they sold me a quarter sheet (2'x4').


A quarter sheet won't be enough to build the entire box out of plexiglas.

If the box were 24" wide by 12" tall by 12" deep, you'd have about .8 cubic feet per speaker (after you subract the volume taken up by the speakers themselves and the thickness of the plexiglas) which is in the ball park for most 10" speakers.

You could build the box out of one 2' by 4' sheet -- except for the two 12" x 12" end pieces. The box wouldn't really have to be 12" deep -- depending on the speakers you use, you could get by with as little as eight or nine inches -- but the plexiglas you save that way won't be in any useful shape or size.

Now if you want to just build a conventional box out of 3/4" MDF, with a plexiglas top in it -- then you can get by with a single 2' x 1' piece, which would probably be more fiscally sensible, and many glass and plastic shops will sell you 1/4 or in this case 1/16 of a sheet.

tanstaafl.