Is B&Q plywood good enough to make subwoofer boxes

I was wondering, is B&Q 18mm plywood good enough for using to make sub enclosures? Because baltic birch plywood is well expensive. Oh and is mdf bad because it has a tendancy to resonate more easily?

MDF is more dense and inert, so it would resonate less.

It's not very useful because of its weight and strength.  It doesn't hold screws very well, can split easily,  and susceptible to water damage.

I get good quality play from my countries equivalent of B&Q.  It varies depending on which store you go to.  They seem to get wood from different suppliers.

I got some of the 18mm ply from B&Q, around £27 a sheet. It was 5 ply, with an extra thin veneer on each side for appearance.

I know the local woodyards in my town aint got nothing in wothy of making a high power sub enclosure. B&Q in my town has 18mm ply but I think its only 5ply.

Ok thanks. How would I make the grille?  Do you guys know of any box design software that would enable me to print out a detailed plan of the enclosure? I know the internal volume from using WinISD Pro and the internal dimensions from using Speaker Workshop but have no idea about how I want the cabinet to look. The driver i'm gonna use is the RCF LF18X400 and have the box tuned to 30hz seeing as the RCF driver has a resonant frequency of 28hz.  

Edited by richard stringer - 04 January 2009 at 7:50pm

I used B&Q's Brazilian Ply (Palmaply?) to build the ported horns.  It's definitely not void free but it did the job, is lighter than birch ply and a whole lot cheaper.  I wouldn't recommend it for cabs which will be used regularly but for prototypes and cabs you're only going to use occaisionally.  You need to use a bit more bracing than you would for birch.

Probably better is to use the 7 ply hardwood WBP exterior ply.  Again not as good as Birch but will still make solid speaker cabs if you can't afford Birch and don't like MDF.