My friend and former theory teacher, Chris Bonds, sent me this picture. Chris is a violinist. The picture shows a violin fingerboard with a ruler on it. There is a bright light behind it. Note the light under the ruler. You can clearly see that the fingerboard is a bit concave underneath the ruler. Chris says it is on the order of about 1/16th of an inch maximum.
Monday, October 19, 2009
violin fingerboard - concave shape
My friend and former theory teacher, Chris Bonds, sent me this picture. Chris is a violinist. The picture shows a violin fingerboard with a ruler on it. There is a bright light behind it. Note the light under the ruler. You can clearly see that the fingerboard is a bit concave underneath the ruler. Chris says it is on the order of about 1/16th of an inch maximum.
Saturday, October 10, 2009
qin jig - for sanding, lacquering the sides
I've modified this jig since I took these pictures. Easy to make. I gave it a bigger
base (and built the jig out of only gorilla glue since appearance is irrelevant and gorilla glue is a tad less trouble than screws). So basically you have two boards that
are more or less length-wise about 2
feet long and say 6 inches high and a base that is that same length but perhaps wider
than above. I have recently glued on a bigger base so that clamps can be used with this
to hold the base secure. But one could just do it right in the first place and make it
out of three pieces of scrap lumber. Make sure the boards are smooth -- so as not
to damage the qin wood.
So one puts the qin in sideway to work on the sides. That's the
main point. Sanding, planing, lacquering, whatever. It's very useful. I even use it
as a headstop for planing the top sometimes although I'm more likely to use the traditional
bench dogs of various forms for that activity.
the qin top - slightly concave.
与古斋不语：
S.D. sez: silk strings likely to vibrate more. So ironically the user of
silk strings might need to have a bigger curve on the qin top. I think making it
work for silk strings is a necessity but never mind. the point is that the string
does go up and down (as well as side to side but never mind about that). There
needs to be a "just so" angle between a pressed string and the bridge especially
say on hui 12 (wai), string 1 (worst case) or if we claim a given string is DO, then
assume RE is the test position.
Take a good qin and a meter ruler or yardstick with a good straight edge. Put the yardstick along the line of the first string. The yardstick should rest at the ends somewhere between hui 5 and in the vicinity of the nut and hui 12 - actually slightly above the major 2nd position between hui 12 and the nut. There should be a visible gap between the top and the ruler. How big? I don't know really. With the best qin I own I see something approaching 1-2 millimeters with string 1. The most concave spot is say around hui 8 or perhaps between hui 7 and 8. It needs to gradually become less concave up to the major 2nd if you consider the string itself to be the tonic (the 12 wai position more or less in terms of qin tablature).
Note that a poor job of this can cause buzzing although said buzzing will appear most likely on the lower strings around the upper hui. The solution is drastic: redo the top. A bad qin with a bridge too high ironically might get away with not doing this at all I think. This would not be the same as a buzz caused by a high point in the qin string path.
How to do it: I think Steve's advice about this is good. Let's say you have planed the top so that you have the side to side curve and the curve from the shoulder going down to the bridge down and you are happy with it. That's two curves. You need one more.
I would put the strings on at this point before any deer-horn powder/lacquer or anything. This stage is crude. You don't want to play very much -- as you
can damage the top. However at this point you should make sure that buzzes caused by "bumps" in the wood are gone (string path is flat) and put the concave curve in too. The curve can be done with rough sandpaper slowly with a smaller sized block, or a scraper (which I view as a rough sandpaper equivalent or a very fine plane)
or probably if you are Wang Peng, you simply look sternly at the qin and it reshapes its wood without you doing anything much because it is afraid of you. A master carpenter can probably do this with a plane but I'm too chicken for that.
Slow.
Take your time. You have done a lot of hard work so no use ruining the top now.
The Yuguzhai has a great piece of advice though about all this. Don't be afraid to put the strings on and take them off. Get used to it. I use a 3 foot metal ruler to check as you can certainly see the gap, although it really isn't very big. The strings though are the ultimate test.
You put them on and check for buzzes at various notes and do a little sliding between them. The point is do this in the wood, and then put on tai, lacquer etc. Otherwise you get to take off all that hard lacquer work and do it over again after fixing the wood. And after various lacquer layers and smoothing etc. with stone or wet sandpaper or whatever, you restring and check
again. and again. and again.
Note that this is one more possible cause of buzzing of which there are so very many; e.g.,
1. top is not flat in front of the buzz point
2. top is not concave enough
3. bridge too low
4. string knot is managing to buzz on the bridge
5. something wrong with "rong kou" yarn fastener and bridge knot
6. bridge is not curved enough from front to back
7. buzz is at nut because nut is not curved enough or some other
nut problem.
8. something funky going on where qin strings tie to geese feet
9. you put on a machine tuner on the bottom and ironically it's the thing
causing the buzz
Probably 14 more possible reasons for buzzes. This is what happens when
you have a fingerboard that is 4 feet long. ...
I did a little odd research this summer about the length of acoustic strings on various instruments. The theorbo's bass fingerboard is about the only thing out there in the Western music world that has strings anywhere near as long as qin strings. Although for better or worse it seems that you actually can buy theorbo strings in Portland at several places.
Hah. Gosh. No qin string shops though. Darn.
Note well: a guqin top board needs to have a concave curve in it. According to Master Wu (Wu Ziying) starting about hui 5 or so and going above hui 12. This is especially important for the lower strings I think given that they have a bigger
density.
density.
S.D. sez: silk strings likely to vibrate more. So ironically the user of
silk strings might need to have a bigger curve on the qin top. I think making it
work for silk strings is a necessity but never mind. the point is that the string
does go up and down (as well as side to side but never mind about that). There
needs to be a "just so" angle between a pressed string and the bridge especially
say on hui 12 (wai), string 1 (worst case) or if we claim a given string is DO, then
assume RE is the test position.
Take a good qin and a meter ruler or yardstick with a good straight edge. Put the yardstick along the line of the first string. The yardstick should rest at the ends somewhere between hui 5 and in the vicinity of the nut and hui 12 - actually slightly above the major 2nd position between hui 12 and the nut. There should be a visible gap between the top and the ruler. How big? I don't know really. With the best qin I own I see something approaching 1-2 millimeters with string 1. The most concave spot is say around hui 8 or perhaps between hui 7 and 8. It needs to gradually become less concave up to the major 2nd if you consider the string itself to be the tonic (the 12 wai position more or less in terms of qin tablature).
Note that a poor job of this can cause buzzing although said buzzing will appear most likely on the lower strings around the upper hui. The solution is drastic: redo the top. A bad qin with a bridge too high ironically might get away with not doing this at all I think. This would not be the same as a buzz caused by a high point in the qin string path.
How to do it: I think Steve's advice about this is good. Let's say you have planed the top so that you have the side to side curve and the curve from the shoulder going down to the bridge down and you are happy with it. That's two curves. You need one more.
I would put the strings on at this point before any deer-horn powder/lacquer or anything. This stage is crude. You don't want to play very much -- as you
can damage the top. However at this point you should make sure that buzzes caused by "bumps" in the wood are gone (string path is flat) and put the concave curve in too. The curve can be done with rough sandpaper slowly with a smaller sized block, or a scraper (which I view as a rough sandpaper equivalent or a very fine plane)
or probably if you are Wang Peng, you simply look sternly at the qin and it reshapes its wood without you doing anything much because it is afraid of you. A master carpenter can probably do this with a plane but I'm too chicken for that.
Slow.
Take your time. You have done a lot of hard work so no use ruining the top now.
The Yuguzhai has a great piece of advice though about all this. Don't be afraid to put the strings on and take them off. Get used to it. I use a 3 foot metal ruler to check as you can certainly see the gap, although it really isn't very big. The strings though are the ultimate test.
You put them on and check for buzzes at various notes and do a little sliding between them. The point is do this in the wood, and then put on tai, lacquer etc. Otherwise you get to take off all that hard lacquer work and do it over again after fixing the wood. And after various lacquer layers and smoothing etc. with stone or wet sandpaper or whatever, you restring and check
again. and again. and again.
Note that this is one more possible cause of buzzing of which there are so very many; e.g.,
1. top is not flat in front of the buzz point
2. top is not concave enough
3. bridge too low
4. string knot is managing to buzz on the bridge
5. something wrong with "rong kou" yarn fastener and bridge knot
6. bridge is not curved enough from front to back
7. buzz is at nut because nut is not curved enough or some other
nut problem.
8. something funky going on where qin strings tie to geese feet
9. you put on a machine tuner on the bottom and ironically it's the thing
causing the buzz
Probably 14 more possible reasons for buzzes. This is what happens when
you have a fingerboard that is 4 feet long. ...
I did a little odd research this summer about the length of acoustic strings on various instruments. The theorbo's bass fingerboard is about the only thing out there in the Western music world that has strings anywhere near as long as qin strings. Although for better or worse it seems that you actually can buy theorbo strings in Portland at several places.
Hah. Gosh. No qin string shops though. Darn.
acc. to Master Dydo - 2 Wang Peng qin-making videos
All unfretted stringed instruments need a slight concavity. Silk is usually a bit lower tension than steel on a qin, so the concavity is a bit more. If you take a straight-edge to a violin (high tension strings, short string length) you will see a pronounced concavity. You can see in the Wang Peng qin-building video that he is putting in a good bit of it from the beginning. See http://www.tudou.com/programs/view/dskiDVw7FLw/ and http://www.tudou.com/programs/view/bQ2JYU5D1vQ/ . So you don’t have to ask him! The area of maximum concavity is the area of maximum possible vibration (fattest wave): hui 7.
Tuesday, July 14, 2009
Thursday, June 25, 2009
qin top woods in China
Referring to lumber used for the top of the qin in China, there are 3 kinds
that seem to come up a lot: 1. wutong 梧桐, 2. shanmu 杉, and 3. baitong 白桐.
This is not to say that other kinds of woods cannot be used. Pine, cedar, spruce
are all possibilities. But there are the three kinds most often used in China.
wutong:
See:
http://en.wikipedia.org/wiki/Firmiana_simplex
known as Firmiana simplex (scientific name) and Chinese parasol tree (English).
There are other scientific names.
shanmu:
Evert Koster found this as "shan mu". This makes sense to me:
See:
http://en.wikipedia.org/wiki/Cunninghamia.
bai tong:
See:
http://en.wikipedia.org/wiki/Paulownia
that seem to come up a lot: 1. wutong 梧桐, 2. shanmu 杉, and 3. baitong 白桐.
This is not to say that other kinds of woods cannot be used. Pine, cedar, spruce
are all possibilities. But there are the three kinds most often used in China.
wutong:
See:
http://en.wikipedia.org/wiki/Firmiana_simplex
known as Firmiana simplex (scientific name) and Chinese parasol tree (English).
There are other scientific names.
shanmu:
Evert Koster found this as "shan mu". This makes sense to me:
See:
http://en.wikipedia.org/wiki/Cunninghamia.
So basically "Chinese fir"and Cunninghamia. Not a fir though -- more like cypress. The web page says "used in temples" !!!
bai tong:
English name is "paulownia" or paulownia tomentosa to be more specific.
See:
http://en.wikipedia.org/wiki/Paulownia
The wood is very light and white in color more or less. This
wood is known in Japanese as "kiri" and has been used in furniture -- tansu-making.
wood is known in Japanese as "kiri" and has been used in furniture -- tansu-making.
Wednesday, May 20, 2009
the router railroad - a qin jig
The following pics more or less show a so-called "jig" which is above
average I suspect in complexity. Basically one has a couple of rails
and a carriage on which a router rides. This is basically a wood version
of a milling table (or could be viewed as a C&C machine lacking a computer!).
The first pic shows a small Bosch hand-held router (laminate router) sitting
in the carriage. Various clamps are used to hold the router in place. The bit
is extended manually (it's a narrow long straight bit). The next picture
average I suspect in complexity. Basically one has a couple of rails
and a carriage on which a router rides. This is basically a wood version
of a milling table (or could be viewed as a C&C machine lacking a computer!).
The first pic shows a small Bosch hand-held router (laminate router) sitting
in the carriage. Various clamps are used to hold the router in place. The bit
is extended manually (it's a narrow long straight bit). The next picture
shows the two rails with a qin top in them. This is a posed picture. In reality, the qin top needs to be braced so it won't move. The third picture is a closeup of the carriage with the router in it.
The last picture shows the nut end of the qin top and shows the various
routed out gradations in the top. The basic idea for the jig is to save
time as opposed to routing out the top "perfectly". Of course it can be used for other things and I will use it to route out some of the wood inside the qin top. In both cases, one will resort to manual tools (planes or chisels) to finish the job.
routed out gradations in the top. The basic idea for the jig is to save
time as opposed to routing out the top "perfectly". Of course it can be used for other things and I will use it to route out some of the wood inside the qin top. In both cases, one will resort to manual tools (planes or chisels) to finish the job.
The rails and "ties" were made of mahogany. It probably would have made more sense to just use a piece of MDF for the base and *draw lines* for the rails. But for some reason I couldn't make it that simple. The mahogany was scrap from a previous table project. It would be nice to figure out some more clever means of holding the router in the carriage. It needs to be clamped. There is no doubt about that. Possibly a couple of metal rails could be used to somehow do that. But I am a woodworker and not a metal worker.
Subscribe to:
Posts (Atom)
