Hi guys - I know this should be in the fabrication section, but i think it lends itself more towards a sq oritentated discusion.

Are there any disadvantages (sq wise) to constructing a sub box from fiberglass as opposed to your traditional mdf?

Also, in regards to accurately calculating enclosure volume, how would I go about doing this (apart from filling with water!)?

Only reason I would be using fiberglass is so that I can negotiate tricky curves in my boot and angle itso that I have 100% functional access to my spare tyre.

You can try bean bag filler when calculating the volume.

I'd use something larger than bean bag filler myself, as it sticks to everything due to luuurvly static forces. Those foam bits from packing places are good.

As long as the FG layer is thick enough not to have problems with flexing, then there is no problem. Make sure its braced (right angle MDF ribs are great) and if your really worried about the lower mass having resonance, use paint on SD or make it thicker.