Pulseaudio - onboard-audio not in sink list and poor sound quality when streaming bluetooth sound over network

  • Hi guys! I need your help with two difficulties I can't overcome installing a poor man's multi-room-bluetooth-included-pulseaudio setup:

    1. I can't find the onboard-audio-output of my raspi 2 and raspi 3 as a pulseaudio sink.

    2. Sound quality is disastrous when streaming from a smartphone via bluetooth to raspi A and then via pulseaudio rtp-stream to raspi B

    That was the very short summary. Here is what I'm trying to achieve:

    Raspi A (raspi 3) is supposed to serve as a media center: it contains my local music files and my smartphone is connected via bluetooth. There are no speakers connected, instead it should stream the audio to

    Raspi B (raspi 1 + wolfson DAC) and Raspi C (raspi 2) which should actually play the sound whenever they are turned on. All raspis are running libreelec 8.2.3.

    If you wonder why I try to stream via bluetooth and then share it over the network: It seems like the easiest way to get spotify (no premium) to work and handling podcasts is more convenient using a smartphone app than using a kodi remote (yatse in my case).

    What I did:

    Basically I tried to combine this tutorial and this one (libreelec wiki pulseaudio) trying to watch out for the hints over there (libreelec forum).

    First I set up the my smartphone-bluetooth as a pulseaudio sink on Raspi A. Then I loaded the various pulseaudio modules regarding rtp sending found in the danplanet-tutorial.

    On Raspi B I set up the wolfson-DAC as pulseaudio sink and ran the rtp-receive-comand. Before that I had installed a bluetooth-stick following the pulseaudio wiki (which worked but is not directly related to the issue).

    On Raspi C I tried to do the same.

    I set the sample-rate in the rtp-sending-comand and in pulse-daemon.conf.d of both the raspi A and B to 44100 (soxr-vhq, s161e).

    What's working:

    Playing local files from raspi A streaming to raspi B with decent sound quality.

    Streaming sound from smartphone via bluetooth directly to raspi B with decent sound quality.

    Playing local files from Raspi B

    Connecting the smartphone to raspi A, its sound is also streamed to raspi B (poor sound quality).

    What's not working:

    The sound played over smartphone - bluetooth - raspi A - pulseaudio-rtp - Raspi b is crappy and stuttering.

    Setting up Raspi C the only audio sink I could find was:

    0 auto_null module-null-sink.c s16le 2ch 48000Hz SUSPENDED

    And of course there is no sound when choosing pulseaudio in kodi.


    What I tried to solve the problem:

    a) Sound quality: As the the problem sounds similar to one of the questions below danplant's tutorial I played around randomly with sample rate, sample mode and so on. But as I'm simply following tuts without the necessary understanding of what's going on this didn't get me far. In fact I'm not even sure if all this resampling isn't just too complicated for an acceptable sound quality?

    I don't know if this is connected to the problem, but when I search for sources on Raspi A it gives me:

    1 rtp.monitor module-null-sink.c s16le 2ch 44100Hz RUNNING


    but no bluetooth device (even though as mentioned above it seems to receive and resend that bluetooth stream from my smartphone somehow).


    b) no onboard audio hardware found:

    • I tried to run this comand:

    echo "snd-bcm2835" > /storage/.config/modules-load.d/snd-bcm2835.conf

    from that other forum entry - no luck.

    • I tried to set up the sink on Raspi A - no luck.
    • This was the first thing I tried after a fresh installation of the OS.

    Thanks in advance for any help and hints!