50% down to ship, balance On delivery. Package within package, expanding foam
@ all corners with plastic to keep foam off original carton(s). Air 'pillows' @ the sides, backs.
Heavy speakers should be on a pallet, with a wood frame about the boxes.
Label 'NO STACK', 'FRAGILE-GLASS' loudly labeled all sides.
Any idiot in a shipping facility knows if it's speared with a forklift, the company just bought it and your job is toast.
Insure it for it's value; the real one.
Your object, your risk. Become bullet-proof.
If it's heavy the shipping method should reflect that.
BTW, They Pay for the priviledge....