Bluetooth and hifiberry output - individually adjustable/mutable

General
1

Hi every one

I’m trying to configure mopidy/alsa in a way that I can output audio to either to a bluetooth headphone or the installed hifiberry mini amp. Optimally it would also be possible to add more bluetooth devices.

I would like to have single mixers to each output that are connected to a master mixer, which adjusts all simultaniously.

The scenario is that I have a kids music box based on moidy. As I’m not too happy to listen to kids music all the time it would be great to be able to use bluetooth headphones as well.

However, it is important to be able to use the same volume know to set the volume. Therefore the idea is to have a master mixer that adjusts all slave mixers.

What I got so far:

assound.conf:

pcm.!default {
  type hw
  card 0
}
ctl.!default {
  type hw
  card 0
}

pcm.sftvol {
          type softvol
          slave.pcm "plughw:0"
          control.name "PCM"
          control.card 0
   }

pcm.!default { 
   type plug 
   slave.pcm "sftvol" 
 }



pcm.!bluealsa {
    type plug
    slave.pcm {
        type bluealsa
        service "org.bluealsa"
        device "2C:EA:DD:C2:69:8E"
        profile "a2dp"
        #delay -20000
	control.name "Kopfhoerer"
    }
    hint {
        show on
        description "my headphones"
    }
}

pcm.!default {
  type plug
  slave.pcm "softvol"
}

pcm.softvol {
  type softvol
  slave.pcm "dmix" 
  control.name "PCM" 
  control.card 0
}

mopidy.conf:

[local]
enabled = true
media_dir = /home/pi/RPi-Jukebox-RFID/shared/audiofolders
excluded_file_extensions =
  .conf
  .jpg
  .txt
  placeholder

[file]
#enabled = true
metadata_timeout = 1

[m3u]
playlists_dir = /home/pi/RPi-Jukebox-RFID/playlists
default_encoding = UTF-8
default_extension = .m3u

[audio]
#output = alsasink
#output = audioresample ! tee name=t ! queue ! alsasink device=hifiberry t. ! queue ! audioresample ! alsasink device=btheadphone
#mixer_volume = 30
mixer=alsamixer
output= alsasink device=softvol

[alsamixer]
card=0
control= PCM
min_volume = 0
max_volume = 100
volume_scale = cubic

[mpd]
hostname = 0.0.0.0

[http]
hostname = 0.0.0.0

[iris]
country = DE
locale = de_DE

[spotify]
enabled = true
client_id = 51b54c36-b277-429e-9c83-c7b88786491b
client_secret = jzOSDdYt9A8v7fdWtQXx7ARbKAnl2dSx0K37Ky6m4SA=
#bitrate = 160
#volume_normalization = true
#private_session = false
#timeout = 10
#allow_cache = true
#allow_network = true
#allow_playlists = true
#search_album_count = 20
#search_artist_count = 10
#search_track_count = 50
#toplist_countries =

This enables the alsamixer from mopidy to adjust the volume via mopidy - however there are no bluetooth headphones and no mixer for them.

Any idea to solve this?