Thank you Robin for posting an excellent just intonation tread and thanks to Bob for the calculations. I spent three days working out the math to design a 27" scale JI fingerboard. I finished the dulcimer yesterday based on my AW Jeffrey's pattern after spending 12 hours in the field planting asparagus then spent almost all night to dawn playing this dulcimer.
I expected this instrument to sound different than my equal T models but instead I was totally blown away by the sound. After over 40 years playing countless dulcimers, this was the best I ever heard. The intonation is PREFECT!. I can fret the D at the 17th fret and its in perfect tune with the open D.
I can fret the A at the 14th fret and its in tune with the open A. And here is something you can't do on equal T dulcimers. I can fret the D note on the A string at the 3rd fret and its in perfect tune with the open D and I can fret the D on the 4th fret and its in perfect tune with the open A. On equal T dulcimers your forced to choose tuning between the A or the D you can't have both. My JI model has it both ways and you can difference. Folks after you play a Just intonated dulcimer you will never want to go back to plain old equal T again...Here are a couple pics... Thanks... Robert
updated by @robert-schuler: 06/11/15 07:43:13AM