Post by ceadach on Aug 11, 2007 2:45:53 GMT 1
Yesterday, while reading a post in the Santouri section, I stumbled on these comments and it jogged my memory to follow up and post this as a Dulcimer Making thread.
From Ptarmigan:
"Seeing those individual bridges reminds me that I read somewhere that there was less sustain from a Dulcimer fitted with that system.
Is there any truth in that theory, do you think, or is it just an old wives tale?"
from Ceadach:
"Hmm...I don't know. Having made and played dulcimers with both chessmen and one piece bridges, I think the difference is slight at best. Having connected bridge caps is also supposed to make a difference and that will require more investigation to determine. The continuous bridges wander less when a dulcimer is transported which is a major advantage over the chessmen type."
Since writing this I've done some research into how bridges effect the tone, sustain and playability of the instrument.
I often wondered why builders began using one pieces bridges as they are usually more labor intensive to produce then chessmen. I then realized that I hadn't given this subject much thought in the all years I've been making and had just followed the plans or suggestions of others. Being the wood geek I am I couldn't just take the word of others for it as gospel apparently.
What I found out shouldn't have surprised me from the stand point of physics!
On his website veteran maker Russell Cook talks extensively about the issues with bridges. He speaks about some of the design elements incorporated in his instruments and the entire article is well worth reading.
Check it out at: www.woodnstrings.com/
To find the article click the section that says "Hammer Dulcimer Comparison". The section where he writes about bridges is labeled point #9 in his discussion of the 16-15 Ultralight model.
Russell mentions chessmen having less sustain as they impart less of energy of the strings and their neighbors to the soundboard. He also mentions how the bridges caps and timber used for the bridges can change the amount sustain. The dense these materials are the greater the sustain imparted to the rest of the instrument.
After reading Russell's article and some other things on the topic it dawned on me why I thought that connected bridges and chessmen had roughly the same impact on sound and sustain. I had what my daughter would lovingly refer to as a "Well..DUH!!" moment!!!
In all my previous instruments that had connected bridges, I used American black walnut, a wonderful wood that is a bit harder the cherry yet softer than hard maple or rosewood. The side bridges were of the same timber. Walnut has interesting acoustic properties and has the reputation for not easily warping and several makers have use it for bridges on their instruments.
The pair of instruments I made a while ago using chessmen, (including the one that I now play for gigs), I turned the bridges out of very hard yellow birch (very similar to rock maple) and the made the side bridges of hard maple. I used the same delrin bridge cap throughout save the side bridge caps in the high treble being of brass.
As a result the chessman instrument has about the same sustain as my previous instruments!! I noticed my Indian santoor had a decent amount of sustain using chessmen; here again wood was a factor, the santoor bridges are of rosewood and the bridge caps were of plastic and the side bridge caps were of brass wire similar in gauge to mandolin frets.
Trying to confirm that wood species alone could have such a large impact on the sound I turned a few more chessmen of different types of wood. I then changed a few of my existing bridges out for the new ones, tuned up the instrument and played them this way for a few days.
The results supported what others had written on this. The chessmen of walnut sustained notably less then the hard birch originals. Cherry and poplar had much less sustain and rosewood sustained a little more than the walnut.
As long as I was putting my dulcimer through all this torment , I made some one piece bridges of different woods to see how much more a wholly different type of bridge would effect the sound.
What I found was interesting. The sustain of all the different one piece bridges was slightly greater than the sustain of the chessmen of the same timber. Sawing the one piece bridges into two or three smaller sections overcame reduced the sustain a bit. But the most surprising result was that all the one pieces bridges, even divided into sections were much louder than the chessmen. The tone was also smoother and noticeably less percussive and the treble in particular seemed to benefit from the one piece bridges.
I tested different bridge caps too. I made my chessmen not to have a permanently affixed bridge cap, so they could be replaced if gouged by the strings over time. Here again the density of the material made the biggest difference in sustain and sound quality.
This test just confirmed what I'd seen in previous dulcimers earlier. Metal sustains the longest, yet the difference between different metals ( brass vs steel wire) was barely perceptible in my test. I did confirm that one piece bridge caps, just like one bridges do sustain longer but they don't effect the volume or tone the same way the one piece bridges did however.
Delrin and bone (had some scraps from making cittern bridges) had less much sustain, tuned without undue argument, but also yielded a much nicer, less aggressive tone than metal.
Using combinations of delrin and metal cap were informative; side bridges with metal cap used with delrin bridge cap have a very nice sound until about the A above middle C. Then the tone get progressively harsher toward the lower end of the compass.
I'll continue to use brass side bridge caps in the high treble and delrin for rest as it does help balance those notes again the rest of the instrument. I've seen a few other makers do this and the results justify fussing with two different materials there!
I also tested some small bit of Ipe wood, similar in density to ebony on a couple bridge caps and the sustain was further reduced but the tone was more opaque than the metal or delrin. Very hard wood bridge might be useful for the lowest notes on very large instruments that have a deeper bass.
While a number of factors determine the sound, sustain and volume of an individual instrument, the construction of the bridges are an important part of giving a dulcimer it's voice. More on bridge height, tapering and other such sophistry later.....
(Disclaimer: (And I'm not even a lawyer...
I've been repairing and making instruments for a while now. I did all these tests on one instrument so as eliminate any variables from affecting the outcome. I'm rather cavalier about experimenting on my own dulcimer, if I horribly mess something up, I can remedy it or build another one!! The results will vary from instrument to instrument. Don't alter your dulcimer without consulting a maker, repair person or your better judgment first!)
Chad,
Wood Geek
From Ptarmigan:
"Seeing those individual bridges reminds me that I read somewhere that there was less sustain from a Dulcimer fitted with that system.
Is there any truth in that theory, do you think, or is it just an old wives tale?"
from Ceadach:
"Hmm...I don't know. Having made and played dulcimers with both chessmen and one piece bridges, I think the difference is slight at best. Having connected bridge caps is also supposed to make a difference and that will require more investigation to determine. The continuous bridges wander less when a dulcimer is transported which is a major advantage over the chessmen type."
Since writing this I've done some research into how bridges effect the tone, sustain and playability of the instrument.
I often wondered why builders began using one pieces bridges as they are usually more labor intensive to produce then chessmen. I then realized that I hadn't given this subject much thought in the all years I've been making and had just followed the plans or suggestions of others. Being the wood geek I am I couldn't just take the word of others for it as gospel apparently.
What I found out shouldn't have surprised me from the stand point of physics!
On his website veteran maker Russell Cook talks extensively about the issues with bridges. He speaks about some of the design elements incorporated in his instruments and the entire article is well worth reading.
Check it out at: www.woodnstrings.com/
To find the article click the section that says "Hammer Dulcimer Comparison". The section where he writes about bridges is labeled point #9 in his discussion of the 16-15 Ultralight model.
Russell mentions chessmen having less sustain as they impart less of energy of the strings and their neighbors to the soundboard. He also mentions how the bridges caps and timber used for the bridges can change the amount sustain. The dense these materials are the greater the sustain imparted to the rest of the instrument.
After reading Russell's article and some other things on the topic it dawned on me why I thought that connected bridges and chessmen had roughly the same impact on sound and sustain. I had what my daughter would lovingly refer to as a "Well..DUH!!" moment!!!
In all my previous instruments that had connected bridges, I used American black walnut, a wonderful wood that is a bit harder the cherry yet softer than hard maple or rosewood. The side bridges were of the same timber. Walnut has interesting acoustic properties and has the reputation for not easily warping and several makers have use it for bridges on their instruments.
The pair of instruments I made a while ago using chessmen, (including the one that I now play for gigs), I turned the bridges out of very hard yellow birch (very similar to rock maple) and the made the side bridges of hard maple. I used the same delrin bridge cap throughout save the side bridge caps in the high treble being of brass.
As a result the chessman instrument has about the same sustain as my previous instruments!! I noticed my Indian santoor had a decent amount of sustain using chessmen; here again wood was a factor, the santoor bridges are of rosewood and the bridge caps were of plastic and the side bridge caps were of brass wire similar in gauge to mandolin frets.
Trying to confirm that wood species alone could have such a large impact on the sound I turned a few more chessmen of different types of wood. I then changed a few of my existing bridges out for the new ones, tuned up the instrument and played them this way for a few days.
The results supported what others had written on this. The chessmen of walnut sustained notably less then the hard birch originals. Cherry and poplar had much less sustain and rosewood sustained a little more than the walnut.
As long as I was putting my dulcimer through all this torment , I made some one piece bridges of different woods to see how much more a wholly different type of bridge would effect the sound.
What I found was interesting. The sustain of all the different one piece bridges was slightly greater than the sustain of the chessmen of the same timber. Sawing the one piece bridges into two or three smaller sections overcame reduced the sustain a bit. But the most surprising result was that all the one pieces bridges, even divided into sections were much louder than the chessmen. The tone was also smoother and noticeably less percussive and the treble in particular seemed to benefit from the one piece bridges.
I tested different bridge caps too. I made my chessmen not to have a permanently affixed bridge cap, so they could be replaced if gouged by the strings over time. Here again the density of the material made the biggest difference in sustain and sound quality.
This test just confirmed what I'd seen in previous dulcimers earlier. Metal sustains the longest, yet the difference between different metals ( brass vs steel wire) was barely perceptible in my test. I did confirm that one piece bridge caps, just like one bridges do sustain longer but they don't effect the volume or tone the same way the one piece bridges did however.
Delrin and bone (had some scraps from making cittern bridges) had less much sustain, tuned without undue argument, but also yielded a much nicer, less aggressive tone than metal.
Using combinations of delrin and metal cap were informative; side bridges with metal cap used with delrin bridge cap have a very nice sound until about the A above middle C. Then the tone get progressively harsher toward the lower end of the compass.
I'll continue to use brass side bridge caps in the high treble and delrin for rest as it does help balance those notes again the rest of the instrument. I've seen a few other makers do this and the results justify fussing with two different materials there!
I also tested some small bit of Ipe wood, similar in density to ebony on a couple bridge caps and the sustain was further reduced but the tone was more opaque than the metal or delrin. Very hard wood bridge might be useful for the lowest notes on very large instruments that have a deeper bass.
While a number of factors determine the sound, sustain and volume of an individual instrument, the construction of the bridges are an important part of giving a dulcimer it's voice. More on bridge height, tapering and other such sophistry later.....
(Disclaimer: (And I'm not even a lawyer...
I've been repairing and making instruments for a while now. I did all these tests on one instrument so as eliminate any variables from affecting the outcome. I'm rather cavalier about experimenting on my own dulcimer, if I horribly mess something up, I can remedy it or build another one!! The results will vary from instrument to instrument. Don't alter your dulcimer without consulting a maker, repair person or your better judgment first!)
Chad,
Wood Geek
