It's a fun but very painstaking process. I think it took me over three hours to get the following shot:Vibrant Motion https://flic.kr/p/9CcBEC
Basically, I went to a local target and got one of those small child paint sets that come with all basic colors individual tiny tubs.
As for the speaker, I personally used my computer subwoofer and covered it with a black vinyl tablecover I got at a local store for like $3.
I got an egg carton and mixed the paint with a little bit a milk (test the ratio to make it less viscous, yet still look like paint) and then use a eye dropper or straw to place on top of the subwoofer.
From then on, it's all about timing. I think I did close to 200 tries before getting something I thought was acceptable.
It's fun and definitely a visually striking, technical photo.. but the most important tool is patience.