Mike's Oud Forums

Some Necessary Explanations

farukturunz - 10-23-2014 at 02:45 AM


I feel obliged to clarify the importance of the specific frequency of a brace in the context of my "Brace Tuning Method".
Many instrument makers may have been dealing with the tap tuning of their instruments to achieve a desired sound. The words "tuning" and "frequency" are related when they are in the question. Tuning means to adjust the frequency.
This relationship of the two words may lead us to a false interpretation of the "Brace Tuning" concept.
I must tell that the frequencies do not function separately.

An instrument's soundboard is a complex system which is combined of some other elements.

One of those elements is the mold on which the oud was constructed. That particular mold's size and the curvative uniqueness are very important to determine the length of each brace. The specific frequency of a brace bounds to the following parameters:

1- the length of the brace, 2- overal hight of the brace, 3- the trimming point of the edges and trimming curve + the final hight of it at the tip of the brace. 3- the specific bulk density of the wood used, 4- the Elasticity modulus of the wood used 5- the momentum of inertia of the brace's cross section.

Furthermore, in order to accomplish a good sounding soundboard we need to consider about the positioning of the braces and the Eigenfrequencies of the un-braced soundboard.

I must confess that any demand for learning my method make me feel very happy but it is not so simple to achieve. One needs to work with me for his/her own projects for a time under my supervision.

I teach this method to my assistants. They just apply the models I design for now. They are becoming familiar to the method and step by step learning how to design their own "sound models".

To understand all the caprices of the wood took me a very long period and completing my "Brace Tuning Method" set back 12 years.

With my humble fondness.

faggiuols - 10-23-2014 at 03:06 AM

goodmorning master
where I could find the text "Brace Tuning method", I am very interested in reading?
thank you very much

farukturunz - 10-23-2014 at 04:45 AM

Quote: Originally posted by faggiuols  
goodmorning master
where I could find the text "Brace Tuning method", I am very interested in reading?
thank you very much


Hello faggiuols,

I tried to summarize my method below:

Hypotheses underlying my "Brace Tuning Method" stands on solely to logic and inspirations grown of in the long process took place as I was trying to anticipate what the old masters might have done.
Known that the body of an oud virtually is a resonance box. An oud as a system is combined of a resonans box, a neck, a peg box and strings.
This resonance box must be considered as the dominantly accountable part beside the other parts. Certainly the other parts also have effects on the sound but at the first stage of the "design" I deal with the Soundboard to start with.
Accepting that the Soundboard is a fundament having some features originate from the qualities of the wood; I had a special program (WTL) written to reach all the possible designs which can be constructed on that fundamental (Soundboard).
I formulated all the mathematical relations that the program works with.
We may conceive that the soundboard is consisting of basically two elements ( once we detect the effects of the bridge, pickguard, sound holes and the rosettes, we can use them for all future analyses).
Let us come back to the two basic elements of the Soundboard: First, wooden slab; second, brace beams.
The method stands on the principle to determine all the probable vibration frquencies constituted by these two elements together and choose the eligible ones at the "designing stage".
The specific frequency of a brace beam f=b/πl^2√E/d
b: hight of the brace,
l: length
E: modulus of elasticity of the wood used
d:specific density of the wood used
We do not take in to account E and d due to their stability (for a piece of log)
The first mathematical equation on which the program works is f=b/πl^2
The second equation is Fm = Fn.f (in the square root)
Fm: compound frequency,
Fn:Eugenfrequency of the wooden slab at the center of the brace location line
f: specific frequency of the brace beam

I will go on my explanations so long as I am inquired.

With my humble fondness.

faggiuols - 10-23-2014 at 06:06 AM

it's all very interesting.
I would like to understand:
which is the matematica equation that returns the frequency of the soundboard in the middle of the brace beams?
also how do I check the overall frequency of a soundboard in project by determining the size of the brace beams
last: you say that you can change the frequency of the soundboard by changing the size of the attack brace / bowl .. how?
thank you very much

farukturunz - 10-23-2014 at 09:12 AM

Quote: Originally posted by faggiuols  
it's all very interesting.
I would like to understand:
which is the matematica equation that returns the frequency of the soundboard in the middle of the brace beams?
also how do I check the overall frequency of a soundboard in project by determining the size of the brace beams
last: you say that you can change the frequency of the soundboard by changing the size of the attack brace / bowl .. how?
thank you very much


Although I prefer to denote (Fm) as "compound frequency", its mission is to show a concrete, measurable (controlable) quantity which helps to predict the compound stiffness. This sort of denotation is handy as part of teaching procedure. My students are acquainted with this sort of similitudes. We are using a chart of frequencies to appoint a stiffness to both brace beams and the braced line of a soundboard. You don't need to calculate some proportional numerals all the time. I select some numerals through ought hundreds and hundreds alternatives by the help of a frequency chart.

The vibrating areas on the soundboard are those zones divided by the braces. The main target of the method is to create some vibrant zones proportionally related to each other in a harmony in terms of stiffness.

































faggiuols - 10-24-2014 at 12:27 AM

I may have figured it out.
what I did not understand for sure is if you proceed with your experience and sensitivity or you imposed the construction of the soundboard based on numbers derived from wood you're using.

farukturunz - 10-24-2014 at 01:20 AM

Quote: Originally posted by faggiuols  
I may have figured it out.
what I did not understand for sure is if you proceed with your experience and sensitivity or you imposed the construction of the soundboard based on numbers derived from wood you're using.


Both :)

Through its intrumentality my method shows me those numbers which will be used for dimensioning the braces. Actually the frequency stands for the stiffness. Cofusion in interpretation of the method arises on the ground that (maybe) it is named as "Brace Tuning". I don't assume to tune the soundboard. But what I am doing is "Tuning the Braces".
Of course experience and sensitivity as you say, are the key words.

Humbly