In the case of stringed instruments, equal temperament isn't the only compromise; there is also stretched tuning, which seeks to match the harmonics (rather tha

In the case of stringed instruments, equal temperament isn't the only compromise; there is also stretched tuning, which seeks to match the harmonics (rather than the fundamentals) of harmonically related strings to one another (in a mechanical system where the harmonics are neither perfect integer ratios of the fundamental nor constant ratios across all of the strings).