@bai4Iej2need yes it would be in addition. Your settings defines the CARD "variable" and it thus applies separately and together.

Though, as @igorzwx noted, the default setup might already have dsnoop and dmix.

That's a great .asoundrc example. Though you could have omitted "primary_system" tree which most likely will confuse the casual reader

I suggest the OP should only consider the part following # Configuration for PCH.

You, the reader, may however note the similarities between the "default" tree and the "primary_system" tree (which targets the USB sound card), and pay attention to the differences in their sample rates and bit sizes (48k, 16 bits versus 192k, 32 bits). In both cases rate conversions are handled by fftrate which @igorzwx introduced us to last year.

See e.g, https://dev1galaxy.org/viewtopic.php?id=7142 or search fftrate on the forum. We are still longing for a debian packaging of this.

For some firefox version I had to introduce a "dsnoop" pcm on the capture side, so that it could handle multiple concurrent accesses to the microphone. It appeared to be that firefox opened the microphone device before forking and thereby ended up in access contention with itself; the "dsnoop" pcm allows the microphone to be shared.

It resulted in a few pcm declarations in ~/.asoundrc:

pcm.!default {
    type plug
    slave {
        pcm splitter
        rate 48000 ; channels 2
    }
}
pcm.splitter {
    type asym
    playback.pcm plughw
    capture.pcm mic
}

# The "mic" PCM adds "dsnoop" to source opening, which allows a single
# source be used by many "consuming processes". This is required by
# firefox, which otherwise locks out itself from using the microphone.
pcm.mic {
    type dsnoop
    ipc_key 5
    ipc_key_add_uid false
    slave {
        pcm "hw:0,0"
        period_size 2048 ; buffer_size 16384
        periods 0 ; period_time 0
        format S16_LE ; rate 48000 ; channels 2
    }
}

Something like that; it was a while ago and I'm not totally sure about it.

Why use Microsoft's server for FOSS ?
Why not git.devuan.org ?
Or codeberg.org ?

The four labels main, contrib, non-free and non-free-firmware are known as sections;

The four labels excalibur, excalibur-updates, excalibur-secority and excalibur-proposed-updates are known as codenames;

The URL http://deb.devuan.org/merged is known as the base.

The prefix label deb indicates that the line is for binary packages, and the prefix label deb-src indicates that the line is for source packages.

Each sources.list line includes (in order) a prefix label, the base, a codename, and one or more sections. You can have it as 4 lines with a single section on each, or as a single line with all four sections.

I suggested you have one deb line for each codename, with all 4 sections, and one deb-src line for each codename, with all 4 sections.

The order is not important, but duplicates might be a bother. I.e., you should remove the top two, because the are duplicates for excalibur/main and excalibur/non-free-firmware.

In addition, you should probably add sources.list lines for excalibur-updates and excalibur-proposed-updates ... also using sections main, contrib, non-free and non-free-firmwares. With that you would be more "future ready".

Have you verified uuid? it's unusual for me to see ":" rather than "-" in uuid, though it may well be an mdadm thing(?)

ls -l /dev/disk/by-uuid

In any case I'll set up a VM trial to see if I can replicate your problem.

It appears your /etc/apt/sources.list.d/devuan.sources have blank lines that are not empty, but each contains a single space character. Therefore that whole file becomes treated as a single block of key: value pairs, where the last one for each key overrides all other.

I don't know which which editor you use to accomplish that single-space-character blank lines, but if you run the following command it will be happier:

sed 's/^\s*$//' -i /etc/apt/sources.list.d/devuan.sources

You can verify that the file is slightly smaller after the command, and if you first copy the file to /tmp/OLD you can compare them with diff or meld to see what I talked about already some posts ago.

Nowadays we also have the pipewire-alsa package that does the same as pulseaudio-alsa but directing to pipewire instead.

Indeed, it seems prepared for random asynchronous bootup when one has configured it so. Though it seems the default setup case is the invocation at line 90, where the hook script is used explicitly.

That blank line between the stanzas, does that contain any spaces or tab?

You could use https://transfer.rrq.au if you like