Balsa Cabinets?

[dnsey]

Thanks everyone for your replies.
Yes, Filgor, I was really thinking of using just Balsa, probably cross-laminated for stability and to avoid having to source large panels.
I suspect that it would indeed work well as a composite (I've used expanded polystyrene, which has some similar properties, that way), but I was interested in the surface properties, which hopefully would obviate the need for damping.
(Train of thought: making experimental horn from balsa for convenience - wondered if it needed a 'hard' finish applying to avoid absorption of HF - realised that this was desirable for cabinets - considered possibility of trying it.)
I appreciate the comments regarding weight - I think I'd probably arrange for a sandbag in the base to keep things steady, but I'm not sure to what extent mass is necessary for effective damping.
I'm sure that large slabs of balsa are pricey, but the sammer bits, which would be OK for laminating, seem fairly reasonable. OTOH, I wonder if there are still any scrapyards with old mosquitos...
A lot more projects to complete before trying much in this line, but I might have a go at a little cab for a 3" driver just to see how it turns out - unless one of you gets there first, of course

[EC8010]

If you go for a composite you will get your damping from the core - it's known as constrained layer damping, and it's very effective.

[filgor]

Originally posted by owen
The celestion aerolam speakers are fairly lightweight, and I see no reason why the balsa composite should not be as stiff.
Owen

Absolutely.

No argument against this at all. I think a well designed, well braced and skinned balsa cabinet is a fantastic DIY alternative to aluminium honeycomb cabinets. I also think that closely spaced bracing of cabinet walls across to opossing walls (and bracing between bracings) will result in a very stiff cabinet. This would be particularly simple and practical to achieve with balsa.

I'm mainly concerned with the significance of the ratio of cabinet mass to the drivers net moving mass... Any ideas as to when, if at all this would become an issue?

[EC8010]

If this was done as an experiment, perhaps using the Fostex FE103, then the mass of the cone compared to the magnet is tiny anyway, and a heavy box always assumes that the basket supporting the magnet is perfectly rigid. Since a popular FE103 modification is to wedge caulking compound between the magnet and the basket, I think we can assume it isn't perfectly rigid. I don't see a problem with a light box.

The SL600 undoubtedly had a heavier cone in comparison to the box...

[filgor]

Originally posted by EC8010
If this was done as an experiment, perhaps using the Fostex FE103, then the mass of the cone compared to the magnet is tiny anyway, and a heavy box always assumes that the basket supporting the magnet is perfectly rigid. Since a popular FE103 modification is to wedge caulking compound between the magnet and the basket, I think we can assume it isn't perfectly rigid. I don't see a problem with a light box.

The SL600 undoubtedly had a heavier cone in comparison to the box...

Good call,

I was beginning to think along the same lines as well.

So how much is balsa these days?

[EC8010]

Well, I've just looked, and it's not quite as bad as I thought. A strip 100mm x 20mm x 1000mm was £4.95. OK, so it's much more expensive than MDF, but a composite balsa box will be leading edge technology compared to an MDF box.

[filgor]

Originally posted by EC8010
Well, I've just looked, and it's not quite as bad as I thought. A strip 100mm x 20mm x 1000mm was £4.95. OK, so it's much more expensive than MDF, but a composite balsa box will be leading edge technology compared to an MDF box.

Good work EC8010!

Still watching Dnsey?

It looks like you could be on to a possible winner here.

In the name of experimentation the cost is negligable.

I'm tempted to give it a go myself. I'm working on a centre channel using 4 mid bass drivers that already has more than enough mass. Only problem is that it might be too front heavy!