Time to muddy things up even more. Is Warren May's Kentucky Scale true just temperament or a compromise between just and equal?
I have two Warren May instruments: No 876 and No 9781 There are slight differences in the position of the first two frets between the instruments, the later build being close to equal temperament, the earlier instrument JI. Neither Warren May nor Homer Ledford used JI, intentionally. Homer did experiment with different fret positions over the years but part of that was due to his use of templates to transfer the fret positions from one dulcimer to the next. When frets are set by ear they are very likely to end up being in JI, simply because it is easy to set a fret at a point of least dissonance. You can hear when a fret position is correct for JI by comparing two strings and listening for the dissonance but there is no 'by ear' technique to find equal temperament fret positions. However, the position of frets set by ear is tied to the string gauges, pitch and action used during the setting process. Therefore, taking a template from one dulcimer and using it to build another may bring in inaccuracies. I think that the crucial thing to remember here is that historically dulcimer makers used JI, but were not aware they were doing so - it was simply that JI notes sound best when played against drones and it is easy to hear those perfect blends.
Well this certainly clears things up for me! So If I go to purchase a used or old dulcimer how can I tell just by looking at the fret board what I'm getting? I've bought several dulcimers that sound odd to me never knew the reason. I know its obvious when there extra frets but had no clue that Warrens Dulcimer's were ji. My friend just came into possession of a Homer Ledfrod she was told that it was originally built for Jean Ritchies sister that was almost fifty years ago. She got it for her 16 th birthday and only played if a few times and put it away. So would I be correct in thinking that Homer used the ji scale?
Glenda - you can spot JI (or a close to JI scale) by looking at the position of the 5th fret. It will appear distinctly flatter than equal temperament. On dulcimers where the maker used a bass string and melody a 5th above (1-5-5 DAA type tuning) the first fret may be closer to the nut than it is to the second fret (the 1st fret being the 6th of the scale). The same can be said of the spacing between the 7th and 8th frets compared to the 8th to 9th space. Dulcimers such as Homer Ledfords display this pattern. However, on dulcimers where the frets were set from a unison tuning the 1st fret may be closer to its contemporary equal temperament setting. This is because the note blend will sound like the 1st fret is the 2nd of the scale rather than the 6th of the scale. Dulcimers such as the Glens, Presnell and Melton display this pattern.