question for matt h

[suprastorm]

how would you work out the box size for a fibreglass box ?

[Matt Harwood]

With difficulty!

TBH, I've never done it, but I've been told, you can either do it with drysand, (needs a severe hoover afterwards I'd imagine), or polystyrene balls like the type you get from beanbags.
Using a litre measuring jug, poor measures amounts of the above into the box to see what your box size is.
If you need to make the enclosure smaller, fill it with a dense material like a chunk of wood, if it needs to be larger, add more wadding.

Sorry I can't be more precise, as I said, I've never done it. All the firbreglass enclosures we buy are generally made to measure. All the ones we make are rough guesstimates based on an aproximate box size. Always sealed, that way you have a much greater chance of getting a good sound.

HTH

[suprastorm]

thats what i was going to do , just wondered if there was an easier way really. sand would be more acurate i suppose. ive been cheating by making the box first then a lid , but your quite limited with the shapes you can make .

Thanks ill let you know how it gos.

[Matt Harwood]

I'd go with sand as being the more acurate measure. Personally, If I were going to do it, I'd make sure the sand was totally dry, then after you're finished, re-coat the inside with another layer of fibreglass resin. That way you won't have any small bits of sand kicking around to get caught up in the subs voice coil:eek: