tambien puedes probar batocera linux, kernel, xorg y controladores son muchos mas actuales que los de recalbox, quiza te funcione mejor...
salu2

@acris wooooooooooooo ok, it could not be less ... ok, enjoy those descending holidays !!!
thank you very much

I am a former user of batocera, I happened to recalbox, as it seems to provide more new and fresh ideas, there seems to be more people involved in this project.
but I have a problem that I did not have in bxxxx x64-pc.
emulators like dolphin or nds, do not run correctly or directly do not run.
mainly in my bartop with gpu "APU" integrated ati, dolphin takes a while to open to finally return to the recalbox menu.
in my ultrabook with intel i5 6200u and intel HD, it is supposed to work better since the GPU is intel and I see similar problems.
however, other emulators that use openGL, such as dreamcast, psx, or psp, work without problems.

I think it would be a good idea for pc users, an update of the "table" drivers and the linux kernel, that would solve many problems of this type and give the OS more compatibility with other systems, both new and old!
I hope to be able to play gamecube on my bartop soon, keep it up, you are doing a great job.
a greeting

resuelto...

resulta que era culpa del theme "clean retro", si pongo el theme normal si me funciona bien el volumen, no entiendo porque, pero es lo que me estaba pasando!
salu2

hola,
pues es un pc, y es la controladora integrada realteck alc662 creo....
Gracias

@fransis-j-j
en el log de emulationstation veo lo siguiente:

lvl0: VolumeControl::init() - Failed to find mixer elements!
lvl0: VolumeControl::init() - Failed to find mixer elements!
lvl0: MUSIC Error - Unable to open SDLMixer audio: ALSA: Couldn't open audio device: No such file or directory

lvl0: MUSIC Error - Unable to open SDLMixer audio: ALSA: Couldn't open audio device: No such file or directory

lvl2: playing
lvl2: Mix_PlayMusic: Audio device hasn't been opened

Buenas, desde que meti el ultimo update no me reconoce la salida de audio.
he probado a definir "auto o jack" en el "recalbox.conf", o desde la interfaz web, pero no hace nada. no hay audio...
he mirado los logs, y parece que el sistema en principio si que sigue reconociendo mis salidas de audio:
Jul 11 21:46:28 RECALBOX user.info kernel: [ 10.480934] snd_hda_intel 0000:00:01.1: Force to non-snoop mode
Jul 11 21:46:28 RECALBOX user.info kernel: [ 10.610670] snd_hda_codec_realtek hdaudioC1D0: autoconfig for ALC662 rev1: line_outs=1 (0x14/0x0/0x0/0x0/0x0) type:line
Jul 11 21:46:28 RECALBOX user.info kernel: [ 10.610673] snd_hda_codec_realtek hdaudioC1D0: speaker_outs=0 (0x0/0x0/0x0/0x0/0x0)
Jul 11 21:46:28 RECALBOX user.info kernel: [ 10.610674] snd_hda_codec_realtek hdaudioC1D0: hp_outs=1 (0x1b/0x0/0x0/0x0/0x0)
Jul 11 21:46:28 RECALBOX user.info kernel: [ 10.610675] snd_hda_codec_realtek hdaudioC1D0: mono: mono_out=0x0
Jul 11 21:46:28 RECALBOX user.info kernel: [ 10.610676] snd_hda_codec_realtek hdaudioC1D0: inputs:
Jul 11 21:46:28 RECALBOX user.info kernel: [ 10.610677] snd_hda_codec_realtek hdaudioC1D0: Front Mic=0x19
Jul 11 21:46:28 RECALBOX user.info kernel: [ 10.610678] snd_hda_codec_realtek hdaudioC1D0: Rear Mic=0x18
Jul 11 21:46:28 RECALBOX user.info kernel: [ 10.610683] snd_hda_codec_realtek hdaudioC1D0: Line=0x1a
Jul 11 21:46:28 RECALBOX user.info kernel: [ 10.762694] input: HDA ATI HDMI HDMI/DP,pcm=3 as /devices/pci0000:00/0000:00:01.1/sound/card0/input11
Jul 11 21:46:28 RECALBOX user.info kernel: [ 10.765417] input: HD-Audio Generic Rear Mic as /devices/pci0000:00/0000:00:14.2/sound/card1/input8
Jul 11 21:46:28 RECALBOX user.info kernel: [ 10.765531] input: HD-Audio Generic Line as /devices/pci0000:00/0000:00:14.2/sound/card1/input9
Jul 11 21:46:28 RECALBOX user.info kernel: [ 10.765625] input: HD-Audio Generic Line Out as /devices/pci0000:00/0000:00:14.2/sound/card1/input10

tambien he probado desde terminal "alsamixer", todos los volumenes estan al maximo, y me detecta correctamente mi controladora de audio por jack, realtek alc. osea parece un problema de los scrips, porque el sistema sigue reconociendo perfectamente el hardware, como lo puedo solucionar?
Gracias