volumio@volumio:~/mpd_oled$ aplay -L
null
    Discard all samples (playback) or generate zero samples (capture)
jack
    JACK Audio Connection Kit
pulse
    PulseAudio Sound Server
default
    Playback/recording through the PulseAudio sound server
volumio
volumioPeppyalsa
reformat
mypeppy
postpeppyalsa
postPeppyalsa
volumioalsa
toLoopback
postmalsa
postalsa
volumioOutput
volumioHw
sysdefault:CARD=Headphones
    bcm2835 Headphones, bcm2835 Headphones
    Default Audio Device
dmix:CARD=Headphones,DEV=0
    bcm2835 Headphones, bcm2835 Headphones
    Direct sample mixing device
dsnoop:CARD=Headphones,DEV=0
    bcm2835 Headphones, bcm2835 Headphones
    Direct sample snooping device
hw:CARD=Headphones,DEV=0
    bcm2835 Headphones, bcm2835 Headphones
    Direct hardware device without any conversions
plughw:CARD=Headphones,DEV=0
    bcm2835 Headphones, bcm2835 Headphones
    Hardware device with all software conversions
usbstream:CARD=Headphones
    bcm2835 Headphones
    USB Stream Output
sysdefault:CARD=E30
    E30, USB Audio
    Default Audio Device
front:CARD=E30,DEV=0
    E30, USB Audio
    Front speakers
surround21:CARD=E30,DEV=0
    E30, USB Audio
    2.1 Surround output to Front and Subwoofer speakers
surround40:CARD=E30,DEV=0
    E30, USB Audio
    4.0 Surround output to Front and Rear speakers
surround41:CARD=E30,DEV=0
    E30, USB Audio
    4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=E30,DEV=0
    E30, USB Audio
    5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=E30,DEV=0
    E30, USB Audio
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=E30,DEV=0
    E30, USB Audio
    7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=E30,DEV=0
    E30, USB Audio
    IEC958 (S/PDIF) Digital Audio Output
dmix:CARD=E30,DEV=0
    E30, USB Audio
    Direct sample mixing device
dsnoop:CARD=E30,DEV=0
    E30, USB Audio
    Direct sample snooping device
hw:CARD=E30,DEV=0
    E30, USB Audio
    Direct hardware device without any conversions
plughw:CARD=E30,DEV=0
    E30, USB Audio
    Hardware device with all software conversions
usbstream:CARD=E30
    E30
    USB Stream Output
sysdefault:CARD=Dummy
    Dummy, Dummy PCM
    Default Audio Device
dmix:CARD=Dummy,DEV=0
    Dummy, Dummy PCM
    Direct sample mixing device
dsnoop:CARD=Dummy,DEV=0
    Dummy, Dummy PCM
    Direct sample snooping device
hw:CARD=Dummy,DEV=0
    Dummy, Dummy PCM
    Direct hardware device without any conversions
plughw:CARD=Dummy,DEV=0
    Dummy, Dummy PCM
    Hardware device with all software conversions
usbstream:CARD=Dummy
    Dummy
    USB Stream Output
sysdefault:CARD=Loopback
    Loopback, Loopback PCM
    Default Audio Device
front:CARD=Loopback,DEV=0
    Loopback, Loopback PCM
    Front speakers
surround21:CARD=Loopback,DEV=0
    Loopback, Loopback PCM
    2.1 Surround output to Front and Subwoofer speakers
surround40:CARD=Loopback,DEV=0
    Loopback, Loopback PCM
    4.0 Surround output to Front and Rear speakers
surround41:CARD=Loopback,DEV=0
    Loopback, Loopback PCM
    4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=Loopback,DEV=0
    Loopback, Loopback PCM
    5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=Loopback,DEV=0
    Loopback, Loopback PCM
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=Loopback,DEV=0
    Loopback, Loopback PCM
    7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
dmix:CARD=Loopback,DEV=0
    Loopback, Loopback PCM
    Direct sample mixing device
dmix:CARD=Loopback,DEV=1
    Loopback, Loopback PCM
    Direct sample mixing device
dsnoop:CARD=Loopback,DEV=0
    Loopback, Loopback PCM
    Direct sample snooping device
dsnoop:CARD=Loopback,DEV=1
    Loopback, Loopback PCM
    Direct sample snooping device
hw:CARD=Loopback,DEV=0
    Loopback, Loopback PCM
    Direct hardware device without any conversions
hw:CARD=Loopback,DEV=1
    Loopback, Loopback PCM
    Direct hardware device without any conversions
plughw:CARD=Loopback,DEV=0
    Loopback, Loopback PCM
    Hardware device with all software conversions
plughw:CARD=Loopback,DEV=1
    Loopback, Loopback PCM
    Hardware device with all software conversions
usbstream:CARD=Loopback
    Loopback
    USB Stream Output
volumio@volumio:~/mpd_oled$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: Headphones [bcm2835 Headphones], device 0: bcm2835 Headphones [bcm2835 Headphones]
  Subdevices: 8/8
  Subdevice #0: subdevice #0
  Subdevice #1: subdevice #1
  Subdevice #2: subdevice #2
  Subdevice #3: subdevice #3
  Subdevice #4: subdevice #4
  Subdevice #5: subdevice #5
  Subdevice #6: subdevice #6
  Subdevice #7: subdevice #7
card 1: E30 [E30], device 0: USB Audio [USB Audio]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 6: Dummy [Dummy], device 0: Dummy PCM [Dummy PCM]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 7: Loopback [Loopback], device 0: Loopback PCM [Loopback PCM]
  Subdevices: 2/2
  Subdevice #0: subdevice #0
  Subdevice #1: subdevice #1
card 7: Loopback [Loopback], device 1: Loopback PCM [Loopback PCM]
  Subdevices: 2/2
  Subdevice #0: subdevice #0
  Subdevice #1: subdevice #1