Casting material for a small speaker box

[oon_the_kid]

Hi,

I though of casting up a small speaker cabinet for a 3" driver probably about 1 litre inner volume.

I am planning on using potting compound that were originally intended for electronic compounds, as they tend to be soft which would suggest better damping properties. However they are not cheap, so I intend to add in some rough sand or large pebbles to act as fillers to form a composite of resin and rocks/sand. Giving it weight and damping.

The question is, which do you think will do a better job of damping, bigger rocks or smaller rocks (such as rough sand).

Thanks.

Oon

 

[Bill poster]

intend to add in some rough sand or large pebbles to act as fillers to form a composite of resin and rocks/sand. Giving it weight and damping.

The question is, which do you think will do a better job of damping, bigger rocks or smaller rocks (such as rough sand).

No expert, but you could try powdered marble (from art shops)

 

[wintermute]

This might give you some ideas This is a guide to using acoustic concrete.

Tony.

 

[Nico Ras]

Use kitty litter

 

[W0J0]

I'm not sure what specific products are offered in Singapore but here in the states, Custom Building Products offers a product called "custom float". It's a lightweight concrete with expanded polystyrene(Styrofoam) beads in it. When mixed just a little dry, it's easy to pack into a form and put a nice smooth finish on.
The other idea I had was to use a foaming agent and create aerated concrete. Basically the foaming agent gets whipped into a consistency like dessert cream and is then added to a sand cement mix where it entrains air bubbles in the finished mix, keeping the concrete light and fluffy.
A combination of the two may yield even better results. Add some reinforcing fibers and you should be able to cast as thin as 12mm.

 

[oon_the_kid]

Thanks. I did think about concrete. But I reckon it will ring at fairly high frequency. So that's why I am trying out electronic potting material.