Recipe: Take one classic drive-in speaker from the 1960's. Upgrade original tinny speaker element. Add rechargeable Li-Po battery, LED, DW-CT14+ bluetooth module and amplifier. (This nice little board not only connects to the last source, but automatically resumes playing where you last left off, even if paused.) Charges by USB, and the knob is a 3D-printed replica of the original. Voila. The hardest part was drilling out the ridiculously obscure security screws (thanks, Justin) to open the case.