Although we’re all familiar with the idea that an A is defined (since 1939) as 440Hz, many people are less familiar with how the frequencies of all the other notes are defined. Notes an octave higher are, by definition, twice the frequency. However, this is where the simple definitions end. To hear sweet sounding chords, the frequencies of the notes should be such that that their component harmonics coincide frequently. However, it turns out that by simply choosing equally spaced frequency differences between every note in the scale, we end up with out of tune intervals (such as major thirds, minor thirds, perfect fifths, etc). This is the best overall compromise that can be done on an instrument such as the piano, which must play in any key. However, this paper by Graham Whyte (presented at the Over the Water festival in 2002) and hosted by luthier Chris Allen argues that the fact the gurdy generally only plays in a few keys allows it to be tuned in the just temperament, giving much sweeter sounding intervals. An interesting read and useful advice for someone adjusting their tangents.
Download the paper here.