1

Yet another Amp2 - Mono Output thread

Simon

September 23, 2018 14:53

None

Follow

I know there are several posts on subject of getting a mono output for dotted about this forum but none seem to work for Amp2 or just dont make sense. 

I have built a wireless speaker out of an old Centre Speaker from a 5.1 system. I use Roon as well as Spotify and Qobuz via Raspotify and mpd/upmpdclli. all running via Dietpi os which is based on Stretch Raspbian

In Roon I have configured the output to be mono by using its inbuilt DSP which is great. But this won't work for the rest of my input sources. So is there a way to configure the output of the dac or the amp end of it to output a true mono signal not just the left or the right? I don't want to bridge the speaker outputs as this might cause damage to the amp as I believe its not in its designed to do this.

Anyone else managed this on the Amp2

• Facebook
• Twitter
• LinkedIn

7 comments

• 0
  
  Simon September 24, 2018 21:04

  Well I found a config that works. Happy now.

  change /etc/asound.conf to below

  pcm.card0 {
  type hw
  card 0
  }

  ctl.card0 {
  type hw
  card 0
  }

  pcm.monocard {
  slave.pcm card0
  slave.channels 2
  type route
  ttable {
  # Copy both input channels to output channel 0 (Left).
  0.0 0.5
  1.0 0.5
  # Send nothing to output channel 1 (Right).
  0.1 0
  1.1 0
  }
  }

  ctl.monocard {
  type hw
  card 0
  }

  pcm.!default monocard
  ctl.!default monocard

• 0
  
  HiFiBerry team September 25, 2018 06:59

  Thanks for posting the configuration. This might also help other users.

• 1
  
  Simon December 23, 2018 20:52

  Thats what it's supposed to do, mono mixdown out of left speaker, it's not a dual mono cfg. You can alter it for that. Works fine for me in deitpi.

• 0
  
  De Adi December 24, 2018 10:34

  Hi Simon. Thanks and sorry for my blackout. - How would you alter those params to a dual mono config? or where can i look it up?

  # Send nothing to output channel 1 (Right).
  0.1 0
  1.1 0

• 0
  
  Simon December 24, 2018 13:22

  Not exactly sure , but I would imagine you need to repeat the copy input channels to the right channel as well so
  0.1 0.5
  1.1 0.5

  And remove the last section .

  But I am no expert I googled and tried to find one that worked so can't take any responsibility for what this might do.

• 0
  
  bendix February 10, 2019 20:42

  I cannot seem to get this working. If I overwrite my asound.conf with the provided info I get no sound. Tried under raspbian and under Max2Play, same thing.

  Anyone that can help with more detailed how-to for this? 

• 0
  
  bendix February 10, 2019 20:46

  Also, everytime I try, I cannot seem to undo and get it working again. The sound is just gone completely until I reformat SD and reinstall everything. Quite annoying :(