braces for a mountain dulcimer

[Warren May]

I looked in the Library but didn't see much discussion about bracing a MD. I'm building a couple from walnut and don't have any softwoods for bracing. Would walnut or mahogany work okay? My sides, back and top are pretty thin at about 0.10". I'm also thinking of putting a slight arch, say 25' and 20' for back and top. Is that okay? Thanks for any advice.

[Alan Carruth]

Almost anything will work for braces: the top and back aren't nearly as much of the sound on a dulcimer as they are on a guitar. I've used spruce, walnut, mahogany and butternut that I can think of, and maybe some others: I've made about 150 of these over the past forty odd years, so I've tried lots of stuff!

I usually make the top flat, just because it's easier to get the fingerboard level that way, but I do arch the back some. On the top I've started to use one cross brace at the waist, and another just above the picking cutout on the fretboard: I didn't use any top bracing for a long time, and some of them got a bit swaybacked after twenty years or so. The bracing doesn't seem to cut down on the sound... I'm not using a 'floating' fingerboard, and that might make some difference.

[Clay Schaeffer]

A well seasoned 2X4 would give you plenty of bracing, but other woods will also work. I hollow out my fretboards so they form a "box section" when glued to the top. That is what I consider to be the main brace of the top. I add a couple of light cross braces similar to what Alan does and for the same reason. Since the strings are generally anchored to the ends, the sides and back and top together take a lot of the stress

[Warren May]

Thanks, Alan and Clay. I had read that some suggest no bracing for the top which does make some sense for a hollowed or flat fretboard. For an arched one, though, it seems you would need something. I plan on hollowing the fretboard. From what I can gather, about a 3/4" x 1/2" seems to be what a lot of folks do. Without bracing, I would worry a little about it moving about over the years, especially in a harsh Mississippi or Florida environment where the dulcimers will live. My fretboard is 1 1/2" x 3/4" or thereabouts. About how much arch do you put in the back and top?

[Jim McConkey]

I hollow my fretboard and top, same as Clay, but I don't bother bracing my tops. My fretboards are basically a square U about 1/4" all the way around. I think the fretboard alone is plenty of bracing, and have never had any problems. I would leave the back flat, however, or the player will have difficulty keeping it on their lap. The top is up to you, but it is so narrow, I see very little point in arching.

[Warren May]

Thanks, Jim. I think the advice for dulcimers is "whatever works for you". I guess that's what makes them folks instruments As far as slipping out of your lap, I no longer have one so I don't think I will call it a lap dulcimer...mountain seems more appropriate for my body shape. The hourglass waist for me will be a belly cut

[Alan Carruth]

Jim McConkey wrote:
" I think the fretboard alone is plenty of bracing, and have never had any problems. "

That's what I used to think, until I had one come back because the swayback had made it unplayable. Admittedly, it was thirty years old, but still: thirty year old guitars are fine, and thirty year old violins are just getting good. After that I saw a couple more of my old ones with the same problem, to a greater or less degree. It's no real trouble to add in a brace or two, doesn't seem to hurt the sound, and easier than fixing it later. Plus, you'll sleep better o' nights.

[Chuck Tweedy]

the top and back aren't nearly as much of the sound on a dulcimer as they are on a guitar.

Super off-topic, but...
This has always befuddled me, what DOES make the sound on a dulcimer Alan?? The giant stick that acts as the FB/neck/what-not-thingy. ???????

[Alan Carruth]

Y'know, I'm not exactly sure how those things make as much sound as they do. I made a bunch of them at the beginning of my lutherie career; maybe as many as 150, although I stopped keeping track around 125, but that was before I got serious about studying acoustics, and I haven't had any around to test recently. I'm starting to make them again, and should get organized and look into things in my copious free time.

I'm pretty sure that the wood doesn't shape the sound nearly as much as on a guitar. You do need a sound box of some sort, though: the neck by itself doesn't make much noise. Hourglass shaped ones tend to have two 'Helmholtz' type resonances, especially if the waist is narrow, but they're not totally independent: blocking one of the upper holes changes the lower bout resonance, and vice versa. The back can make more sound than the top.

[Warren May]

I was making 2 dulcimers from the same walnut board. I was going to experiment a little with different bracing patterns, box sizes, bridge mounting, etc. The first one has 3 back braces and will have 2 top braces, both slightly arched. The fretboard is hollowed. I was gluing the top onto the fretboard and, not having my mind totally focused, cracked one side of the top. The top and back are a thin 0.1" or so. Fortunately, I had the other top to replace that one but will now have to find something for the second top...I'm out of walnut but have a couple of others like padauk that I might try. Would a pine top from a big box lumber work? I also have some salvaged cypress but don't like working with it since it seems dry and the dust is very nasty.

So, I think I will be cutting the soundholes on this first one before fretting and gluing on the top. This one has a pretty narrow waist. If soundholes affect the tone and volume, which configuration would be best to get a "sweet" tone with decent volume?

Although I've built several other instruments like mandolins, electric and acoustic guitars, those were mostly following plans and traditions. The dulcimer is interesting because there don't seem to be "standards" but the sound they all make is definitely recognizable as a dulcimer.

[Chuck Tweedy]

Thanks for the response Alan.

[Clay Schaeffer]

I tend to think of mountain dulcimers as being divided into two types: "guitar" type dulcimers and "zither" type dulcimers. Guitar type dulcimers have a bridge located somewhere on the soundboard and behave more like guitars for sound production. Zither types locate the saddle on the end block and as with other zithers vibrate the back as much as the top.
As players wanted more volume, I think the mountain dulcimer has "evolved" into wider body designs and soft wood soundboards and guitar type bridges, somewhat at the expense of its mellifluous sound.