Audio doesn't work very well (db 845c)

I’m trying to build a finished device and sound playback still plays a big role in using the device. I tried to output sound through the pins on the board specified in the service manual. I connected it in the same way as in the audio mezannine from db 410c. It was not possible to achieve sound. I connected a USB card, there is sound, but after a while the sound begins to crackle and distort, very similar to the fact that there is not enough buffer. I tried to output sound via hdmi, the sound plays normally, but as soon as I launch the navigator program and get directions, the sound freezes. I tried to output sound via bluetooth. Everything here seems to work without problems, but I can’t turn off the microphone on Bluetooth. That is, bluetooth has to be turned off when using a microphone. Will editing the build.prob file fix the problem?
I’m use last 1496 build aosp