Now I guess it's spoken by not responsible company that doesn't cover fault of their own solely. If solid wood isn't dry enough, than it will eventually crack with or without extraneous force applied. I may make a not of their discusting customer service.
In your case I'd arm myself with epoxy mix, blanket, huge vise to grip the whole speaker and some prayers so the rest of wood planes are dry enough not to crack under moderate pressure(just to be enough to hold this cabinette for 24hrs). Vise is purchasable in Home Depot and if you won't need it for other projects you can return and get your money back right after using it.
In your case I'd arm myself with epoxy mix, blanket, huge vise to grip the whole speaker and some prayers so the rest of wood planes are dry enough not to crack under moderate pressure(just to be enough to hold this cabinette for 24hrs). Vise is purchasable in Home Depot and if you won't need it for other projects you can return and get your money back right after using it.