Introduction: How to Hack an Etymotic ER-6iPhone Headset

{an instructables debut.}

You love your Etymotic ER-6i headphones. Mine decided that the plug should start being sketchy, leading to me having to gaffer tape them in a specific orientation to keep sound going in the left ear.

At the same time, my iPhone headset earbuds started to get a little "meh" (ie. rubber coming off the earbuds), and I missed the sound isolation of the ER-6i in the BART transbay tube, since I was using the iPhone headset for the convenience of the remote. (I used to have an old iPhone, but the new one doesn't have the same headphone jack problem so that's a moot point.)

Thanks to this flickr set by jeffb, my main resource. I also referenced this video.

Step 1: Supplies!

You will need:
Etymotic ER-6i headphones
Apple iPhone Headset
3/8" diameter, 2:1 or 3:1 heat-shrink tubing (found at a hardware / electronics store)
(alternatively, you could probably just use electrical tape or something, but I didn't try it)

a soldering iron (with thin / fine tip)
a heat gun (or alternatively, a stove, or high power hairdryer and the corner of a box?)
scissors / knife / xacto / diagonal cutters (various sharp implements)
maybe some small needle-nose pliers... (or nimble fingers).
a pen, with a thin tip.
1/16" drill bit (depending on your patience)
maybe some sticky tack to hold stuff (see step 8)

Step 2: Open Up the ER-6i Headphones

Here goes!
First, pull off the earpieces off of the ER-6i. Then, remove the small plastic cable stress relief, using your fingernails or a thin pen to pry it off.
Now, cut off the plastic wrapping over the main body of the earbud. All you need to do is make a small notch, and then you should be able to peel it off in a spiral (with your fingernails or with needle-nose pliers).

Step 3: Disassemble the ER-6i Headphones

Use a pen to pry off black (or white) housing from clear portion. Do one side, then the other, and wiggle it off. Pull on the clear part lightly to unstick the wire glued to the inside of the black housing, and then pull the cable up and through the housing to give it more slack. You can untie the cable now too, if you want.

Step 4: Open Up the IPhone Headset

{you might want to heat up the soldering iron at this point}
To open up the iPhone headset, take a knife, or a scissors blade, and press down and twist right on the border between the white plastic and rubber ring. Pull them apart, and then pull slack and untie the cables. Be sure to do this carefully and don't slip and cut yourself!

Step 5: De-solder IPhone Headset Earbuds

Now, while carefully holding the earbud, pull on the cable lightly and touch the soldering iron to the contacts. It may take a little while, but if you find the "hot spot" of the iron, they should come off with a short touch. If you can't seem to get it off, rotate the tip every 10ish seconds until you find the hot spot. 

Step 6: De-solder ER-6i Earbuds.

This one's a little more tricky. Same technique, just be very careful that you don't melt the plastic housing of the earbuds while you're de-soldering. It helps to know the hot spot (I kept using the old iPhone drivers to test by re-melting their solder to find it), so that it takes the minimum amount of time. This can be one of the more frustrating parts of the process if you're like me and had a lot of trouble finding it. I would tell you to worry about which color wires went where, but I remembered it for you :)
When you're done, just untie and pull the wires out of the black part of the housing.

Step 7: Prepare to Re-solder

Now, you need to thread the iPhone headset wires through the same way. The white cable housing on the iPhone headset is a little larger, so you can either be *really* patient and wiggle it through (don't pull on the little wires, they don't help to pull the housing through), or, you can make the hole bigger. Use the 1/16" diameter drill by hand to enlarge the hole. This makes it way easier. See the pictures for correct threading: you want to go up, then inside the earbuds.
Next, tie a knot. leave about 2-3 mm of housing on the headset cable before the wires are exposed. Too much and it won't fit back together; too little and it won't relieve the stress.

Step 8: Solder

Start on the Left earbud, and the wire with the green- and copper-colored leads. Green lead goes on the "L" side of the earbud, copper lead goes on the "er-6i" side.
On the Right earbud, The red lead goes on the "er-6i" side, and the copper lead goes on the "R" side.
Carefully hold each wire on the correct contact (with your nimble fingers or pliers or whathaveyou), and touch the soldering iron to solder it back on. There should be enough solder there, and if you've got the hot spot thing down all you should need is a brief touch. Again, be careful not to melt the housing (oops, I did a bit), or accidentally touch the cables.
When you've got one on, go ahead and test it to make sure the solders are good.

Step 9: Assemble

Now that you have the earbuds soldered on, all you have to do is re-assemble them. If you had too much cable at the end, go ahead and shorten it by adjusting the knot. Now, pull the cord back through the black part of the housing as you push the clear plastic part back into it, but make sure the the cord is oriented correctly: the leads on the clear part should point downwards, and the cord should leave the top of the black housing. (The cord should go from the bottom of the clear part, to the top of the black part, then down again through, and out. See the pictures.) It might take a little effort, since the cable is a little larger and it'll be a tight fit.
Once they're back together, put the earpieces back on, and test them out!

Step 10: Heat-shrink

Almost there! To make sure they're secure, you want to shrink wrap them. Technically you could probably skip the heat-shrink tubing, and use some tape, or string or something instead, but it would look a little meh. I only could find black heat-shrink tubing, so I have black earbuds, which look a little weird, but I'm okay with it for now. If you want, go ahead and find whatever kind you want...
Before you shrink wrap, take off the earpieces again if you were testing, and then cut the heat-shrink tubing so it's the right size for the earbuds, about 12mm long. For cable clearance, cut a corner off, about 1mm down from the corner. Then, slide it over the earbud, and line up the cut out corner with the wire.
Hold the earbud up by the wire, or with pliers, and apply heat with the heat gun, or slowly over the stove. I had the luxury of access to a heat gun, but I've read that stoves work fine, just hold it high above the burner at first so you don't melt the cable housing. (I've also heard a 1500W hair dryer could work, if you concentrate the air at it, like in the corner of a box.) It doesn't need to be burning hot, and it's pretty amazing how well it works. Try to get an even distribution of heat on all sides so it shrinks evenly and has a snug fit. If you're me, cut it off and do it again, since the corner cut was way too big the first time.

{only one more step! this one goes to 11.}

Step 11: Rock Out.

Sweet! You have successfully frankenstein'd your ER-6i's onto an iPhone headset! Beautiful. Now go enjoy some aural bliss.
with luck,