HooCanBlog

These are noise reduction headphones, designed for listening to audio while using outdoor power equipment or working in a noisy environment, such as a modern “open” office. They are cobbled together from a pair of hearing protection ear muffs and a pair of inexpensive headphones. The only tools required are a drill, soldering iron, and a knife or small screwdriver.

Please note that you can buy items like this for about $20 more, so if you don’t have the tools it is probably not worth the time. Since I already have a nice soldering station, it was worth it for me for a few reasons. First, I saved $20. My time is valuable, but this was fun to do so I basically got paid to play. Also, the pre-built versions have features I specifically do not want, such as a built-in radio or audio passthrough which allows outside noises to come through at a reduced level. I prefer quiet. Finally, the biggest benefit for me is that they allow me to listen to music at a reasonable level, rather than blasting it to overpower small engines or loud coworkers.

I have seen plans for similar projects online, but what I like about this one is that it requires very little manipulation of the headphone speakers and does not require you to remove the delicate parts from their plastic housing.

Hear are the parts required:

* 3M Tekk Protection Earmuffs, Model 90561, UPC 078371905613 – $24.97 @ Lowe’s, Amazon Link
* Koss KPH7 Headphones, UPC 021299181003 – $4.88 @ Wal-Mart, Amazon Link

Tools needed:
* Knife or small flat head screwdriver
* Soldering iron
* Drill and 3/32″ or 1/8″ drill bit
* (Optional) De-soldering braid and solder
* (Optional) Hot glue gun and hot glue

Steps (Photos below):
1. Disassemble the headphones. The foam pieces can be pulled off easily. After that carefully insert the tip of a knife or screwdriver between the back of the speaker grille and the headband, near one of the three plastic taps. It should snap off easily with a little prying. Be careful not to damage the wires or the plastic grille pieces. The headband and foam pieces can be discarded.

2. Make note of the wire colors and locations, then de-solder them. On mine, the right channel was red/copper and the left channel was green/copper. (This, of course, follows the audio standard of red on the right, but is opposite of the aviation/nautical standard of red/port and green/starboard.)

3. Remove the foam inserts from the earmuffs. They pull out easily and there is no glue or anything holding them in place.

4. Drill a small hole in each earmuff for the wires. The wires are small so used a 1/8″ bit (3/32″ might be large enough). There were some small indentations on the inside of the muffs, so I used them as a guide. This helped me place them in identical locations on each side for a nice, even look. I drilled the holes first from the inside and then again from the outside to clean up the holes. Be sure to remove all of the debris afterward.

5. Untie the knots on the wires, pass them through the holes, and tie new knots a bit further up the wire. The knots provide strain relief and keep the wires from being ripped from the headphones.

6. Solder the wires back onto the speakers. If you are particular about this, you can use de-soldering braid to remove to old solder and replace it with your own. There is plenty of solder there already, though, and the wires are small so it is easy enough just to melt the wire into the existing bead.

7. Carefully reinsert the foam pieces into the earmuffs. Be careful not to put a lot of strain on the wires or solder connections.

8. Tuck the speakers between the foam and red plastic frame. I started mine in the middle and then slid them down to the bottom. The pressure from the foam holds them snugly in place without the need for any adhesive.

9. Optionally seal the outside holes with hot glue.

10. Enjoy the music and spare your hearing.