I'm sure this has been asked before somehow, but...(Fostex BLH construction question)
 

As we all know, Fostex's recommended plans are designed for 15mm lumber...and in the US, we're stuck with inches and feet. Has anyone built a Fostex backloaded horn design using 5/8" stock...would this even work with the slight difference in thickness? Or is it small enough not to make a difference...

Thanks in advance. :smash:

If you use MDF, don't you have the right metric thickness? Or baltic birch for that matter? I think what we call 1/2" baltic birch is really 15mm, but I could be wrong. When I build some speakes to metirc dimensions I bought a nice metric steel ruler and used that - it was surprising how quickly I adapted from inches to mm.
Steve

Modifying the thickness of fractions of small units basically doesn't affects the sound that much. I'd rather say the materials thewselves have more importance than the small dimensions variations, as Fostex BLH are not anyway ultra-optimsed.

Hi jim_vt,

This web site helped me a lot http://www.sciencemadesimple.com/conversions.html

15mm is .59", 5/8" is .63". There is .04 diff. So, 15mm looks closer to 5/8" than the 1/2" ply-wood. The 5/8" thick ply could actually be a bit thinner than advertised. hope this helps

John

Best measure your plywood. It is notoriously variable in its thickness from maker to maker.