Easy way to make FBI-escque earphones. This is very useful if you ever want to listen to music but also have one ear free (for instance while biking in the city)

Step 1: Cut Up an Old Phone Cord

Cut the ends off an old springy phone cord.

get some earbud headphones, cut the earbuds off and cut the jack off.

you will need:

1 earbud
1 jack (stereo or mono)
1 cut phone cord
multimeter
soldering iron

Step 2: Solder Everything Together

#####################################################
NOTE:
Some commenters have noted that it could be dangerous to your audio player to follow this instructable's instructions, mostly if you try to do it with a mono vs. stero jack.
I did this with a stereo jack and an ipod, and it worked fine, I've been using it for a long time, full volume, etc, no problems. So if you have an ipod and use a stereo jack it should be safe to follow this instructable. With other audio players it might work ok too, but who knows.
#####################################################

The diagram explains it all, the text might be hard to follow. To see the diagram more clearly click here TO VIEW IT FULL SIZE:
https://www.instructables.com/files/deriv/FQW/WZCS/20REQ6T27TZ/FQWWZCS20REQ6T27TZ.LARGE.jpg

using a multimeter figure out which wires of the headphone jack connect to the two segments closest to the tip (or the single segment at the tip if it's a mono jack instead of a stereo jack).

solder both (or a single wire if it's a mono jack) of these wires to a single wire of the phone cord.

Solder this same phone cord wire, at the other end of the phone cord, to the wires (or wire if mono) on the earbud side which are the same color as the jack side.

solder the ground wires of the jack side to a single wire of the phone cord.

Solder this same phone cord wire to the ground wires of the earbud.

Step 3: Check for Continuity

check that the wires are appropriately connected using a multimeter. Make sure that there is resistance between the non-ground and ground wires (this resistance is the internal resistance of the earbud through which the wires are connected).

If everything checks out, plug it in and have fun.