DIY Super-Noise-Canceling Headphones

This Instructable will teach you how to make noise-canceling headphones that do a better job than even the most expensive brands, at a small fraction of the price.

I just moved in to a new apartment for the beginning of this school year.  I like my apartment a lot; it is very modern, it is big, I think it is fairly defensible in case of a zombie apocalypse, but there is one problem:  there is always a lot of noise.  Between the TV being on all the time with high volume, and people constantly chatting, and sounds from the kitchen, and noisy neighbors, it can be difficult to get some peace and quiet.

So, in the interest of being able to listen to music, relax, and, of course, do homework, I started shopping for noise-canceling headphones.  Unfortunately, noise-canceling headphones can be quite expensive, especially high quality ones.  Brands like Bose, Sony, Audio-Technica, and Sennheiser can cost in the neighborhood of $300.  Since I don't have that kind of money to spend on headphones, I decided to make my own.

This Instructable will show you how to make headphones that block just as much noise as those high-end brands I just mentioned but cost less than $35.  Plus, the process is really easy.  Let's get started.

Step 1: Parts

General Parts List

You will only need two things for this Instructable:

1. A pair of headphones
2. A pair of hearing protection earmuffs

Specific Parts used in this Instructable

In case you are interested in getting the exact parts I use in this Instructable (it might make following the Instructable a bit easier), here they are:

1. iHome iB40B Over-the-Ear Headphones with Volume Control, Black
2. Howard Leight R-01523 Leightning L0F Ultra Lightweight NRR 23 Compact Folding Earmuff

Step 2: A Word About Noise Reduction

If you just want to build your headphones and are not interested in the science involved, you can just skip this step.

You might be wondering, what exactly makes some noise-canceling headphones better than others?  Well, there are two parts of the answer to this question.

First off, there are two different technologies used in noise-canceling headphones:  active noise-cancellation and passive noise-suppression.  Active noise-cancellation headphones eliminate ambient noise by creating their own sound waves that mimic the incoming noise in every respect except one: the headphone's sound waves are 180 degrees out of phase with the intruding wave.  Basic physics tells us that two sound waves with the same amplitude that are 180 degrees out of phase will cancel each other out.  In order to detect, analyze, and cancel out incoming ambient sound, active systems use some fairly sophisticated electronics.  This is what makes headphones featuring active noise-cancellation technologies so expensive. The technology is admittedly very good at reducing ambient noise.  Unfortunately, they are not very good at canceling more dynamic noise, like talking, TVs or other music.

Passive noise-suppression is much simpler than active noise-cancellation and it is the technology used in the headphones we will be making in this Instructable.  Passive noise-suppression blocks noise simply by placing sound-absorbent materials, like foam, between the noise source and the listener's ears.  Although passive systems are not as efficient as active ones at reducing ambient noise, they do have a couple of advantages:

• Passive systems are much, much cheaper than active ones.
• Passive systems can be better at blocking dynamic noise like TV's, talking, or dog barking.
• Passive systems do not require batteries.
• Passive systems are usually more durable than active systems.

So, how exactly can a person analytically compare the noise-reduction capabilities of different headphones?  Well, as it turns out, there is actually a way to measure noise reduction.  It is called the noise reduction rating (NRR).  A headphone's NRR is a measure of the how much quieter the noise inside the headphones is than the noise outside.  NRR has units of decibels (dB), a unit which expresses (kind of) the volume of sound.  Standard ear plugs - those yellow ones that you squish and stick in your ears for them to expand - have a typical NRR of 29dB (which is actually really good).  That means that the inside of a factory produces 80dB, the noise heard by a person wearing ear plugs would be 51dB (which is eighty minus twenty-nine).  Note though that this measurement is for passive systems only.

Even very good noise-canceling headphones have a noise suppression rating of about 20dB.  The headphones we will make in this Instructable have an NRR of 23dB, so for passive systems, it is better than all but the most expensive headphones.

Step 3: Remove the Ear Pieces From the Earmuffs

The entire goal of this Instructable will be to combine the noise-blocking earmuffs with the music-producing headphones.  The first step in this process will be to remove the ear cups from the earmuffs.  This is fairly simple.  Just cut off the fabric covering on the headband, and pry the metal bands on the ear pieces off.

Then, remove the swiveling metal brackets from the ear pieces.  This can be quite tricky since these pieces are very tough.  I suggest cutting the metal wires and then prying the plastic parts until they pop off the ear pieces. 

Step 4: Disect the Headphones

Now you will need to remove all of the housing material from around the speakers in the headphones.  This will require a couple of steps:

1. Pull off the foam ear cushions from the headphones.
2. Pry off the plastic grills to which the speakers are attached.  Do this carefully because the speakers have little thin wires attached to them that can get ripped off easily.
3. Remove the screw that attaches the remaining portion of the plastic speaker housing to the headband.
4. Cut the other plastic parts in half so that the headphone cords can be taken out and the plastic portions discarded.

Finally, you should have just two speakers wired through the headband.  Again, be careful because the speakers are attached with fragile wires.

While you are busy disassembling things, you should also cut the netting off the ear pads that came off the headphones.  We will need this part later. 

Step 5: Prepare the Earmuff Ear Pieces

There are a couple of things that need to be done in order to prepare the ear pieces on the earmuffs to be attached to the headphone head band and accommodate the speakers from the headphones:

1. Remove the ear pads from the ear pieces.  It simply slips into tabs in the interior edge of the cups.
2. Take the foam out of the ear pieces (but save it).
3. Drill a hole through the center of both ear pieces.  This is where we will screw the ear pieces and the headband together.
4. In both ear pieces cut a notch in the side.  This is where the wires from the speakers will enter the ear cups.
5. In the left ear piece, cut another notch in the bottom for the signal cord.

Step 6: Assemble Your New Headphones

It is finally time to assemble the headphones. 

1. Screw the ear pieces from the earmuffs onto the head band from the headphones. 
2. Reinsert the foam into the ear pieces. 
3. Place the speakers into the ear pieces with the wires going through the notches.
4. Place the black cloth from the headphone ear cushions on top of the speakers.
5. Hold it all together by replacing the ear cushions from the earmuffs back on.

Congratulations, you are done!  Go turn on some music and enjoy!