Mike's Oud Forums

Tuning The soundboard of The Oud

Emir - 1-27-2014 at 12:51 AM

the shapes of free vibration modes I use for tuning soundboard...

[file]30133[/file] [file]30135[/file] [file]30131[/file] [file]30137[/file] [file]30139[/file] [file]30141[/file] [file]30143[/file]

siaka1974 - 1-27-2014 at 02:21 AM

Hello Emir,

Please tell us the frequency that you use (with picture above)

Thanks

Emir - 1-27-2014 at 03:46 AM

Hello Hatem,

Frequencies of modes (in the order):

161 Hz - 260 - 311 - 335 - 367 - 378 - 412

But I'm still working on top. frequencies and shapes will be little changed

siaka1974 - 1-28-2014 at 06:12 AM

Many Thanks Emir

SamirCanada - 1-28-2014 at 06:25 AM

That looks awsome.
So we know that the oud vibrates differently at different frequencies.
How do you know the way to modify it? and what are you aiming for when you tune the top of the soundboard?

thanks for sharing your knowlege,
Samir

hussamd - 1-29-2014 at 05:49 AM

Is there an advantage/disadvantage to having only one hole instead of 3? That should change the vibration patterns, right? How does that translate to sound.

Emir - 1-29-2014 at 03:35 PM

Quote: Originally posted by SamirCanada  
That looks awsome.
So we know that the oud vibrates differently at different frequencies.
How do you know the way to modify it? and what are you aiming for when you tune the top of the soundboard?

thanks for sharing your knowlege,
Samir


Thank you Samir. Plate tuning methods are used to control final sound quality of an instrument.
You know woods are not exactly alike so it’s not enought to just measure the thickness. I use this method (free plate method - Chladni Method) to measure vibrating properties and elasticity of the top in parallel-to-grain and across-the-grain. Same as the traditional methods of tapping, listening, and feeling the stiffnesses in a top with finger. Advantage of free plate method is that we can obtain experimental data and archive them. In addition we can control making process more accurately.

To understand whether it is the true way to modify final sound or not, makers should assess the similarities and differences between own experiences and experimental data of the tuning method.

Violin makers have used it for years. So, now they can give us more details about frequencies of vibration modes and their shapes for desired final sound of violin. Besides they can tell us which modes are important and how we should adjust them. Guitar makers also use it. There isn’t any detailed research about free oud top tuning yet. Actually I've been working on it in my workshop for a long time.
thanks,

emir

Emir - 1-29-2014 at 11:49 PM

Quote: Originally posted by hussamd  
Is there an advantage/disadvantage to having only one hole instead of 3? That should change the vibration patterns, right? How does that translate to sound.


Hello Hussam, You know dimensions of tone holes and whether They have rosette or not change Helmholtz Frequencies. In addition ouds which have 3 tone holes have a much wider frequency region of strong sound hole radiation whereas the single hole ouds. This is an advance. I don't know exact frequencies of oud but for example five tone holes vihuela have strong sound hole radiations up to about 500 Hz. Single hole instruments only have strong sound hole radiations up to about 300 Hz. (Radiation characteristics of multiple and single sound holevihuelas and a classical guitar - Rolf Bader)

To tell the truth I have no experience in how tone holes effect vibration modes. I'll try to do it as soon as possible. I guess having 3 tone holes is a disadvantage in terms of vibration properties of oud top.

thanks
Emir

theodoropoulos - 11-8-2015 at 10:51 AM

i would like to ask some questions
1)How do you use the Chladni patterns to tune the soundboard?are there specific areas in which if you remove wood,the modes change in a special way??can you tell us more?
2)is it normal to have the last mode only in 412 Hz?this must have no trebles..
3)do you have a specific series you want to follow in Hertz (161 Hz - 260 - 311 - 335 - 367 - 378 - 412) and what is the philosophy??
thank you!

jdowning - 11-8-2015 at 12:33 PM

This old paper in the Galpin Society Journal may be of interest 'Acoustical Experiments on the Lute Belly' by Ian Firth, available at JSTOR. (Google search)

If one does not have access to JSTOR via a Library or Academic Institution, papers may be read online by free registration of a MyJSTOR account. This gives free access to up to 6 articles a month from a huge range of academic and scientific journals and other publications. Very useful for research purposes.

theodoropoulos - 11-9-2015 at 08:03 PM

thank you mr jdowing :)

Emir - 11-10-2015 at 11:55 PM

I've been working on top tuning of oud several years. I have master thesis about this method but in turkish. I'm preparing document in english in brief with photos. I hope I will share it in one week.

Emir

theodoropoulos - 11-11-2015 at 04:45 AM

Thank you for your reply!!
My main focus will be on ''from which area of soundboard must i remove wood to control a certain mode''
If for example i want the second mode 20 Hz less ,from which area must i remove wood?

theodoropoulos - 11-24-2015 at 09:33 PM


i attach a photo
in this photo we see a diagramm of a violin plate and has specific areas where if wood is removed ,specific modes change.
I ask about the same diagramm in oud....

Don Z - 11-30-2015 at 07:03 PM

Love my oud, Emir!!