When I was younger I never had a skateboard but instead I had the best sounding sound system at the beach.
I used a bookshelf speaker that has a long-throw 4" woofer then removed its tweeter and replaced it with a port calculated for the woofer to produce pretty good bass. Then I used two 2" satellite speakers.
I designed and made an active crossover circuit and made a bridged 5W class-AB amplifier for the woofer and the same IC number as a stereo 1.5W per channel amplifier for the satellite speakers. The signal source was a compact cassette recorder/player that I souped up.