. Our balls are accepted all over the world.

That’s just confidence inspiring.

However, I didn’t quite find what I was looking for (yet), so the DIY’er that I am, I naturally started thinking how to make these shapes myself. I’m thinking fiberglass is the way to go, but greener material options would be welcome (yes, a block of wood and a CNC lathe came to mind). Different plastics, or aluminum are also an option, just materials that are easy to work with.

Basically I’m just looking to learn more about the subject and to possibly implement industrial production methods to my own…
Any input and advice on techniques, information resources etc. are welcome.

-Yours truly

You get the idea…

diyaudio.com forum has alot of discussion from people doing same as you, some tips I remember reading:

pair of wooden salad bowls
stainless steel bowls
Ikea bowl hacks
bowling balls

Hi Pier.

I’m a pretty frquent visitor of the diyaudio.com forums. There’s loads of information up there and I tried, really tried, to find some tips on the subject but found nothing relevant.
I’m looking more for information on production methods etc…


It really depends on what you want to make. there are tons of “DIY” level production and prototyping methods anyone can do in their garage. Hand carved elephant ivory…Basic plastic molding with Smooth-On products, epoxying plastic bowls together, carbon fiber with nomex core layup. Figure out what you want to make or pick a process to learn…

your on the right track as far as forming complex shapes, fiber glass, vac forming etc. The thing that you need to remember is a good speaker enclosure is not only stiff but dense. One of the best audio engineers around told me the best speaker cabinets he ever made were out of concrete and weighed 500lbs each.

Roger that ZF, the material properties are as important as enclosure shape. In fact, its probably easier to make a better loudspeaker by focusing on materials, than trying to tune an enclosure, create ports, securely mount bezels, and so on.

The concrete idea is a good one, and could be suited to DIY. I’ve also seen them in Corian and other heavy ceramics. When I was designing speakers, MDF and higher density composites were used in the enclosure and bezel, and then covered in good birch or ash veneer.

The B&W stuff is awesome, awesomely expensive, and probably not very ‘green’ in production methods.

I remember seeing a gourd or pumpkin plant where the gardener had placed a mold around the growing fruit, so the fruit grew into the shape he wanted. Maybe you grow a big pumpkin in a square and hollow it out and see if it would make a good speaker!

A machined mahogany teardrop would be sick too.

For spherical shapes, you could try porcelain. The website for the White Knight porcelain doll (Zeitgeist Toys - Tradition meets Modern Art) shows the closest thing to a round shape from a mould that I could think of. You might even be able to get the basic shape by casting the mould over an existing round object (if you can find a ball of the size you want), and then finish it by hand before firing it up.

A particularly interesting material might be glass. It has a density very close to that of porcelain (Engineering Porcelain :: MakeItFrom.com vs. Soda-Lime (Float) Glass :: MakeItFrom.com). But the main reason I bring it up is because I just saw the most amazing manufacturing video on YouTube: - YouTube (How It’s Made: Marbles). For most people, this belongs in the don’t-try-this-at-home category.

And if you want a cone, consider sheet metal. It’s relatively easy to make by hand: just cut a sheet into an appropriate shape, then bend it around a blank. You can fine-tune mass by stacking cones of thin sheet like disposable cups. And it’s actually highly recyclable – unlike all the ones you pictured, which are destined for the landfill.

Paper mache and a balloon to start with will give you a nice sphere with a very green footprint. Polystyrene spheres would be the second start point. Cover them with concrete soaked burlap for example and dissolve out the styrene gives you a perfect hollow dense shape. Google “polystyrene spheres” and some large sizes are readily available. Some clay pots in recent design news are being used for speakers as well. Plywood circles laminated together to form a hollow sphere, etc.