Since ALSA mixer commands are not accessible from Linux Raspbian Buster in RPi4b, I saw that they are replaced by PulseAudio, a network-capable sound server program distributed via the freedesktop.org project.

In broad terms I understand ALSA is a kernel subsystem that provides the sound hardware driver, and PulseAudio is the interface engine between Applications and ALSA. In a typical installation scenario under Linux, the user configures ALSA to use a virtual device provided by PulseAudio. Thus, applications using ALSA will output sound to PulseAudio, which then uses ALSA itself to access the real sound card. PulseAudio also provides its own native interface to applications that want to support PulseAudio directly, as well as a legacy interface for ESD applications, making it suitable as a drop-in replacement for ESD. I cannot find ALSA mixer commands in raspbian buster, that is because they are not there, so the sound uses pulseaudio directly ? or ALSA is running behind pulse audio?

So, in this context.... Audio Injector Stereo Sound Card... with Raspbian buster on RPi4b.. will still work with pulseaudio directly or only with ALSA mixer behind?, I need to reinstall ALSA mixer to recognize and access the sound card parameters?, or I can access and control sound card with ALSA behind pulse audio in some form?. Is it possible to manage sound cards via pulseaudio directly?. Has anyone tested this issue? Do I need to go back to RPI3b+ and Raspbian Jesse to use ALSA mixer with this sound card?

A lot of questions.. excuse me....

Please, if anyone could help me..., it will be really important for a music project with my son at school now, so it will affect the decision to buy 5 to 10 sound stereo cards from audio injector. I am from Argentina, sorry for my english since it is not my native language.

Thank you very much in advance to everyone.

Esteban.