String tension

The force pulling each string to pitch, determined by its mass, its speaking length and the pitch it is tuned to.

Tension is why a long scale feels stiffer than a short one and why a heavier gauge is harder to bend: to reach the same note, a heavier or longer string must be pulled more tightly. It is also what the neck, the truss rod and the top of an acoustic are all resisting, and it is why changing gauge or tuning usually requires a setup rather than just a retune. Total tension across six strings is substantial even on a light set.

Example: tuning a guitar down while keeping the same strings lowers tension and makes the strings feel floppy and sound indistinct.

String tension

See also