The sound system sends sound output signals to the built-in speakers and the external sound output jack.
The headphone jack is located on the left side of the computer. The headphone jack provides enough current to drive a pair of low-impedance headphones. It can also be used as a line-level output.
The headphone jack has the following electrical characteristics:
The computer has two internal speakers, one on either side of the keyboard. The computer turns off the sound signals to the speakers when an external device is connected to the sound output jack and during power cycling.