Step 1: What you need
a small speaker(about the size of you ear)
and old audio jack
a soldering iron
a needle and thread
and of course and old beanie
Step 2: Time to D.I.Y.
2.Then tape the exposed wire with electrical tape.
3.Next remove the threads the open a hole in the beanie.
4.Then insert the speaker assembly.
5.Finally proceed to sewing the hat back together.