HOWTO : Send mono to both speaker


I've been reading a lot of posts from users who can't have mono output to both speaker.

There is of post on hifiberry.com but I had to modify the conf file to make it work.

First, identify your card output with aplay -l

My card was identified as "card 2":

card 2: sndrpihifiberry [snd_rpi_hifiberry_dacplus], device 0: HiFiBerry DAC+ HiFi pcm512x-hifi-0 [HiFiBerry DAC+ HiFi pcm512x-hifi-0]

Then, write the following code to a file named /etc/asound.conf, and replace card 2 with the card you need.
If, like me, you are using squeezelite to play sound, you can now use the default alsa device (-o default when you launch squeezelite).

pcm.card2 {
type hw
card 2

ctl.card2 {
type hw
card 2

pcm.monocard {
slave.pcm card2
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 0.5
1.1 0.5

ctl.monocard {
type hw
card 2

pcm.!default monocard
ctl.!default monocard



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