Audio through headphone jack

When a HDMI cable is connected to the Raspberry Pi, audio is defaulted to going over HDMI and does not play out of the audio jack.

To set audio to default to the headphone jack, open a Terminal and enter the following command
amixer -c 0 cset numid=3 1

Test this has worked by plugging in headphones or speakers into the jack and entering the command
aplay /usr/share/scratch/Media/Sounds/Vocals/Singer1.wav