Android Question How to get the sound of music playing on phone

[poya10]

Hi, I want to get the sound of music playing on my phone, then with the xFFT library, extract the sound level at 50 Hz and then show the level on a label. I was able to do it with a microphone before, but the microphone does not work well for me. Basically, I want to extract the bass sound level and show that on a label.