it is because you turn on "Independent HP"
when "Independent HP" is off, audio through hw:0,0,0 go to both speaker and headphone and when "Independent HP" is on, audio through hw:0,0,0 goto speaker and audio through hw:0,0,1 go to headphone
Simple mixer control 'Independent HP',0 Capabilities: enum Items: 'OFF' 'ON' Item0: 'ON'
**** List of PLAYBACK Hardware Devices **** card 0: NVidia [HDA NVidia], device 0: VT1708B Analog [VT1708B Analog] Subdevices: 1/2 Subdevice #0: subdevice #0 Subdevice #1: subdevice #1
it is because you turn on "Independent HP"
when "Independent HP" is off, audio through hw:0,0,0 go to both speaker and headphone
and when "Independent HP" is on, audio through hw:0,0,0 goto speaker and audio through hw:0,0,1 go to headphone
Simple mixer control 'Independent HP',0
Capabilities: enum
Items: 'OFF' 'ON'
Item0: 'ON'
**** List of PLAYBACK Hardware Devices ****
card 0: NVidia [HDA NVidia], device 0: VT1708B Analog [VT1708B Analog]
Subdevices: 1/2
Subdevice #0: subdevice #0
Subdevice #1: subdevice #1