ALSA - Play Music on simultaneouse 2 sound cards
 

Dear Forum,
I am looking for suggestions for how can I play audio (Mythtv - Play Music) simultaneously on two sound cards using ALSA drivers.
I have two cards working well. One card is an onboard Intel cards, and the other card is a USB Audio card. Both cards are working well. I use the onboard Intel to output SPDIF to an amplified. The second USB card is bound to MPD service and it outputs an analog signal to a second amplified.

I'd like to have the following configuration:

Play to the default card with 5.1 passthrough, while the second card, connected to a second amplifier, plays an analog signal to the same audio played by Mythtv Play Music.

In other words, I need to mix somehow and play the same audio on both cards.
Here is the list of cards:
root@mythtv:~# aplay -L
null
Discard all samples (playback) or generate zero samples (capture)
default:CARD=Intel
HDA Intel, ALC660-VD Analog
Default Audio Device
front:CARD=Intel,DEV=0
HDA Intel, ALC660-VD Analog
Front speakers
surround40:CARD=Intel,DEV=0
HDA Intel, ALC660-VD Analog
4.0 Surround output to Front and Rear speakers
surround41:CARD=Intel,DEV=0
HDA Intel, ALC660-VD Analog
4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=Intel,DEV=0
HDA Intel, ALC660-VD Analog
5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=Intel,DEV=0
HDA Intel, ALC660-VD Analog
5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=Intel,DEV=0
HDA Intel, ALC660-VD Analog
7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=Intel,DEV=0
HDA Intel, ALC660-VD Digital
IEC958 (S/PDIF) Digital Audio Output
default:CARD=default
USB Sound Device , USB Audio
Default Audio Device
front:CARD=default,DEV=0
USB Sound Device , USB Audio
Front speakers
surround40:CARD=default,DEV=0
USB Sound Device , USB Audio
4.0 Surround output to Front and Rear speakers
surround41:CARD=default,DEV=0
USB Sound Device , USB Audio
4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=default,DEV=0
USB Sound Device , USB Audio
5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=default,DEV=0
USB Sound Device , USB Audio
5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=default,DEV=0
USB Sound Device , USB Audio
7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=default,DEV=0
USB Sound Device , USB Audio
IEC958 (S/PDIF) Digital Audio Output
Any ideas?

Thanks,

Ale99

i did not think that ALSA could do this .
have you looked at pulse audio

ALSA's wiki site has examples how to do this. The following has the example.

http://alsa.opensrc.org/index.php/Asoundrc