Best way to ship large / heavy speakers???

I have some speakers I am selling and need advice on shipping. They are about 100 lbs each and measure about 48"x15"x15". I have original boxes w/ packaging material. Anyone with experience or advice to share??? Thanks in advance for your help!
Do a search you'll find lost of info as this has been discussed extensively.
You may want to put some additional styrofoam material inside the box. It can be bought in a 4' x 8', it comes in deifferent thickness. Additionaly you can put shock sensors
and/or tilt sensors to the outside of the boxes, that way the buyer will be able to notify the shipper of rough handling to the boxes. Hope this will help. Hector.
Shipping by Bax Global has worked well for me. I've shipped several pair of speakers in the 200 pound range with no problems.

Good luck!