From: Hows this box sound?

[NB50 206]

I'd be wary of that design it doesn't quite add up right. Just at a quick glance the port width is 5" but at the back wall it is only 4.5".

Its 4.5" LENGTH after the corner of the port. Not width. It's stilll 5" wide.

Nice design!

Not talking about the length that is given.

15.25" port wall + .75" for the second wall = 16"

20.5" of internal depth - 16" = 4.5" away from the rear wall.

Not to mention if it was 5" from the back it would be tuned to 34hz