Charity Case Pt.2: Side Crack and High Action
Instruments- discuss specific features, luthiers, instrument problems & questions
notsothoreau, Assuming that the melody strings were not replaced prior to re-tuning this would be expected because you lowered the melody pitch five semi-tones in dropping the melody string(s) from "d" to "A", thus lowering string tension significantly. A typical string set for a D-A-AA tuning would be 22w-14-14,14 gauge strings ("w" meaning wound string and gauge meaning x/1000"). String tensions would lie approximately within the range of 13.5 to 16.5 pounds. If the melody strings in this set up were raised from an "A" to a "d" you can appreciate that the tension would rise above the optimum, making it harder to fret (with a perceived "higher" action) and given that the sectional density of the string is above its optimum it would not "sound right" (part of that would be the tension's affect on intonation relative to the middle string of the same gauge being under a lesser load).
If by "action" you mean the physical properties of string to fret crown gaps, it may be that your dulcimer's action is not at all that bad and the perception of "high action" in D-A-dd is due to the out-of-spec tension increase of the melody pair. Your re-tuning of the melody strings to "A" for a D-A-AA tuning did not affect the tension of the middle and drone strings, thus the perception of improved action rests solely on the lowered tension of the melody pair.
There's nothing wrong with a D-A-AA tuning. Many use nothing else. About the only downside is that D-A-dd has become more popular in general - meaning tabs and sheet music are more readily available (nevertheless there is ample material for the more traditional tuning).
Should you decide at a future date to give D-A-dd another go, consider changing the melody strings to 12 or even 10 gauge. The melody string tension will be close to what you have with the current 14 gauge strings tuned to "A" so the 10 or 12 gauge "d" strings should ring better than before. You still have the option of tuning melody strings down from "d" to "A", but this time around the tension will be the lowest you've experienced so far, with the downside being a loss of volume and tonal balance (whether or not that is "significant" is primarily a matter of individual perception).
I hope this has been helpful to you and that I did not lose you in trying to explain some of the physics of the issue. No problem at all with your chiming in here. In fact, you brought up another aspect of things affecting action and intonation which pretty much has been the topic of this thread.
updated by @jim-hedman: 04/01/18 12:36:45AM
