The Multiplier, is a feature that runs along of the Star Power Meter, and the score meter in all Guitar Hero games. The feature is self-explanatory. The multiplier will multiply the amount of points earned for playing a note. Depending on the number of the multiplier it will multiply the base amount of points earned. The multiplier starts out at x1, and will advance to x2, x3, and x4. With star power in use it will double the multiplier. A multiplier is earned by successfully playing 10 consecutive notes. A multiplier is lost by missing a note or by Overstrumming.
In Guitar Hero: World Tour and games afterwards a band multiplier exists. A band multiplier is increased when members use star power within the same period of time.