5 - Les serveurs son : JACK, PipeWire, PulseAudio et autres...

phil@UbuntuStudio:~$ cat /proc/asound/cards
 0 [io2            ]: USB-Audio - io|2
                      Alesis io|2 at usb-0000:00:1d.0-1, full speed
 1 [ICH6           ]: ICH4 - Intel ICH6
                      Intel ICH6 with AD1981B at irq 21

# autoloader aliases
install sound-slot-1 /sbin/modprobe snd-card-0
install sound-slot-0 /sbin/modprobe snd-card-1
install sound-slot-2 /sbin/modprobe snd-card-2
install sound-slot-3 /sbin/modprobe snd-card-3
install sound-slot-4 /sbin/modprobe snd-card-4
install sound-slot-5 /sbin/modprobe snd-card-5
install sound-slot-6 /sbin/modprobe snd-card-6
install sound-slot-7 /sbin/modprobe snd-card-7

# Cause optional modules to be loaded above generic modules
install snd /sbin/modprobe --ignore-install snd $CMDLINE_OPTS && { /sbin/modprobe --quiet --use-blacklist snd-ioctl32 ; /sbin/modprobe --quiet --use-blacklist snd-seq ; }
#
# Workaround at bug #499695 (reverted in Ubuntu see LP #319505)
install snd-pcm /sbin/modprobe --ignore-install snd-pcm $CMDLINE_OPTS && { /sbin/modprobe --quiet --use-blacklist snd-pcm-oss ; : ; }
install snd-mixer /sbin/modprobe --ignore-install snd-mixer $CMDLINE_OPTS && { /sbin/modprobe --quiet --use-blacklist snd-mixer-oss ; : ; }
install snd-seq /sbin/modprobe --ignore-install snd-seq $CMDLINE_OPTS && { /sbin/modprobe --quiet --use-blacklist snd-seq-midi ; /sbin/modprobe --quiet --use-blacklist snd-seq-oss ; : ; }
#
install snd-rawmidi /sbin/modprobe --ignore-install snd-rawmidi $CMDLINE_OPTS && { /sbin/modprobe --quiet --use-blacklist snd-seq-midi ; : ; }
# Cause optional modules to be loaded above sound card driver modules
install snd-emu10k1 /sbin/modprobe --ignore-install snd-emu10k1 $CMDLINE_OPTS && { /sbin/modprobe --quiet --use-blacklist snd-emu10k1-synth ; }
install snd-via82xx /sbin/modprobe --ignore-install snd-via82xx $CMDLINE_OPTS && { /sbin/modprobe --quiet --use-blacklist snd-seq ; }

# Load saa7134-alsa instead of saa7134 (which gets dragged in by it anyway)
install saa7134 /sbin/modprobe --ignore-install saa7134 $CMDLINE_OPTS && { /sbin/modprobe --quiet --use-blacklist saa7134-alsa ; : ; }
# Prevent abnormal drivers from grabbing index 0
#options bt87x index=-2
#options cx88_alsa index=-2
#options saa7134-alsa index=-2
#options snd-atiixp-modem index=-2
#options snd-intel8x0m index=-2
#options snd-via82xx-modem index=-2
#options snd-usb-audio index=-2
#options snd-usb-caiaq index=-2
#options snd-usb-ua101 index=-2
#options snd-usb-us122l index=-2
#options snd-usb-usx2y index=-2
# Ubuntu #62691, enable MPU for snd-cmipci
#options snd-cmipci mpu_port=0x330 fm_port=0x388
# Keep snd-pcsp from being loaded as first soundcard
#options snd-pcsp index=-2
# Keep snd-usb-audio from beeing loaded as first soundcard
## Configuration spécifique pour passer par défaut l'Alesis
options snd-usb-audio index=0
options snd-intel8x0 index=1

[...]
; default-sink =
; default-source =
; default-server =
__
autospawn = no__
; daemon-binary = /usr/bin/pulseaudio
; extra-arguments = --log-target=syslog

; cookie-file =

; enable-shm = yes
; shm-size-bytes = 0 # setting this 0 will use the system-default, usually 64 MiB
[...]

pcm.io2 {
       type hw
       card io2
}
ctl.io2 {
       type hw
       card io2
}
pcm.!default {
       type plug
       slave {
              pcm io2
              format S24_3LE
       }
}

JACK server starting in realtime mode with priority 89
audio_reservation_init
Acquire audio card Audio0
creating alsa driver ... hw:0|hw:0|16|2|48000|0|0|nomon|swmeter|-|32bit
Using ALSA driver USB-Audio running on card 0 - Alesis io|2 at usb-0000:00:1d.0-1, full speed
configuring for 48000Hz, period = 16 frames (0.3 ms), buffer = 2 periods
ALSA: final selected sample format for capture: 24bit little-endian
ALSA: cannot set period size to 16 frames for capture
ALSA: cannot configure capture channel
Cannot initialize driver
JackServer::Open() failed with -1
Failed to start server

15:39:24.496 Impossible de connecter le serveur JACK comme client. - L'opération a échoué. - Incapable de se connecter au serveur. Veuillez consulter la fenêtre des messages pour plus d'informations.
Cannot connect to server socket err = Aucun fichier ou dossier de ce type
Cannot connect to server socket
jack server is not running or cannot be started