I've made cabs out of true Baltic Birch, i.e. thick veneers and about 11 plys all of which are birch. I've made cabs out birch and oak veneer ply also, i.e. thin veneers with inner plys made out of soft wood with maybe 7 plys. No question the Baltic Birch is stiffer and definitely much heavier. That said, I've made great sounding cabs out of both Baltic Birch and regular big box plywood. In a blind fold test, I doubt the average musician would be able to pick them apart.