Introduction: Sony MDR-7506s Inside 3M Tekk 30db Noise Reduction Earmuffs
Mark has been wearing these noise canceling earmuffs with ear buds. The noise reduction is amazing but the earbuds always get a little dislodged when you put the earmuffs on. It got me wondering what it would be like to put a larger driver inside the earmuff like an MDR-7506 . I had an old pair lying around so I gave it a try. The results work great. You get the 30 db noise cancellation combined with the high quality MDR-7506 driver. Here's how you do it.
Step 1: Remove the Drivers
Gently pull off the foam covers. Unscrew the 4 screws and pop the drivers out by pressing in the 4 angled tabs on the back side. Desolder the drivers. Unscrew the 4 screws on the inside of the headphones. Remove the cable that goes from the left side to the right side of the headphones. Remove the "telephone" cable with the mini- stereo connector from the headphones. Gently peel the foam ovals from the foam rings. You'll need these later.
Step 2: The Rest
Take a coat hangar and cut out a nice straight section. File the sharp end down where you cut it making it blunt. Bend it on roughly the same curve as the earmuff's wire. Thread it through alongside the wire for the earmuffs. When it comes out the other side bend a small hook out of the end. Cut the other end off leaving a few inches to work with. Cut the wires off the ends of the thin cable that went from left to right on the headphones. Cut very close to the end. You don't want to lose too much wire. Tape one of the wire to the coat hangar using clear tape. Make sure its nice and tight. Start about a half inch on the hangar and finish about a half inch down the wire. Use the hook to pull the wire through to the other side of the ear muffs. Remove the soft foam from inside the earmuffs. It is not glued in and comes out easily. Drill two small holes in the sides of the earmuffs. Make them as close to the size of the thin wire as you can. Use a paper clip to clear the hole (there's foam in the earmuffs that likes to get in the way). Push the wires through the holes. If your holes are nice and tight this is a pain in the ass. Good luck. Otherwise drill bigger holes and seal with black silicone if you are lazy and like ugly silicone blobs. Drill a big hole for the "telephone" cable in the bottom of the left side. The MDRs keep the left to right cable towards the back so pick your left side accordingly. Thread the telephone cable through the hole and tie a knot in it so it can't pull through. I put the rubber sleeve back on it too but it didn't fit well in the hole I had made. Re-solder all wires. Put the foam back in the earmuffs. Put the drivers in. Take the thin foam from the inside of the MDR earmuffs and use it to trap the driver in place between the big foam block and the thin foam. Listen to Koyaanisqatsi and block out the buzzing world with your super noise reducing earmuff headphones.