# http://alsa.opensupmix_20to21rc.org/SurroundSound
# http://alsa.opensrc.org/Low-pass_filter_for_subwoofer_channel_%28HOWTO%29
# analyseplugin cmt
# http://plugin.org.uk/ladspa-swh/docs/ladspa-swh.html
# LADSPA-Filters by Richard Taylor (http://faculty.tru.ca/rtaylor/rt-plugins/index.html)
 
pcm.upmixplug {
    type plug
    slave.pcm "upmix_20" #target for audiostream
    slave.channels 2
    slave.format S32_LE
    hint {
        show on
        description "UpMix" #name for phonon-device
    }
}
 
pcm.upmix_20{
#    type plug
#    slave.pcm "upmixfilters"
#    slave.channels 3
    type route
    slave.pcm {
        type lfloat
        slave.pcm "upmixfilters"
        slave.format FLOAT_LE
    }
    slave.channels 3
    slave.format S32_LE
    ttable {
    #mixing: add <channel> to <channel> multiplied by <factor>
    #<channel>.<channel> <factor>
        0.0  1      # left channel
        1.1  1      # right channel
        0.2  0.5    # mix left and right ...
        1.2  0.5    # ... channel for subwoofer
    }
}
 
    pcm.upmixfilters {
        #input: channel 0: Left, channel 1: right, channel2: left/2+right/2
     
        type ladspa
        slave.pcm upmix_to21
        path "/usr/lib/ladspa"
        channels 3
        plugins {
          0 {
             id 1098  # Identity (Audio) (1098/identity_audio)
             policy duplicate
             input.bindings.0 "Input";
             output.bindings.0 "Output";
          }
     
          1 {
             id 9021  #Linkwitz-Riley 4th-order high-pass by Richard Taylor
             policy none
             input.bindings.0 "Input";
             output.bindings.0 "Output";
             input {
                controls [ 80 ]
             }
          }
     
          2 {
             id 9021 #Linkwitz-Riley 4th-order high-pass by Richard Taylor
             policy none
             input.bindings.1 "Input";
             output.bindings.1 "Output";
             input {
                controls [ 80 ]
             }
          }
     
          3 {
             id 9020  #Linkwitz-Riley 4th-order low-pass by Richard Taylor
             policy none
             input.bindings.2 "Input";
             output.bindings.2 "Output";
             input {
                controls [ 80 ]
             }
          }
          #output: channel 0: left highpass-filtered (80Hz), channel 2: right highpass-filtered (80Hz), channel2: left/2+right/2 lowpass-filtered (80Hz) for subwoofer
       }
    }
 
pcm.upmix_to21 { #uncomment lines for 5.1
    type plug   slave.pcm "surround51:CARD=D2X"
    slave.channels 6
    ttable {
      0.0     1       # front left
      1.1     1       # front right
      #0.2    1       # rear left
      #1.3    1       # rear right
 
      # Front left/right to center.
      #0.4     0.5
      #1.4     0.5
 
      # Subwoofer, more powerful to compensate for bass-removal from other speakers.
      # Would normally be 1.
      2.5     2
    }
}