The influence of the back and sides of a dulcimer can effect the sound almost as much as the soundboard.
Over the years I have found that there are no hard and fast rules as to what works best. This goes not only for dulcimer backs but just about everything else too!
I have made dulcimers that weighed very little for their size as well as heavier instruments. The effect of weight on tone, in my experience, is very subjective. Each piece of wood is different and the influence of design and material must be considered as a whole. This is why I have “ballpark” measurements for thicknessing wood. The final tolerances are arrived at by feel and sound.
My friend Anna is making a dulcimer as one of her home school projects. Anna is an amazing young woman who knits, weaves, contradances, plays violin, acts and does many other wonderful things. Here Anna is thicknessing a back using my shop-made thickness sander.
A week later she was laying out the positions of the back braces:
Here are a few photographs of a maple dulcimer back I recently completed. After the braces are glued on I bring them to final height with a plane and shape them with a paring chisel and scrapers:
This small scraper is great for cleaning up braces and beveling the edges of the center seam reinforcement strip. This strip of wood both strengthens the thin butt joint of the two halves of the back and adds stiffness to the back:
Here is the completed back ready to be glued to the rest of the dulcimer:
And here is passionate dulcimer enthusiast eagerly awaiting the first musical sounds this dulcimer will soon be making.