(23-12-2008, 13:03)poPPie Wrote: พี่กฤษณครับ
ไหนๆ ก็โชว์โครงสร้างภายในกันแล้ว อยากทราบว่า กีต้าร์ที่เราสั่งทำขึ้นมา
เวลาที่เค้าจูนเสียงหรือถ้าต้องการทำให้เสียง ทุ้มหรือแหลมมันดังขึ้น หรือ
ปรับ Balance มันต้องตัดหรือเฉือนส่วนไหนออกครับ
ขอบคุณครับ
เพื่อนๆ คนไหนที่มีประสพการณ์ จะเข้ามาตอบไว้เป็นความรู้ก็ได้นะครับ
น้าป้อปปี้ถามง่ายแต่ตอบยากครับเพราะการทำกีต้าร์ handmade มันเป็น art
ไม่ใช่ science การทำ voicing นี่ผมให้ตา Dana Bourgeois มาตอบแทนก็แล้วกัน
EXCERPT FROM ?Still Voicing, Still Dreaming?, Dana Bourgeois,
American Lutherie #61, Spring 2000.
The way a guitar sounds is primarily the result of two factors, design and wood selection. Once these essential choices are made, all you can do is either ruin or optimize. The act of voicing is the means by which you try to optimize the result. On a certain level wood selection is the first step in this process. When building 500 guitars a year, which is 40 per month, we buy the best wood we can get, this is the wood we have, and we learn to work with it. We prune out the material we don?t want to use, and try to make the best guitars with what is left. Each one is different. In reality, we are like chefs working with the ingredients that we can find at the market.
So the first part of voicing is actually selecting the wood. The second part of voicing is thicknessing the top plate, which we do after the rosette has been put in and the sound hole has been cut. Four different people are actually involved in the voicing process at four different stages. I don?t participate in either of these first two steps, other than at the approval level.
We usually thickness our tops in batches, and we basically thickness to flexibility. We run a bunch of tops through the wide belt sander and as they come out we flex them, and when they feel about right we set them aside. If they feel stiff we send them through again and take off another five thousandths of an inch. Removing top mass has an exponential effect on stiffness. If you remove 5% of the top you'll change the stiffness by more than 5%. It?s a process of doing that until all of the tops feel about right.
The third stage of voicing is brace carving. Our braces are pre-machined. We have a standard X, a standard tone bar, and a standard upper transverse bar. And we have standard stock from which we make the finger braces. For the past year I have been doing all of the brace carving myself. When I get the tops the pre-shaped braces are already glued in place. The ends of the X are sanded to a given height. Not much else is done.
I hold the top at a couple of known nodal points and tap over the braces. I draw little circles on the top at the nodal points, so I can visualize where they are. I tend to hold from two different points, one on the bass side and one on the treble side.
Since the top is asymmetrically braced, the nodal points are going to be in different places from side to side. I will also hold the guitar above the sound hole, but I don?t consider this as important. As I work I continually flex the top to help gauge my progress.
I listen to the tap tones, then alter the bracing with chisel and finger plane, and then listen to the tap tones again. I don?t care about the specific pitch at any point. Some people tune to certain pitches, particularly in the violin world. Whatever they are doing seems to work for them and produces wonderful instruments, but that is not my approach.
I listen for musical qualities that are very difficult to describe. I care what it sounds like when I tap over the bridge area but I also want to hear what the other braces sound like. How clear is the tone? How musical does it sound? As I remove wood from the braces I?m always asking myself, "Is this as good as it can be? Or, can it be a little bit better?" If I decide that it can be better the question becomes, where should I remove wood? That?s where experience takes over. I don?t really have a rigid method. The answer is that I remove wood where it seems like there?s too much of it. There are certain things I?ll do if I am in a groove. And there are others I'll try if I feel that a standard approach isn?t working. Constant flexing helps with the decision process. Remember that I am working on a batch at a time. Once I find a groove I can hopefully maintain it throughout the batch.
I tend not to focus on one brace at a time, but rather to move all around while I am listening and take a little bit here and a little bit there, working the whole top, until I can tap over every brace and get clear notes everywhere. I like to work quickly so I can remember where I started out. And I try to fall within a flexibility range that I know is correct for the style of guitar that I am making. Ideally I want to be able to hold a top and tap it anywhere and get clean notes. In reality that?s not going to happen, but if I can hold and tap in a variety of places and mostly get clean notes, that?s what I?ll actually settle for. The whole process of brace carving only takes about eight minutes. These eight minutes probably add more value to the guitar than any other eight minutes in the construction process. Lastly, I'll try to sand these braces without undoing what I just did. I try to work as cleanly as I can so I don?t have to sand the top braces very much. I use little sanding sticks and pieces of 80 grit paper, then I'll take everything down to 120. I am more concerned about what I can see through the sound hole, and I'll sand that to 180.
It?s an interesting phenomenon that in an X brace system there are a lot of triangles. The most rigid 2 dimensional geometric shape is the triangle. The triangles are made by the rim of the guitar and the braces. In an x braced top you will find one triangle on the bass side and another on the treble side, and these are going to be your rigid planes. On the bass side, I am concerned with trying overcome the triangle?s inherent rigidity. That is why I work a lot on the lowest part of the X brace, which is the stiffest member of that triangle. You are not going to loosen up the leg of the triangle that is determined by the rim, so you must work on the brace. A fourteen-fret dreadnought, for example, usually produces its deadest tap tones when held by the treble side and tapped on the bass side, so I work to bring life to the bass side. This is accomplished by selectively cutting down the lower part of the X brace. This may seem counterintuitive, since dreadnoughts are supposed to have good bass response. But in reality, traditionally braced guitars are lacking in a fundamental response low enough to properly support the note at the open E string, let along a dropped D. For that reason most open A strings sound better than the open E. I find that a little tweaking in this area helps dial in the note on the open string, without muddying the overall tonality. This is analogous to using a parametric equalizer as opposed to using a graphic equalizer. By the way, on many of my models only the bass side of my X braces is scalloped, and this is true of the dreadnought. My OMs are scalloped on both sides, which has the effect of using a graphic equalizer on the entire lower range. You also have to deal with the open string effect here, so here?s where you haul out the "parametric equalizer" again
http://www.pantheonguitars.com/
ตอนที่ช่างสมชายทำเจ้า "Apple" ให้ผมก็ใช้วิธีจูนแบบนี้ครับ
Search
Member List
Calendar
Help
![[-]](http://www.NimitGuitar.com/mybb/images/collapse.gif)
??~@_@
![[Image: hd28-scallop.jpg]](http://www.dropfiles.net//files/850/hd28-scallop.jpg)
![[Image: HD-28GE.jpg]](http://www.dropfiles.net//files/850/HD-28GE.jpg)
ความรู้อีกแล้ว โฉบมาเก็บข้อมูล
