Every time I go to the beach my JBL ends up sitting in the sand. I designed a holder to clamp onto my beach umbrella (21.76mm tube).

Extra Material Used:

1. Three M3x20 screws (one to close/open the clamp, two to secure the clamp to the speaker holder)
2. Two M3 Nuts (one nut goes in the clamp, one I used with the M3 screw to open/close the clamp. I made the M3 version of the Knurled Thumbscrew below)

Knurled M3-M8 Thumbscrews by Elothan - MakerWorld

1. Two M3*10*5 Threaded Inserts (Used in the Speaker Holder that helps screw the Clamp to the Speaker holder.)