installed and enabled oss
pkg install oss; sysrc oss_enable="YES"
>>> does it also work without ?

-----
dmesg | grep pcm | sort | uniq

pcm0: <NVIDIA (0x0060) (HDMI/DP 8ch)> at nid 4 on hdaa0
pcm1: <NVIDIA (0x0060) (HDMI/DP 8ch)> at nid 5 on hdaa0
pcm2: <NVIDIA (0x0060) (HDMI/DP 8ch)> at nid 7 on hdaa0
pcm3: <Realtek ALC671 (Analog)> at nid 23 and 24,26 on hdaa1
pcm4: <Realtek ALC671 (Front Analog)> at nid 20 and 25 on hdaa1
pcm5: <Realtek ALC671 (Rear Analog Line-out)> at nid 33 on hdaa1


Change need restart of playing application !
current: hw.snd.default_unit: 3

HDMI: sysctl hw.snd.default_unit=2
Speaker: sysctl hw.snd.default_unit=3


