I decided to build hard-case transport boxes to protect my new Jazzman Mk III speakers during the annual trek to Carverfest. The hard cases can be carried in the back of my truck, even if it's raining.
The cases are two-piece interlocking clamshells made from light-weight 3/16 plywood painted with truck liner coating. The clamshells snap together with (6) draw latches and a foam rubber gasket between them seals out the rain. The bottom clamshells have carrying handles on each end, for two person carry.
Interior surfaces which contact the speakers are Styrofoam covered with synthetic felt.