I just wanted to expand on the answer here https://forums.gentoo.org/viewtopic-p-8672262.html?sid=fff0843871f25abff064f3745c38aa9c#8672262:

In that post, the user is trying to run alsamixer, and gets a message

cannot open mixer: Host is down

cannot open mixer: L'hôte cible est arrêté ou en panne

they suggest to add a line

ctl.!default { type hw; card PCH; }

where PCH should be "the card description in aplay -l, also the bracketed [ ID ] in that part of /proc/asound/cards."

Here is how you do it:

$ cat /proc/asound/cards
 0 [Generic        ]: HDA-Intel - HD-Audio Generic
                      HD-Audio Generic at 0xfe088000 irq 58
 1 [Generic_1      ]: HDA-Intel - HD-Audio Generic
                      HD-Audio Generic at 0xfe080000 irq 59

$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: Generic [HD-Audio Generic], device 3: HDMI 0 [HDMI 0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: Generic [HD-Audio Generic], device 7: HDMI 1 [HDMI 1]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: Generic_1 [HD-Audio Generic], device 0: ALC295 Analog [ALC295 Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

In my case, PCH should be Generic_1 (all the contents of ~/.asoundrc):

ctl.!default { type hw; card Generic_1; }

now, alsamixer runs