Cabinet materials - why not more diversity?

[Andy G]

is called 'Hebel" blocks.. It would probably have to be built "in situ" , but maybe the Hebel panels might be usable. Hebel is a liteweight aerated cement product, in blocks or panels.

http://www.hebelaustralia.com.au/default.asp

[Andy G]

... is only relative to the weight of ordinary cement !!

and I would envisage using this stuff about 2" thick at least !!

[Nat Eddy]

Advent used to have a couple of speakers that had expanded foam cabinets and perforated aluminum grills. The outer layer of the foam was much denser and harder than the internal layer, and the boxes were not much lighter than wood, though I think they were cheaper to manufacture. I owned a pair of them (an Advent II maybe?) and thought they sounded sweeter and less boxy than standard Advents, but they were also dramatically less easy to integrate into the average decorating scheme, since they were white with silver grills. This was ok in the 70s, maybe, but probably less popular later.
The later Bozaks -- made in Taftville, not Norwalk, and using conventional drivers -- had regular appearing cabinets but the actual enclosure was half of a sonotube (the cardboard tubes used as forms for poured concrete columns) built into the box with the gaps filled with poystyrene foam. I have a pair of these, but can't comment on the sound because a part of the midrange contouring circuit was fried, leading to a dead short in both midranges.
I can't find any information about component values and so I suppose I have to unwind the coils, and reproduce them. What a pain. Anyone know what happened to the people who worked there -- I think the designer was named David Luchs -- I sure would like to find out the values of the coils.

[7V]

Originally posted by Nat Eddy
Advent used to have a couple of speakers that had expanded foam cabinets and perforated aluminum grills. The outer layer of the foam was much denser and harder than the internal layer

I'm a strong advocate for soft on the inside, hard on the outside for mid-range enclosures and chocolates. Hard and rigid is perfect for bass but, usually, too reflective for mid-range. It also breaks your teeth.

Steve

[EC8010]

Originally posted by 7V
I'm a strong advocate for soft on the inside, hard on the outside for mid-range enclosures and chocolates. Hard and rigid is perfect for bass but, usually, too reflective for mid-range. It also breaks your teeth.

The phrase you're looking for is "constrained layer damping." I'm afraid I don't like constrained layer chocolates, preferring the Corian variety (dark chocolate with mint chips).

[7V]

Originally posted by EC8010
The phrase you're looking for is "constrained layer damping"

Yes, that's the stuff. What flavours does it come in?

Steve

[EC8010]

A company called Wilhams Insulations in Hastings used to make an MDF/bitumen/MDF sandwich which was used by JBL. Another company called Rowntree makes a dark chocolate/minty goo/dark chocolate wafer, but its temperature stability is poor and it's only available in quite small tiles.

[Da5id4Vz]

WS Slater makes a very tasty sucrose composite. It likely doesn’t have any purpose related to speaker building, but they will extrude batches with customized lettering embedded in the core.

http://www.slaters-rock.co.uk/

[7V]

Originally posted by Da5id4Vz
WS Slater makes a very tasty sucrose composite. It likely doesn’t have any purpose related to speaker building

Still, don't write it off before you've tasted it.

[Ian J]

...here's my silly contribution. Has anyone ever investigated porous cabinets - would they be akin to some form of 'asynchronous' loading (ie like a sealed box with a hole)?
IJ