The HD-3 has an 1/8" (3.5mm) "MIX IN" input on the side panel which lets you connect an external audio player. This is convenient for when you want to play the HD-3 while listening to music at the same time.
To do this, all you need is the correct cable to connect your audio device to the HD-3.
- If your audio player has an 1/8" output connection, then you'll need a stereo 1/8" cable. This type of cable can be used to connect to your cell phone (iPhone etc.) the headphones output on your computer.
- If your audio player has 1/4" connection for its output, you'll need a stereo 1/4" -1/8" cable.
Other cables are available as well, including RCA - 1/8" stereo.
Once you have chosen the correct cable, simply connect the appropriate end to your audio device, and the opposite (1/8") end to the MIX IN jack on the left side panel of HD-3. Then, turn up the volume and press play on your audio player. Make sure you have headphones connected to your HD-3 and its volume is up as well. If you have the Main outs on the HD-3 connected to an external mixer or amp, make sure the mixer / amp's volume is up.
Note of caution: Never connect the "powered" speaker output from an external mixer or source to the MIX IN jack. Doing so can damage the HD-3.