Matt: plywood was commonly used in the 50s and early 60s.. companies switched to MDF because it was denser. a 1/2" thick MDF box will produce less noise then an equally built 1/2" plywood box.
This is why you never see plywood cabinets on ANY house speakers, especially expensive ones. I assure you they can afford plywood on a pair of $5-30K speakers. They all use MDF or HDF board.
I'm not sure where you have seen quality home enclosures made from plywood. Have articles? Only cabinets I know made from plywood are commercial\PA cabinets. And its because they are durable when it comes to abuse. Not sound quality.
