Thank you for your advice.
but when I turn speaker on by "force_loudspeaker_on" , it seems that headphone is also killed.
and I can not mute speaker by "force_loudspeaker_off".
#I use this applet to keep speaker silent when I am listening musics on N810 and suddenly headphone is plugged out.
#yeah , there is a nice app for muting speaker and pausing multimediad when headphone is plugged out.
#but this applet allows me to mute speaker 'perfectly' and to enjoy fake 4ch surround sound .