Motherboard ASUS A8V-Deluxe has the following sound card:
pcm0@pci0:17:5: class=0x040100 card=0x812a1043 chip=0x30591106 rev=0x60 hdr=0x00
vendor = 'VIA Technologies Inc'
device = 'VT8233/33A/8235/8237 AC97 Enhanced Audio Controller'
class = multimedia
subclass = audio
This card is able to send audio out up to 6 speakers.
However, the FreeBSD VT8233 audio driver would only use the front speakers.
There might be a simple workaround on this one but none from the internet or patches or anything.
How-To-Repeat: By installing any 5. or 6. and then:
This does not sound amd64-specific, over to sound system maintainers