Intonation on hammered dulcimers - quick fix?

[The Mousetrapezoid]

Hello, all:

I have a question about intonation on the strings that cross the treble bridge. When a course is consistently sharp on one side of the bridge and consistently flat on the other, I'm guessing that that means the bridge is not positioned correctly, but is there a "quick fix" to shorten the flat segment of each string of the course, to achieve the correct intonation for both segments? (Okay, if "segment" isn't the correct terminology, please tell me what to call it!)

Also, just out of curiosity, is there such a thing as a hammered dulcimer with floating bridges (treble and bass, not the one-course or two-course bridges), or are the treble and bass bridges always glued to the soundboard?

Thanks in advance for any advice!

Sharon

[mrchips]

Basic HD bridge and tuning issues.

The treb bridge is positioned so there is a 5th interval between the notes on each side. IE: D on the right and the A above D on the left. Things that can cause this to be off are the bridge out of position. Easy check is to check a course or 2 above and below the notes that are "off. If they're fine then the bridge is in the proper position. The reference line is the center of the rod on top of the bridge, some are Delrin and some are metal. The fifth interval works by having the string a constant mass from one side rail to the other. If there is a bit of the loop wrap past the side rails or some crap on the string then you wont ever get the pair tuned. If the notes one course above and below are right then the problem IS NOT a moved bridge. Look for trash or anything that is different where the wire crosses the rod or the side rails.

Its rare you will ever have to move the bridge but if yours is out of position its not hard to move it. Its held in position completely by string tension. On rare occasion the bridge may have "welded" to the top due to the pressure fusing the finish on the top to the bridge bottom. The easy way is to down tune all the strings a note or 2 to reduce the pressure. There is no need to actually tune exactly. Now tune only one wire at each marker dead on on the right side. Check the left side. If its sharp then the bridge needs to go right, flat-go left. To actually move the bridge use a new unsharpened pencil and put the eraser against the opposite the way you want to go against the bottom and GENTLY tap. A movement you cant even see will change the tuning more than you think. After each tap re-tune the right side and repeat the above as many times as it takes. If the bridge is welded as above you may have to tap it a bit harder to break that weld. Once you have one wire at each marker dead on on each side then tune the whole thing up and youre done. In most cases the bridge should be absolutely straight but Ive seen a few where the right spot will put a very slight curve to the bridge.

The higher courses will often stick a bit on the bridge rod throwing off the tuning. There are a number of tricks to deal with the stickeys. One is to lift the string clear of the rod then gently setting it back. All you need is a gap about as big as the thickness of a sheet of paper. Another one is to tune one side dead on then check the other side. If its flat then either wack the string on the other side or simply push that side down gently. If its sharp then do the wacking or pushing on the sharp side. GENTLY push it or tap it with your finger. Im so used to how mine acts I simply tune the side opposite a tad sharp and with a couple wacks things come right to tune.

As you dont use the right side of the Bass the position isn't as critical but in general shouldn't be more than a 1/4 inch off of where the maker put it. Theres braces under both bridges with the braces positioned over them and you need to stay close to where the maker put the bridge in relation to those braces.

"Floating bridges"?? never heard that before but there is basically 2 types of HDs as far as construction goes. The most common is box construction. Thats where ALL edges of the top are glued down. The other is whats known as a floating top. On these the top is held in place only next to the tuning pins. There will be a gap between the top and both rails. As to which is the best sounding is one of the hottest debates with the HD crowd... There are bridges that are not one piece but is actually a very small bridge under each course not connected together. This is whats called chessmen bridges. Its the same deal setting the position the same but moving one wont have any effect on another course.

Hope that helps..

[Alanrichie]

is there such a thing as a hammered dulcimer with floating bridges (treble and bass, not the one-course or two-course bridges), or are the treble and bass bridges always glued to the soundboard?

Bridges, whether chessmen or single long length, are not glued to the soundboard so that they can be easily adjusted for correct intonation.

The word 'floating' is applied to the soundboard as Mr Chips noted.

[The Mousetrapezoid]

Thank you so much, Mr Chips and Alanrichie!

Sorry if my use of the term "floating bridge" was incorrect and/or confusing, but I've just recently arrived here on the planet Trapezoid as an alien from the planet Archtop. (Guitars and mandolins, that is.) In other words, I'm accustomed to using that terminology for mandolin bridges and guitar bridges, and I'm still learning the lingo as it applies to hammered dulcimers. For instance, that thing Mr Chips refers to as a "bridge rod" is what I would have called a "saddle" before I read Mr Chips's post!

Now, the floating SOUNDBOARD is something I am familiar with, since my recently-purchased Maple Valley MV-8C has one. My more-recently-purchased High Country HD-3 is a "box" type. I don't think one sounds BETTER than the other, but they do sound quite different! Compared to the throaty Maple Valley, the High Country is whisper-quiet.

The High Country is the one with the intonation issues, which involve the uppermost courses on the treble bridge, so it seems I will have to do some of that gentle tapping Mr Chips describes. Thanks again for the great advice!

--Sharon

[mrchips]

The correlation between a HD bridge and a bridge you find on a typical guitar is similar but the terminology is different. On a guitar the saddle is the piece glued to the top. The actual bridge is that white bone or micronta setting in the saddle, the part the strings actually touch. A typical HD Treb bridge is also two parts. The bridge itself acts exactly like the saddle on a guitar. What would be the bridge in terms of a guitar is the bridge rod. Note that many bass bridges dont have a rod. It can be confusing but thats one of the weird things about a HD..

[kwl]

Mrchips, I believe you have your guitar terminology backwards. The bridge on an acoustic guitar is the large piece of ebony or rosewood in which the saddle sits. It is the part glued to the top. Look at figures 1.1 and 1.2 on pages 10 and 11 of "guitarmaking - Tradition and Technology" by William R. Cumpiano and Jonathan D. Nelson.

Although this diagram is not the best, it does show the parts of a guitar:

http://www.guitartabbooks.com/freelessons/parts.htm

Ken
"The dulcimer sings a sweet song."

[The Mousetrapezoid]

Ken, you are correct: The bridge is the wooden piece that sits on the top of the guitar (and, in the case of most types of acoustic guitars, the bridge is glued on, but not in the case of every type of guitar). The saddle is the small piece, made of bone or plastic, that sits in a groove in the bridge. The strings rest on the saddle, not directly on the wooden bridge.

Mr Chips: Wow, I didn't know that some bass bridges don't have rods. How come? Wouldn't the strings eventually wear grooves in the wood of the bridge without a rod?

[JRandolph]

I once had to reposition my treble bridge with available tools right before a gig. A hammer and a long-handled wooden spoon worked nicely!

[mrchips]

Correct, the point contact pressure of a string with the tension on the average HD will in time cut through nearly anything. The combination of the tension and the small amount of back and forth movement, although real tiny, is what does it. Before delrin was around they use to use metal rods of some sorts.

That rod has a lot of effect on the tonal quality. A steel rod will be bright sounding than delrin BUT if you think you have a case of rod stickeys with delrin its nothing compared to steel strings on a steel rod. I use hard brass on mine. Brass is one of several metals that is sort of self lubercating under pressure. I did have a delrin rod there when I made it but I changed to brass to get a bit brighter sound. The stickeys are about the same in my opinion. Knowing that in time a solid bass bridge would grove out I use a 1/8 hard maple dowel on the top and for the two side rails. When the groves get bad enough I will just replace the dowels and brass rod and Im as good as new with minimum effort. I tried a brass rod on the base and the tone and sustain was reduclius so I went to the maple.

The The combination of that brass rod and the maple side rails gives me a real bright sound but the wood side rails dampen the substan nicely. Bear in mind there is no perfect rod material but delrin works better than alot of stuff. Its easy to try different rod material if you wish. As you must loosen al the strings to change a rod be aware the bridge can move. What I do is take a needle and put a dent at the corners of the bridge at each end. You wont see them unless you look for them and then they are hard to see. If the bridge moves, just put it back on the dimples and tune up. You might have to make some very minor touching up but it sure beats spending a lot of time gussing at where to start with the bridge positions.

[The Mousetrapezoid]

Thanks for the info, everyone. I am learning new things by the day here!

By the way, I emailed High Country Dulcimers about my intonation problem. Here is their response, which echoes what Mr Chips and others are saying about moving the bridge... but notice the last sentence:

"You need to "balance the harmonics". We use a padded stick. Place this stick at the base of the bridge two or three notes from the top. Tap the bridge over slightly to the "flat" side. This will sharpen up the flat side and flatten the sharp side. Check the balance in several places on the bridge,(top, middle, and bottom) to make sure it is balanced all the way. Yes, the bridges do float."

"Float" -- oh, yeah! I feel so validated.

[inomini]

The bridges have so much pressure from the strings (wires). I don't think float is the proper term. Maybe moveable with a little bit of force. Like a floating soundboard is not easily moved after the bridges and the wires are installed.

Inomini

owner of a floating and a solid soundboard HD

[mrchips]

The actual pressure holding a bridge in place is a function of the string tensions and the angle they make over the bridge. As I know those values for every string on mine i know within say 5 pounds the total force holding the bridges in place. for mine the pressure on the treb bridge is around 350 pounds total. Its also not evenly distributed all along it either. There is more down force on the high C end than the low A end. every string on it is within 5 pounds of each other but the angle over the high end is greater than the low end. That is what causes the difference. I made up a treb bridge that has a slope on it at an angle to get the down force distributed equally as much as possible but it had effects on the high end volume and tone I didn't care for so I went back to one that was the same height from end to end.

The actual values for any other Hd can be derived using a bit of math, the wire gauges, the note for that wire, the distance from the side rail to the bridge rod for both sides, and the angle the wire makes over the bridge. The actual formulas you need can be found on the net.