So, a couple of years back I modified some headphones for my eldest son. Basically they were fraying at the plug end so I rewired them with heavier bell-wire, added a right angled plug and covered the whole lot in heat shrink. It wasn't pretty but it made the 'phones a lot better. Until the head band part broke and even Miliput wouldn't fix it. They went to the back of the drawer until middle son, who has Asperger's Syndrome, asked if he could mount the remains of the headphones into some ear-defenders to help stop meltdown in overwhelming situations. Now, he's only twelve, but I'm about to pass the laptop over to him so he can explain how we made them! (We've actually passed the laptop to and fro to collaborate on this Instructable!)
Step 1: Take It All Apart
So first make sure you have the right ear defenders which need foam padding and a dome shape (EDZ kidz .com recommended). We just pulled the foam out of the middle, then scrunched up the ear-padding and took out both the screws to remove the plastic ring. Then you get your headphones (make sure that the wire splits into each ear) and take them completely apart. We compared the plastic inner for the headphones to the ear defender parts to see how it would fit. We made a template (measure to make sure that its correct), aligned the plastic speaker with the drawing and cut holes for the screws.
Step 2: Cut It
Take out the the thick foam padding and with a saw cut a hole in the ear defender just big enough for the wire and grommet. We had to cut notches in the speaker covers so the screws would fit around them. and replace the padding but not the ring. Insert headphones speaker cover you cut to size then add the speaker and then the ear padding and screw it all down. Now you've done one ear repeat on the other side
Step 3: Assembly
We just put it all together, with the wire through the notch and the speaker in the cover. Did take about three hands to hold it together and scrunch the foam cover out of the way. As you can see from this final photo our twelve year old Middlest child is very happy and they look very neat and unobtrusive. They also cut down more outside noise than normal headphones and he knows they'll be really good for sensory overwhelm meltdown situations. (He also agrees with our policy about having his photo on the Internet!)