Getting cold feet on this one.
I don’t blame you. At least three areas of risk.
1) Speakers are damaged while being packaged/prepped for shipment
2) Speakers damaged during shipment.
3) Speakers damaged by the receiver (buyer) in removing them from the pallets, their boxes and setting them up.
One option - Have buyer assume responsibility for shipment.
As the seller, have the buyer have someone; friend, dealer visually inspect and hear the speakers. Close the deal. Buyer then assumes responsibility for coordinating shipment. I would help / do the packing and wait for truck to show up, sign the paperwork. This way if a problem occurs and speakers are damaged, the buyer who has paid for and is controlling the goods, deals with the courier company/broker direct.
Good Luck.
fwiw I bought speakers that were very heavy and loaded onto two pallets at sellers location (Florida) When the truck arrived in my driveway at my house Ontario Canada they were on one pallet !
Anyone want to take a guess what happened....