I think it's 4.0 ... because I installed a while ago and I do not remember...
aplay -L:
null
Discard all samples (playback) or generate zero samples (capture)
default:CARD=ICE1724
ICEnsemble ICE1724, ICE1724
Default Audio Device
front:CARD=ICE1724,DEV=0
ICEnsemble ICE1724, ICE1724
Front speakers
surround40:CARD=ICE1724,DEV=0
ICEnsemble ICE1724, ICE1724
4.0 Surround output to Front and Rear speakers
surround41:CARD=ICE1724,DEV=0
ICEnsemble ICE1724, ICE1724
4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=ICE1724,DEV=0
ICEnsemble ICE1724, ICE1724
5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=ICE1724,DEV=0
ICEnsemble ICE1724, ICE1724
5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=ICE1724,DEV=0
ICEnsemble ICE1724, ICE1724
7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=ICE1724,DEV=0
ICEnsemble ICE1724, ICE1724
IEC958 (S/PDIF) Digital Audio Output
aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: ICE1724 [ICEnsemble ICE1724], device 0: ICE1724 [ICE1724]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 0: ICE1724 [ICEnsemble ICE1724], device 1: ICE1724 IEC958 [ICE1724 IEC958]
Subdevices: 1/1
Subdevice #0: subdevice #0
and now what?