The pan or balance knob on the channel of a mixer allows you to move or place the inputted signal on that channel between the left or right speakers. For example, if you turn the pan knob on a channel all the way to the left, then the inputted signal will only be heard out of the left speaker. Now, if you slowly turned the pan knob clockwise to the right, then you would gradually hear the inputted signal start to move away from the left speaker and more towards the right speaker. As soon as the pan knob is turned all the way to the right, you should now only hear the inputted signal out of the right speaker.