driver for CB2 sphere?

[h-bar]

Hi all,
I picked up a couple of 6" diameter stainless steel spheres from CB2 and would like to install some widerange drivers in them. I'm asking for driver suggestions. The spheres' internal volume before modification is 1.8 L; if I damp the walls internally it'll obviously be a bit less than that.

I'm looking for a driver that can operate without a tweeter, but I expect to add a small woofer in a separate enclosure. I don't have a fixed crossover frequency in mind, but I'd like it to be below 400 Hz. Also, the design is not going to be used in a system that has to reach high SPLs. I'll either use it around my computer system or perhaps elsewhere in an office or other small room.

Tang Bands are one option I've considered but I'm not on top of what users have been experiencing with TB's current offerings. One other constraint I should note is that it seems something with a round face plate would be easier to mount than would other shapes.

If anyone out there is more up to date on current offerings than I am, I'd appreciate some suggestions. If nothing else, I thought I'd bring these spheres to the attention of other speaker diy-ers. They feel pretty sturdy---much more suitable for enclosures than the aluminum spheres CB2 also sells.

In case anyone is wondering, I haven't yet worked out a great way to put a nicely formed hole in them. I am open to suggestions, though.

Thanks in advance,
h-bar

[HareBrained]

The simple answer would be the HiVi B3N. It's been used in several single driver speakers but the volume may be too small or the shield may be too big.

Next suggestion would be the TB W2-803SM. The frame is square but the small size would fit the sphere well.

Lastly, the W3-881SJ may be the best option. It's shallow mounting with a paper cone (none of the metal cone break-up) make it an easy fit.

I don't think you're going to be able to fit the TB W4-1337SA, but it's easily the best single driver (with a reasonable price).

All are going to reach below 400Hz.

BTW, you'll be lucky to have half of the volume (~.9L) when you're done. You're going to have to slice away about a third to create a large enough opening and then a good amount of the volume will be taken up by the driver.

[h-bar]

Thanks for the driver suggestions; I'll take a look. I had thought about the volume lost to the driver's magnet etc. and so was hoping to find something with a NdFeB magnet system to minimize the problem. I don't think I gave sufficient consideration to the loss of volume resulting from slicing off a good chunk of the sphere, though. That'll clearly be necessary in order to mount the driver, so thanks for pointing that out.

h-bar

[mike93lx]

you could always use a small piece of stainless steel tube to mount the driver to and then to the sphere. it would recover the lost volume and make mounting easier.

you can get up to 6" OD Stainless tube from this site (as well as many, many other metals) in any size that you need.

[mike93lx]

h-bar, when you do end up drilling or cutting the sphere, could you let us know how thick the walls are? thanks!

[h-bar]

you can get up to 6" OD Stainless tube from this site (as well as many, many other metals) in any size that you need.

Which site were you suggesting?

I'll certainly be happy to report on wall thickness when I have some information. These spheres are kind of a secondary project for me. I'm working on some tensioned wire electrostatic panels with dipole woofer arrays at the moment. That project has become the ultimate "three steps forward, two steps back" experience. I was sort of hoping the spheres would provide some more instant gratification, but I'm sure they'll be the source of unexpected fun as well.

h-bar

[mike93lx]

sorry, i forgot the link.

http://www.onlinemetals.com/merchant.cfm?id=19&step=2&top_cat=1

[alias2]

Search Diyaudio.com for spheres, there are a quite few threads.
~ 2 Litres is right for a 3", and a 3" can get away with no tweeter.