System wide DSP on Volumio

[ManicMunchkin]

Hello,

I'm trying to use the dsp plugin in alsa on my raspberry Pi 3 running the Volumio distro. I have created the config file under ~/.config/ladspa_dsp/config containing the following lines to check for any effects

input_channels=2
 output_channels=6
# Mapping: Left_front, Right_front, Woofer
 effects_chain=remix 0 1 0,1 0,1 0,1 . :0,1 lowpass 200 0.5 :2,3 lowpass 95 0.5

In /etc I have added the following lines to asound.conf:

 pcm.dsp {
     type plug
     slave {
        format FLOAT
        rate unchanged
    pcm {
            type ladspa
            channels 6
            path "/usr/lib/ladspa"
            playback_plugins [{
                label "ladspa_dsp"
            }]
            slave.pcm{
                type plug
                slave{
                    pcm "plughw:5,0"
                    rate unchanged
                    channels unchanged
                }
            }
        }
    }
 }

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

 ctl.!default {
    type copy
    slave.pcm "dsp"
 }

Now the problem is that I can still only select my soundcard or the sound jack as audio output in Volumio and no filtering is done to the signal to the soundcard. I am still pretty new to the linux audio system, so I don't really now where to look for problems or missed steps. I appreciate every help.

Best regards Thomas

[bmc0]

Can you choose the "default" device? If not, try adding these two lines to the pcm.dsp block:

hint.show on
hint.description "DSP'd output"

This might make the "dsp" pcm to show up in the device list.

Your ctl.!default block isn't correct, it should be

ctl.!default {
    type hw
    card 5
}

Also, make sure that your ladspa_dsp configuration is under the correct home directory (or put it in /etc/ladspa_dsp).

[ManicMunchkin]

Thanks for your quick response. After a lot of trial and error I have now got it to work when I use aplay to play a track over the dsp pcm. So I think your plugin is working correctly, now I just have to figure out how to configure the player to use the dsp module as the playback sink.

Thanks for your help.

[bmc0]

I'll close this for now since there's been no activity for a while.