I have shipped two pairs of speakers with FedEx and have had no problems. I think that the key is in the packaging. Both sets of speakers were in the 90lb/spkr range and double boxed . I received one pair of speakers, shipped through a trucking company, that were banded to a pallet. They were not double boxed and were received damaged .
U-haul sells a large 'wardrobe' box that is double wall thick and works quite well. It accepted JM Lab Electra 926 speakers in their original box's with enough room left for some 3/4" styrofoam wall insulation panels from the home store, for a little added buffering ! Cost was @ $50 for the box's and styrofoam, enough for one pair of speakers . Well worth it IMO . YMMV.
Good Luck
U-haul sells a large 'wardrobe' box that is double wall thick and works quite well. It accepted JM Lab Electra 926 speakers in their original box's with enough room left for some 3/4" styrofoam wall insulation panels from the home store, for a little added buffering ! Cost was @ $50 for the box's and styrofoam, enough for one pair of speakers . Well worth it IMO . YMMV.
Good Luck