DIY Audio Mixer

You don’t need to buy an expensive mixer to mix your sounds. This graphite mixer requires only a pencil, a sheet of paper, and a few wires!

(and two iPads if you're so inclined...)

Parts You’ll Need:
-Audio sources (whatever it is you want to mix)
-Alligator clips
-1/8” Audio cables
-Wire
-Speaker or headphones
-Regular graphite pencil
-Paper
-Electrical tape (optional, but recommended)
-1 or 2 y-split cables (optional, for stereo)

On your sheet of paper, outline the shape that you want your mixer to take. When designing your shape, keep in mind the path the signal will have to take from source to speaker. The shape shown is great for four-channel mixing.

Fill in the shape with a graphite pencil. Make sure to press hard and apply several layers. The graphite must be thick enough and continuous in order to carry an electrical current.

The end of the cable that you plug into your device will be used to mix. If you want to mix stereo, use y-splitters to get two outputs from each device and make sure your loop file contains two loops, one hard-panned right and the other left. This is good if you have a limited amount of sound sources. You can use two iPods to control four sounds.

Connect an alligator clip to the end of your mixer. Connect the other end of the clip to the tip of the audio cable connected to the speaker (or the tip of your headphone’s audio jack).

Connect the sleeve of the speaker cable to the ground of your mixing cables. In our example, these are the y-split cables.

You must also make sure all mixing cables share common ground. Do this by connecting the sleeves of each cable with a wire. It is recommended that you secure bulky cables in place with tape, otherwise they could fall and rip apart your connections. Secure the connection with electrical tape. Plug the 1/8” end of your y-splitters (or whichever cable you are using) into your device.

Start the audio on your devices. Anything with an audio output can be used, such as iPods, laptops, or in our case iPads. The level of each output should correspond to its location on the mixer, specifically the distance from the speaker connection (at the alligator clip). The graphite acts as a variable resistor. The further your probe cable is from the reference point (the speaker connection), the higher the resistance is because the amount of graphite between them is larger, and the lower the output level is.

Move the cables closer to the speaker connection to get their audio louder and vice versa.

In the first picture, all levels are about equal. In the second, the two outputs to the left (top and bottom channels) will have a lower volume than the two to the right.

Using the cables directly might be a bit bulky. For more flexibility, you can attach alligator clips to the ends of the cables and use them to mix instead.

Two stereo outputs means four level controls, which can get difficult for just one person to control. Try it out with a friend or two and see how many outputs you can control at once!

Want to see a video showing exactly how it's done rather than read through these instructions? Check out our Youtube video here where we give you a quick overview of how we put the Mixer together.