Re: Speakers and headphones are working together
If your dell laptop is anything like my older dell optiplex 745 desktop I had to actually go into the ALSA mixer settings in Lubuntu and turn down the Mono bar to 00 to turn off the internal speakers. I do not know if Ubuntu with the unity interface can access or has this same Alsamixer or not but that was how I disabled the internal speakers so I could listen to music and watch videos in peace on my headphones without disturbing the misses lol. Left and right arrow keys to move and up/down arrow keys to adjust.
"Ah, for the days when a commanding officer could dump a useless minion out the airlock without having to worry about filling in forms..." ―Captain Gilad Pellaeon