I'm trying to come up with a schematic for building a passive audio mixer for an aviation headset, but I'm having some questions about resistor values. Figuring out the general circuit is easy enough, but I'd like to bounce this off people who know a lot more than I do so I can make sure I'm doing this right.
The idea here is to combine the audio from the aircraft intercom system with the audio from a MP3 player and send it to the low impedance headset (10 ohms). I'm not that worried about sound quality because the headset itself has a small frequency range (100Hz - 5.5kHz).
Here's what I have for a schematic so far:
My question is, what should I be using for resistors here? Would 10 ohm resistors be sufficient for this? I feel like this is pretty basic stuff, but my Google Fu is failing to help me find the answer I need.