I'm looking for a way to wire the stereo output of a device into its own mono microphone input. This will be soldered as a 4 pin 3.5mm TRRS audio jack.
I need to record the output of my smartphone on the smartphone itself (without software modification.) I have screen recording apps available, but they take audio from the microphone.
I tried two circuits:
- Android official Audio Loopback Dongle (stackoverflow question about this circuit) - this works but distorts human speech. Perhaps incorrect resistor/capacitor values?
- Headphone Output/STEREO MIX To MIC Input For Recording, but wired input and output together, ground left not connected. Android doesn't detect this as an mic and uses internal microphone.