how to ship a large 160lb subwoofer?

Get a freight company to put it on a pallet; don't even consider UPS or FED EX for this. I had my Gamut L5s in wooden crates shipped on a pallet from upstate NY to Louisville and it was about $240. They weigh 90 lb each not counting the box, carton or pallet. Truck is the only way to go for heavy packages.

I would first set up an account with FedEx (or UPS), it is free and they give members discount. The more you ship the more discount they give, but even first time members shipping for the first time get a discount over the usual rate.

There is also an on-line auction website called 'U-Ship' that I think people bid to ship your items for you. My brother used it to setup shipping his motocycle from California to Washington state.

Put it on a pallet and ship, your gonna have to, about a $1 a pound. May help if you tell us from point A to B.

If you have the original box, that is how the manufacturer shipped it new. To be extra cautious double box it and ship FedEx Ground Freight. As mentioned get a FedEx account set up they are free and they will even pick it up for a small fee. Insure it to be safe.

I used BAX Global freight to ship a big Talon subwoofer. It wasn't cheap, but it wasn't nearly that expensive. I may have had to haave Talon arrange it, I'm not sure they work for consumers directly.