Introduction: Modify Your USB Headphones

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Anyone who has ever played video games or watched movies using 5.1 surround sound knows, its pretty darn amazing. However, since those set-ups cost so much money, there are some other solutions to get surround sound on your PC.

5.1 surround sound headphones have been available for several years. Some of them are "USB" so you don't even technically need a sound card to use them. Now, you're probably wondering how you can output sound through USB? Well, you can't. These USB headphones (and all other USB headsets and phones) use a integrated USB sound card that communicates with your PC like an internal sound card would, just through the USB interface.

Sometimes the sound cards are integrated right into the headphones, but sometimes the circuitry is encased in a box that is along the headphone cable. This was the case for the $30 headphones that I bought from Tigerdirect.

What am I getting at? I will show you how you can turn these cheap headphones into two separate devices: a very functional 6-channel USB sound card, and a pair of surround sound headphones you can use with any sound card.

I hope you enjoy reading.

Step 1: How Do Surround-Sound Headphones Work?

Surround sound headphones use three speakers per ear: a Front, a Rear and a Center channel. The center channel is a normal, large headphone speaker. The Front and Rear speakers are more like earbud-style speakers, and are connected to small tubes that guide the sound in front and behind your ear.

The concept is simple, but it requires a 6-channel sound card for it to be true surround sound that is correctly supported by games and DVDs.


Step 2: Materials and Tools

For this project, we need:

Materials:

- USB headphones with in-line amplifier (sound card)
- Project box
- 3x 3.5mm headphone jacks
- 3x 3.5mm headphone plugs
- Red and Black wire
- Small solderable breadboard (optional)

Safety Gear:

- Eye protection
- Ventilated area for soldering


Tools:

- Soldering Iron
- Multimeter
- Drill and appropriate sized bits
- Screwdriver
- Hot glue
- Wire stripper
- needle-nose pliers
- Wire cutter

Step 3: The Sound Card

As I mentioned, headphones or headsets on USB require a integrated sound card to function. This pair has one that is in-line with the headphones, in the middle of the headphone cable. Its not very large, but the headphones are permanently attached to it. We need to change this.

We open up the small casing by removing the screws from the back. We can see many capacitors and a indicator LED. The headphones are connected to the PCB by a single plug. We are going to cut the wire between this plug and the headphones and replace it with three 3.5mm headphone jacks.

Step 4: Identifying Wires

For this to work correctly, we need to identify which wires to go which channels in the speakers.

Open up each side of the headphones. Do this by pulling off the foam ear pads and removing the screws hidden beneath them. Take off the outside shell of the headphones, exposing the speakers.

Take the wire cutters and cut the wire between the headphones and the sound card, about 6 inches from the sound card. We need wire on both sides of the cut, so don't it too short to the sound card. We need to strip the wires on the headphone side. Strip the outer coating to reveal the 8 or so wires. Strip each one so you have about 1cm of bare metal exposed.

Take the multimeter and set it to resistance mode. A low ohms setting will do fine. Put the two probes together and observe what happens on your screen/indicator. It should read near 0 ohms.

Now, take one of the wires at the end of the headphone cable, and place one multimeter probe on it. Place the other probe around on the contacts of the individual headphone speakers. When you have found the right wire, your multimeter will show near 0 ohms. Mark down the color and which speaker it connects to on a piece of paper. We need to chart which channel each wire corresponds to so that we can correctly hook up our connectors.

Do this for all the wires. There should be a common wire for every speaker, but the other wire connected to each speaker should be unique.

Now we need to wire up the 3.5mm plugs so our headphones will be usable.

Step 5: Wiring the Headphone Plugs

We need to identify which connections are which solder points on the plugs. Use your multimeter on the resistance setting again, and place one probe on the tip and the other on a solder point. Keep trying until you find the corresponding one, which will register around 0 ohms.

Mark these down on a piece of paper so you remember which is which. As follows:

The TIP is the LEFT channel.
The MIDDLE is the RIGHT channel.
The BASE is the GROUND.

The jack illustration below is from http://www.ehow.com/how_114206_replace-headphone-plug.html

Take your headphone plugs and solder 3 inch lengths of wire to each connection in them. Solder a black wire to the ground connection and two red ones to the left and right connections.

Solder these wires in place on the headphone cable. Solder all three plug ground wires to the single ground wire from the headphones. The diagram below shows the connections.

When I was complete I encased mine in a small plastic container. A large diameter heat-shrink tube would work well also. Plug each one into a MP3 player, one by one, to make sure they work. You should hear some amount of sound in each ear as you test them. If you're worried about damaging your MP3 player, put your multimeter on each jack connection and the speaker itself, and recheck that each connection is only connected once, and that there are no shorts to the ground connections.

Step 6: The Sound Card, Cont.

Now that the headphone side is done, we can start on the sound card side. What we are doing is exactly the same, except using the female jack instead of the male plug. Wiring is almost identical.

Strip the remaining wire that used to go to the headphones. Strip each individual strand and solder them in a line on a blank breadboard. This will keep things neater and easier. Solder more 3 inch wire segments to the headphone jacks, the way we did with the plugs.

Get a project box that will comfortably hold all these components, and drill holes for the headphone jacks to mount in. Drill a hole on the other side of the box for the USB wire to come out of, if it connects to the PCB by a connector. Make sure the hole is big enough to feed the connector through. If it does not use a connector, either unsolder the wires and feed them through the hole, or use a file to carve a notch in the project box for the wire to rest in.

With the jacks in place, using the wire colour chart we made before, solder the corresponding wires to the correct jacks. The process appears confusing, but if we've documented it well then it will be a piece of cake.

Once thats done, plug the USB connector into your PC. Your PC should recognize it as "USB Audio" and you can use the modified headphones and the Speaker Setup page in the Sounds and Audio Devices section of Control Panel to make sure all the channels work.

If everything is working smoothly, make sure the jacks are securely mounted and close up the box.

Step 7: Complete!

You now have a fully functional 6-channel USB sound card and a pair of 6-channel surround sound headphones. What can you do now that you couldn't before?

- Use any standard 6-channel speaker set on any laptop with USB.
- Use your 6-channel headphones on any PC with a 6-channel sound card.
- Use any headphones on any laptop with better sound quality and less interference.
- Use your 6-channel headphones as normal headphones on any PC, laptop or MP3 player.


At a cost of around $15 for the modification and $30 for the headphones, this project was well worth it for me. Hopefully someone gives it a try from my instructions here. If you have any questions feel free to ask me. Thanks for reading!

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