VSL, Tuning and Breaking Strings
Instruments- discuss specific features, luthiers, instrument problems & questions
I'd like to backtrack a bit and try a different approach. TrailDad, I do understand your question. You want to use two different sized just-tempered dulcimers to tune to the four common keys while sticking to only 1-5-5 tuning. I suspect the reason you want to stay with 1-5-5 is because that's the one tuning that your just-tempered instruments will sound 'sweet' in. Switch them to a 1-5-8 tuning for example will sound a bit sour, unless it's an equal tempered instrument. But rather than suggesting you explore a different temperament or vsl or different tuning or gauges, let's try to respond to your exact question and see where we get. :)
Ok, so let's start with assuming you are going to use the standard string setup of having a lower tonic-tuned bass string (that's what 1-5-5 indicates, after all). For ease of understanding, let's also start with the most often used 1-5-5 tuning: DAA, for the key of D .
Let's look at a visual chart of the numbered octaves on the piano, which will help us all stay on the same page:
piano octaves, numbered
There, we see that the heavy wound bass string tuned to D would be D3 on the chart.. the D below middle C. The A of the two other strings that are tuned just a 5th above that low D is A3 (still below middle C). So the typical 1-5-5 tuning for key of D is D3-A3-A3 on the piano.
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What gauge strings to use for that D3-A3-A3 tuning on a 30" vsl dulcimer? The Strothers calculator tends very slightly towards light gauge recommendations, so if the note you want is between two, choose the heavier option. (Don't just automatically choose a heavier string than the Calculator says.) The Strothers calculator for that DAA tuning on a 30" scale suggests .018 for the bass string and .012 for the other two strings. Now, .018 normally seems pretty light for a wound bass string, but then 30" is a pretty long vsl, so let's continue for a moment...
Now, let's assume you will use the SAME dulcimer to play in C which is only one step down on all strings and is easy to retune to... from DAA to CGG. Looking at the piano chart, you know you will be going DOWN just one step on all strings from D3-A3-A3 to --> C3-G3-G3, and you don't want the strings to feel too floppy. That C3-G3-G3/key of C tuning on the Strothers suggests: a .020 for the bass/C string, and .013 for the other two G strings. Keeping in mind that the Calculator may run a little too light with its suggestions, in this instance between the key of D and the key of C suggestions, we'd choose the slightly heavier option- the key of C suggestions for gauges, to ensure no slack strings. They'd certainly not be so heavy as to break when tuning up one step from CGG to to DAA.
So, for the 30" dulcimer, we'd choose the bass string to be a .020 wound string, and the other two strings to be .013 plain (unwound). That should enable you to tune 1-5-5 on a 30"vsl dulcimer for the keys of both D and C .
I'll examine the same issue but for a slightly shorter dulcimer instead, for the keys of G and A, in my next post but I have some work to do on a job right now and will try to get to it within a few hours. Hope that helps a little?
updated by @strumelia: 01/27/21 03:02:08PM