......Fender advertise Supersonic cabs as 13ply Baltic Birch Plywood construction....the front baffle is, but the rest is particle board.
Buyers beware of false statements.
Most consumer amps (from fender, marshall and peavey and others) and cabinets are build from particle board. The vast majority of players don't know and don't care.
I prefer pine for my cabinets. Pine has both a high pitch and a low pitch when you knock on it as compared to both baltic birch ply and particle board. I guess thats why it has a wider frequency spread.