Asound: equalizer AND mono downmix?

[Neidhart]

Hi all,

I’m using DietPi as a snapclient on a Pi Zero W with a Hifiberry MiniAMP or AMP2.
Output works great, however I can’t implement equalizer and mono downmix at the same time.

I have two working asound.confs: one for equalizer and one for mono downmix on left channel.

Working equalizer as generated by dietpi-config:

pcm.!default {
        type plug
        slave.pcm {
                type equal
                slave.pcm {
                        type plug
                        slave.pcm {
                                type hw
                                card 0
                                device 0
                        }
                }
                controls "/var/lib/dietpi/dietpi-config/.alsaequal.bin"
        }
}

ctl.eq {
        type equal
        controls "/var/lib/dietpi/dietpi-config/.alsaequal.bin"
}

ctl.!default {
        type hw
        card 0
}

and a working Mono downmix as a reuse from a Picoreplayer installation:

pcm.!default {
        type route
        slave.pcm "hw:0,0"
        ttable {
                0.1 1
                0.0 1
                1.0 1
                1.1 1
        }
}

Both configs work but I can not combine them into a single solution for equalizer and mono downmix. Where do I have to put the ttable information?

[Jappe]

To combine the equalizer and mono downmix in a single asound.conf, you need to nest the mono downmix configuration within the equalizer configuration. The ttable (transformation table) for the mono downmix should be placed inside the pcm.!default block of the equalizer configuration.

(I took this info from an AI , pls make a backup from the old configs before you change anything)

pcm.!default {
    type plug
    slave.pcm {
        type equal
        slave.pcm {
            type plug
            slave.pcm {
                type route
                slave.pcm {
                    type hw
                    card  0
                    device  0
                }
                ttable {
                    0.1  1
                    0.0  1
                    1.0  1
                    1.1  1
                }
            }
        }
        controls "/var/lib/dietpi/dietpi-config/.alsaequal.bin"
    }
}

ctl.eq {
    type equal
    controls "/var/lib/dietpi/dietpi-config/.alsaequal.bin"
}

ctl.!default {
    type hw
    card  0
}

[Neidhart]

Hi, thanks for your input.

I tested your config with a stereo test mp3 file, but only got the audio from the left channel (where I have a speaker connected).

[Jappe]

To be honest idk what now the issue is. You have output and ttable looks okay, it should route left source channel to both ( 0.1 1 and 0.0 1) and the same for the other input channel.
Maybe somebody else has an idea.