Adjustment of the differences in tension as compared with an open string. These differences occur inevitably when a string is touched and result in the note sounding higher than intended (the intonation of the ukulele is not pure): When pushing the string down, it is actually somewhat contracted, causing it to sound higher. Compensation (i.e., pure intonation) is achieved by prolonging the string behind the sound hole, usually with an angled bridge or a waved, notched or adjustable saddle (bridge saddle compensation). Additionally or alternatively, tension can also be raised at the nut (nut compensation). Moreover, compensation always depends on the kind of strings that are used. For instruments with steel strings, the need to compensate is by far greater than with an ukulele, because the stiffness of the strings adds to the tension.

Actually, ukuleles with saddle compensation do exist as well as strategies for nut compensation. As a rule of thumb, however, the need for compensation grows with the length of the fretboard. I.e., it is least necessary for a soprano ukulele, but can be useful with a tenor or baritone ukulele.

Examples

Lanikai
Bridge saddle compensation
LUTU-21S

Bridge saddle compensation
Big Island

Nut compensation
Hono Sound Offset Spacer