Set secondary sound card as default

Hi guys, I have a problem and the cause is lack of knowledge.

I’m usign Manjaro KDE, but I would love to use a WM and after some research I choose Qtile. To be sure to migrate with a backup I created a second user only for Qtile environment. I think the main point here is not the window manager but my lack of knowledge in arch. As said I have two users, a kde user (main installation, for backup session purpose) and a Qtile user for daily use and experiment. This mean separate configuration files for homes folder and, if I will be confortably with the WM, I will uninstall KDE and delete the first user. My issue is that Qtile don’t have sound and I don’t know how to solve the problem. I had tried some solution found via google but nothing really helped.

Of what I understood, the audio is working fine on “motherboard sound chip” but is not what I wnat to use. I have a second card that is working fine on KDE, a Sound Blaster Z. Pulse audio daemon is running it seems, and with alsamixer I can see the device and change volumes. But “I think” that the system in Qtile outputs the sound on the default “motherboard chip”. On KDE I had set the sound blaster as main device but on Qtile I don’t really know how to do it.

As I said, I want to change the default sound device only for the Qtile user and not for the whole system, because I don’t want to screw up KDE in any way. Do you have any advice?

How to increase your chances of solving your issue:

Please provide Information:

Is PulseAudio configured for both users to share one daemon?
PulseAudio/Examples/Allowing multiple users to share a PulseAudio daemon | Archwiki

(example in Archwiki does not mention commands systemctl --user restart pulsaudio to restart PulseAudio or pactl exit)

If the Qtile user is configured as primary user and KDE as secondary user by configuration files
~/.config/pulse/ the SoundBlaster card can be set as default-sink for audio output can be set in the qtile user configuration

Find the sink Name recognised in PulseAudio with this command

pactl list sinks

and add the name to end of configuration file: set-default-sink (Name)

Use this command to check if default-sink is set correctly

pacmd dump | grep default-sink