Seller Question - I need UPS to come get these large speaker boxes - how to manage that?

Do not ship large speakers through UPS or FedEx ground  unless they are in wooden crates. You are taking a risk and it’s a 50/50 chance that they will get to their destination in one piece. Both UPS and FedEx are not equipped to handle large packages. For large speakers, always use freight with speakers tied to a pallet or offer local pickup. 

Please note, there is FedEx and FedEx freight. Same with UPS - there is a weight and size limit for UPS and FedEx - you might put the speakers on a shipping pallet (skid) Pallets come in different sizes so choose a size which will accommodate the speaker boxes, but not too big as that raises your shipping costs. You'll need to strap the boxes to the pallet and I would wrap the boxes with a vinyl wrap to protect the boxes from moisture. You need to give FedEx freight the dimensions and the weight of the pallet. Some sellers need to pack the pallet outside their house - this is not a service that FedEx does for you. You might have to pay for a tailgate at both ends and there is usually an extra charge if you are collecting or shipping into a residential address. You'll be shocked at the cost of shipping.

Depending on the size and weight, you might want to consider using a common carrier.  I have used Estes several times with good results.

All the best.

If possible, if you want to palletize the speakers, make sure you pack them on their sides with the speaker cones facing each other and that should at least protect them. Make sure you plastic wrap the entire pallet before shipping. 

I’ve shipped large boxed, high value speakers, electronics (RTR player, amplifiers), rare tubes, and turntables using a white glove delivery service (aka courier service). Several choices are available online; will transport across CANUSA); and insured. They are more equivalent in price to the commercial shippers using pallets, but I offer it to the buyer as an option and incorporate it into the sale price.