I cannot use headphone output only, under ubuntu 9.10

[admin]

The problem:
I cannot use headphone output only, under ubuntu 9.10
when listening some voice/audio, voice is sent to both headphone and speaker.


solution:

install using:

aptitude install gnome-alsamixer

then, run: gnome-alsamixer,

then, click on "headphone jack sense"

thats it..