This site is mainly interested in tunings.

But string gauges and scale lengths are important for two reasons:

• It's a big help in sorting out the rubbish published elsewhere on the web. Many of the tunings published at well-presented sites are just not physically possible. (It's even helped occasionaly in correcting incorrect information published in good faith on this site! See the disclaimer.)

• It's critically important to use compatible gauges and tuning on many instruments. A mismatch will at least fail to do the instrument and player justice, and at worst destroy the instrument.

The gauge, tension and length of a vibrating string and its frequency of vibration are related by a very simple mathematical relationship:

• String mass per unit length, string tension and string length vary in direct proportion, and in inverse proportion to frequency.

That is, double the mass per unit length and keep length and frequency the same, and you need to double the tension. That makes sense; If you (thought experimentwise) split the string in half and had both bits vibrating side by side, each bearing half the tension, what's changed? If again in your thoughts you weld them back together while still vibrating, what's changed?

Or, if you halve the length of the string and keep the tension and string gauge the same, the frequency doubles. That's going up an octave... which is why fret 12 is halfway up the neck.

It's why you need slimmer strings for higher pitches, to keep the tension of all of them about the same and the instrument playable. It's why you need to use a stronger, square-neck dobro for steel guitar, which uses heavier gauge strings. It's why violin strings are shorter and thinner than cello strings.

See also

• high tech highs
• scale