I ordered a Dayton Audio DTA-1 battery powered amp, a pair of Dayton Audio DAEX25 exciter speakers, and the cooler I wanted to transform. I had some other hardware on hand such as zip ties, mesh wire cover, heat shrink tubing, adhesive velcro pads, and wire. Construction is super simple. I put four velcro pads on the amp and fixed it to the cooler. I peeled off the backs of the adhesive pads on the speakers and mounted them on as well. I cut some wire to length, tinned the ends with solder to prevent fraying, and covered the pairs in a plastic cable cover mesh.

The cooler sounds great and is plenty loud for outdoor gatherings. I'm very happy with how this turned out and at ~$40 in electronics, I think it's a great value.