Hi, I want to record the headphone output from my digital piano on my phone, so am treating it like a mic-input to the phone. I've tried two different TRS-TRRS microphone adapters but the phone just says 'earphones connected' and doesn't detect the mic at all. The only thing I've found relates to differing TRRS standards, but don't know if that could be the issue. The adapters say they're CTIA standard (and the cable and headphone output are fine). I can listen through headphones plugged into the phone so it's not an obvious issue with the jack.