From scale length to string gauge, size plays an important part in what you can expect to hear out of your musical instrument.

The physical formula for differences in pitch in relation to string gauge and tension is amazingly simple - given equal string tension, there is a one octave drop in pitch when either the scale length or the string gauge (mass) is doubled.

While size has a profound affect on the sound of a bass, bigger is not necessarily always better - particularly where string gauge is concerned. An articulate string is one that, given appropriate tension, vibrates freely. The more wraps that are applied to a string to increase its gauge, the less free the string is to vibrate.

The lower you tune the more important free string vibration becomes as any sound your instrument produces has more tonic content than just the fundamental notes being played. The following samples are of low E (41.203 Hz) and low B (30.868 Hz) sine waves. There are no harmonics or overtones that support the fundamental note. When you listen to them take note of the bland and nearly unidentifiable nature of the raw sound.

Now compare what you heard to the low E and low B as produced on a bass. Notice how full and more identifiable the notes are.

There are players that prefer to limit or eliminate overtones, mostly as an attempt to accentuate the fundamental. The easiest, best way to accomplish this is to use a slightly thinner string and reduce tension.

Getting more harmonics and overtones is a bit trickier. One way is to increase string gauge which ups tension. The down side to this approach is that increasing gauge decreases string articulation. If the intention is to make more lively a low string this may not be possible.

The best way to go about increasing tonic content is to increase scale length. If the shift in scale length is dramatic enough not only will you be able to increase comfortable string tension, you may be able to decrease string gauge as well - effectively winning twice.