Checking out if an ALSA driver for a sound card is installed

[Adam Mazurkiewicz]

My Sound Blaster PCI card is not working, so I have watched things
around ALSA drivers.

In fact I cannot state if ALSA is installed:

The   M-x guix-default-services for  %desktop-services is this:
(...)
  agetty                    gnu/services/base.scm:1104:2
Provide console login using the `agetty' program.
  alsa                      gnu/services/sound.scm:93:2
Configure low-level Linux sound support, ALSA.
  avahi                     gnu/services/avahi.scm:145:4        Run
`avahi-daemon', a host and service discovery daemon that implements
the multicast DNS (mDNS) and DNS service discovery (DNS-SD) protocols.
Additionally, extend the C library's name service switch (NSS) with
support for `.local' host name resolution.
(...)

So ALSA is present in services, but aplay command doesn't work:

bash-4.4# aplay -l
bash: aplay: command not found
bash-4.4# find / -name aplay
/gnu/store/04g77pl6i6b8adj7pr1kbsz0qjar021z-alsa-utils-1.1.8/bin/aplay
find: ‘/run/user/1000/gvfs’: Permission denied
bash-4.4#

The card is visible here:
bash-4.4# lspci -nnk
(...)
01:00.0 Multimedia audio controller [0401]: Creative Labs
EMU10k2/CA0100/CA0102/CA10200 [Sound Blaster Audigy Series]
[1102:0004] (rev 04)
    Subsystem: Creative Labs SB0240 Audigy 2 Platinum 6.1 [1102:1002]
01:00.1 Input device controller [0980]: Creative Labs SB Audigy Game
Port [1102:7003] (rev 04)
    Subsystem: Creative Labs SB Audigy2 MIDI/Game Port [1102:0060]
    Kernel driver in use: Emu10k1_gameport
    Kernel modules: emu10k1_gp
01:00.2
(...)
How to check out if ALSA is installed or how to install it?