I'm sure some of you are like my and still have the old behind the head headphones that were all the rage a few years ago. and, like me, the pads are probably falling apart. instead of buying new headphones, here's a super easy, super cheap way to fix them!
all you need is a needle, thread, and some craft felt. your felt should be fairly soft, fairly porus, and not prone to pilling. (the sound quality for me has been at least as good as through the original foam) you probably want to match your felt and thread color unless you like the contrast stitching look. they hold up fairly well - mine survived for almost a year of daily use (and sometimes dragging on the ground behind my backpack) and could have held up longer except that I wanted to do this tutorial.
Step 1 - take off the old foam pads.
Step 2 - cut out two circles of felt slightly larger than the earpieces (for my sony street style headphones, I cut them about 3" in diameter)
Step 3 - fold the thread in half and knot the end. do a running stitch around the edges of one of the felt circles, pulling the thread through the knotted end.
Step 4 - place the circle behind the earpiece and tighten the thread slightly. see how it's starting to "grab" the sides of the earpiece?
Step 5 - tighten the thread and knot it off. cut and hide the thread so it doesn't stick out. repeat steps 3-5 on the other side with the other circle.
Step 6 - yay, you're done! admire your good-as-new headphones.