Shipping co. recommendations (CHI -> SF)

What size are the speakers? If these are bookshelf then you can probably pack them well enough yourself to withstand the torture that UPS and FedEx will inflict via normal dropping and conveyors.  For floorstanders I highly recommend shipping via freight with your boxes strapped onto a pallet so only fork trucks handle it.  I'd contact a freight broker like these guys to see what are your options are. 

https://www.freightcenter.com/

Fourteen years at Airborne Express here. Shipping is way more technical than you seem to know. There is about as much chance of telling you how to ship these without knowing weight and dimensions as telling you where to put them to sound good when they get there.