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Wolfson and MPD  working

superpat

Hi,

 

I installed MPD onto the provided Wolfson Audio distribution, running it headless,  console via ssh.

 

I copied the provided demo flac files to the mpd music directory.

 

I ran alsamixer and wound up the digital i/p's and outputs.

 

controlling  MPD with the GMPC client on my LInux desktop

 

96Kbps flacs are playing  superbly, output  lineout  and into my desktop audio amp and speakers,

 

Next I will set mpd to get music from my NAS using nfs, which will be interesting, as this tends load the Pi system and  cause problems with the Pi and usb dacs!

 

cheers

 

 

P

  • in reply to Former Member

    OK, so I will send it back...

     

    20 hours wasted because of a defect hardware... image

     

    anyway: THANK YOU for your HELP & PATIENCE!!!

  • Hello,

    I using Raspian + MPD + Wolfson audio card over NFS. I plugged the Lineout output on Hifi amplifier and it's working well except one thing : the volume control.

    I can't control volume with any Music Player clients.

    I think the mixer is not correctly configured but I don't know how I can configure it. Do you have any suggestions (tests or settings ) ?

     

    Thank you in advance !

  • in reply to Former Member

    Hi Alexis,

    I had the same problem. But I think I finally found the right setting to use the hardware mixer of the WM5102 with mpd. This is the important part of the mpd.conf:

    audio_output {
    type          "alsa"
    name          "Wolfson"
    device        "hw:0"
    mixer_type    "hardware"
    mixer_control "HPOUT2 Digital"
}

    But be careful I'm not sure if this is fully correct and reduce the volume of your amp. Just in case ;-)

     

    If this matters: I use alsa-utils 1.0.28-1 and mpd 0.18.12-1

  • in reply to Former Member

    Hello,

    Thank you twoflower.

    I can now control the volume through my favourite mpd client. However, It's difficult to adjust the volume without saturating my amplifier, because it seems that the volume scale is not linear but something almost exponential.

    Do you know if I can limit the upper volume value to avoid this behaviour ?

  • I noticed that today too. The evening I found this configuration I was not trying this out in the sake of my neighbors sleep. So far I haven't found a fully working solution. Reducing the input levels of the mixer seems to help little:

    > amixer -Dhw:0 cset name='HPOUT2L Input 1 Volume' 10
> amixer -Dhw:0 cset name='HPOUT2R Input 1 Volume' 10

    But the distortion stays there. I wish I would have a scope here to understand a little better what happens. And/Or some more time to read the 500+ pages datasheet of the WM5102.

     

    UPDATE: OK, I think I understand what's going on. According to the WM5102 datasheet all values above 0x80 (128) will amplify the input signal. That's what we want to avoid. This behavior seems to be true for most if not all volume knobs in the device. This might be useful in case you have low input signals. But in normal cases this will cause distortions. A solution might be to tell alsa (the mixer used by mpd) that the maximum value is not 0xBF (191) but 0x80 or a bit lower to avoid clipping. But so far I was not able to find the place to override the default. If I understand this right, alsa 'asks' the device about which knobs and values are valid. So there's no existing config file to tweak. But I'm sure there's a way to override stuff. One candidate is to create a alsactl_init but this seems to be not a 5 minute task to understand.