what I have learned in top bracing and construction
Posted: Mon May 28, 2012 7:35 am
A top structure need not be uniform across it . When you look at the top and how forces are applied you can use that info for your bracing. I am a traditionalist so I don't fall into a lot of fad bracing. Been there done that , With a top you have to have it on the guitar to know what you are going to get. I am talking steel string here.
After 150 guitars I can only say tapping a free plate will only tell you that you have a solid piece or a cracked piece. Once on the guitar , you can do a better job of voicing. I like to keep the top and back at least a semi tone apart. As for bracing , I do use some old style techniques. I prefer using fish or Hot hide glue , and I like to tuck braces. I also use a smaller bridge plate as Martin did pre war.
Most of my braces will fall into .275 to .300 in width. I also like them 9/16 high at the X. I don't think you can place a ratio on the top thickness and brace height at all points . The reason is that the forces applied change on the top. From the bridge to the neck block you have 2 main forces applied by the strings , A compression and B rotation. This is the area of highest load stress . From the bridge to the tail you have a tensional load. Structure can handle a tensional load better than compression so here you can be lighter.
The best thing you can do , is take information and then apply it and keep a building log. Many things about this hobby or profession is subjective , yes we have to build a box that can withstand the force applied to it, but it is the builder that will determine what and how that gets done . Keep the log and find the cause effect relationship that you like as the builder. This is what will set your guitar apart from anyone else.
we all have opinions about building but until you can actual replicate the effect you want you don't have the theory. Accept the fact we all hear things differently . After all when it comes to ears, and what we hear , it is subjective , if you want true factual information, get an oscilloscope they show the sound wave information without bias , human ears are not as exact. When we delve into subjective choices , it is in the end , like asking what is your favorite ice cream. Learning to apply numbers to the construction will help you get closer but finding what numbers are important is the journey.
I have the opportunity to look inside many different guitars. I find the old Martins most fascinating but I love to see what works. I documented many tops and find that there is no one perfect bracing example. There are many things that can make a guitar sound good or bad . Yes there are things you as a builder need to learn.
After 150 guitars I can only say tapping a free plate will only tell you that you have a solid piece or a cracked piece. Once on the guitar , you can do a better job of voicing. I like to keep the top and back at least a semi tone apart. As for bracing , I do use some old style techniques. I prefer using fish or Hot hide glue , and I like to tuck braces. I also use a smaller bridge plate as Martin did pre war.
Most of my braces will fall into .275 to .300 in width. I also like them 9/16 high at the X. I don't think you can place a ratio on the top thickness and brace height at all points . The reason is that the forces applied change on the top. From the bridge to the neck block you have 2 main forces applied by the strings , A compression and B rotation. This is the area of highest load stress . From the bridge to the tail you have a tensional load. Structure can handle a tensional load better than compression so here you can be lighter.
The best thing you can do , is take information and then apply it and keep a building log. Many things about this hobby or profession is subjective , yes we have to build a box that can withstand the force applied to it, but it is the builder that will determine what and how that gets done . Keep the log and find the cause effect relationship that you like as the builder. This is what will set your guitar apart from anyone else.
we all have opinions about building but until you can actual replicate the effect you want you don't have the theory. Accept the fact we all hear things differently . After all when it comes to ears, and what we hear , it is subjective , if you want true factual information, get an oscilloscope they show the sound wave information without bias , human ears are not as exact. When we delve into subjective choices , it is in the end , like asking what is your favorite ice cream. Learning to apply numbers to the construction will help you get closer but finding what numbers are important is the journey.
I have the opportunity to look inside many different guitars. I find the old Martins most fascinating but I love to see what works. I documented many tops and find that there is no one perfect bracing example. There are many things that can make a guitar sound good or bad . Yes there are things you as a builder need to learn.