gStrings is a chromatic tuner application measuring sound pitch and intensity. It will let you tune any musical instrument (violin, viola, violoncello, bass, guitar, piano, wind instruments, your own voice/singing). Features include: 1. multiple built-in instruments and tunings, 2. support for user-defined custom tunings, 3. a long list of built-in temperaments (just, pythagorean, meantone, comma, etc.), 4. support for user-defined custom temperaments, 5. orchestra tuning (shifting/redefining tone frequencies), 6. pitch pipe, and many more. If you were looking for a guitar tuner, try it! Thank you note: most of the historic temperaments were included courtesy of NetCat AG.