- One or more wireless headphone sets with rechargeable bases (we used inexpensive Sony RF headphones)
- A soldering iron
- Two channel socket and plug connectors for power
- A miniature slider switch
- Some thin cabling
- Plexiglas and hot glue or other material to build speaker housings
- A dremel or similar to make openings in the speaker housings
Step 1: Modding the Charging Base
First open the recharging base of the wireless headphone set. Our unit had five screws underneath.
Step 2: Choose a Speaker Set-up
Next, for the headphone to speaker mod, there are several choices.
1. You may choose to have both left and right speakers in one housing with all of the charging circuits and batteries. (This example is pictured below:)
3. You may want two separate left and right channels in separate housings with separate batteries and circuitry. For this example you will need two sets of headphones. You may choose to place two sets of drivers in each channel's housing. (This example not pictured because it is the same as Example 1 except there are two speakers instead of one.)
4. Maybe your Burning Man friends are putting on the pressure for multichannel audio in your mod. In this case, you can buy six sets of the Sony headphones. The Sony model of cheapest RF headphones has a selector for three different radio channels on the back of the base. In theory this means you can send three sets of stereo which equals six unique channels of wireless audio out. (See drawing below:)
Step 3: Modding the Headphones into Speakers
Take apart the headphones by unscrewing all the screws and popping open the housing. Try to keep the cables between the two sides of the headphones intact. If you need to cut the cables to remove all the circuitry, simply do so and resolder the connections later. Cut the battery housing down around the batteries with a dremel or small plastic cutting saw but keep it intact as well. Create a small plastic box from Plexiglas and first cut a hole large enough to access the batteries. First pictured below is Example 1 with both drivers in the same housing, then Example 2 with one driver in each housing:
Cut a small rectangular hole out of the housing for an on/off switch. This needed to be soldered in place of the spring-based momentary switch in the headphones we used. Our headphone model turned on when the inside band of the headphones were pulled by the shape of the wearer's head. We replaced this with a sliding switch which we then glued into the housing:
Next cut a hole in the Plexiglas box large enough for the speaker housing. Remember that the speaker should be fairly well sealed for resonance purposes. Viewed from the inside, the speaker glued on the hole looks like this, below:
Now solder the other end of the power connector (the female end that fits the connector on the wire now sticking out of the charging base) to wire. Solder the two wires of the power cable to the charging tabs that were in the headphone housing. These tabs were the ones that came in contact with the charging springs when the headphones were placed on the charging base. Two views of the power connector (ours in this case is large and white in the photos) follow showing the tabs where the wires were soldered.
Now test your speaker(s) with your system's base with audio to make sure you haven't forgotten anything. Repeat the steps above for each speaker in your system. You may want to glue down the channel selector dials on the speaker side if you decide to go the multichannel route. Also the volume dial on our sets have been glued to maximum for applications where the speakers are in a public setting. Alternately you may wish to cut rectangular holes in your speaker housing to access the volume and RF channel selection potentiometers.
Some other further development for you electrical engineering types can include creating audio outputs for better speakers and gain stages instead of speakers on the receiving end. Be creative! This How-To is by no means meant to be a finished creative entity.
Leave us feedback if you send some of these bad boys up in balloons in the high desert.