MPD and ALSA settings on cubox-i

I have had some trouble with some songs playing on my cubox-i via the SPDIF-Toslink connection. I heard crackling noises on those songs. First I thought, that those were due to some mistake done during ripping those from my CDs. But I tested those songs on some other devices and recognized, that it is most probably due to high frequencies or something similar.

Therefor I digged into the concrete settings of ALSA and MPD to fiddle around with Frequency- and Volume-Settings. In the end it turned out, that the solution is rather easy and I just had to reduce the volume of the cubox-i SPDIF out to 98%. Now all crackling noises are gone and I can enjoy the music via my home stereo system.

Here are the settings of ALSA (/etc/asound.conf):


pcm.imxspdif {
type hw
card imxspdif
}

pcm.imxhdmisoc {
type hw
card imxhdmisoc
}

ctl.imxspdif {
type hw
card imxspdif
}

ctl.imxhdmisoc {
type hw
card imxhdmisoc
}

The above settings are just setting the devices in the Cubox-I to be used by alsa. The „imxspdif“ is important, because this one is used by the following MPD-setting:


audio_output {
type "alsa"
name "imxspdif"
mixer_type "software"
}

Unfortunately I could not use „alsactl store“ to store my alsamixer settings, therefor I have set the mixer_type of MPD to software, which allows to call the


mpd volume -2

command inside of my mediaplayer-startup script. This command sets the used volume to 98%. Now everything is working fine, on every boot, like wanted 😉