HiFiBerry OS: Volume logic


For this thread, I would like to understand how the volume works because it is not clear to me. Most of volume controls rely on an external one (in the app you cast from: e.g. Spotify) 

So I wanted to check values and found

  1. 1) In the HiFiBerry OS WebUI, the audio is set at around 50%
  2. 2) when I check alsamixer my Digital is set to 14%
  3. 3) and my alsamixer Softvol is set to 100%.

So I have 3 different values:

When I use my phone to change the Spotify volume, it updates the alsamixer Digital volume.

When I use the WebUI to change the volume, it also updates the alsamixer Digital volume. But the HiFiBerry OS WebUI 50% seems to actually map with 14% in my case? When I go to around 80% in the WebUI it is only 51% in alsa:


My goal

I really need my HiFiBerries to start at 12-14% so that my neigbours would not murder me when they get bombarded with volume if it would start at Digital volumes of 30/50/100%.

Lucky for me I used Spotify most of the time and I can set the Digital volume in the /etc/vollibrespot.conf to start at 12%.


I want to fix everything now so...

  1. 1) How does the volume work in the webinterface control? Why is the % not the same? How can I make it so?

  2. 2) What alsa volume should the audio sources control in HiFiBerry OS?
    In a different thread it is mentioned that the Softvol audio is set at 100% on boot so

  3. 3) Does that mean Softvol volume control should not be used and kept at 100%?
    Because in that case I found that on snapcastmpris, the alsa volume is looking at the Softvol on the snapcastwrapper so I guess I should replace 
    mixer = self.alsa.Mixer('Softvol')
    mixer = self.alsa.Mixer('Digital')

  4. 4) So, would it not make sense on HiFiBerry OS to then NOT use snapcastmpris with the Softvol?

Thanks in advance for clarifying the audio volume logic questions I have on HiFiBerry OS.


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