I'm an amateur woodworker also but I build horns. Still the basic idea of eliminating resonances holds true. If the box is properly braced it should not matter much what it is made of. I would only be concerned about dimensional stability with the use of hardwoods alone. This is especially important for the baffle that the drivers mount to. Most chose to build the cabinet frame using void free plywood, or MDF, and then laminate the hardwood on top. Not only does it give a beautiful finish but if you go 1/4" or thicker it adds stiffness. I'm not saying it can't be done with all hardwood, but I know I sleep better knowing my seams and surfaces are going to stay tight.
Good luck with the build.
Good luck with the build.