Mike's Oud Forums

Bracing the 7 course oud

Jonathan - 4-1-2011 at 06:41 AM

I would like to ask for opinions on how to approach bracing a 7 course oud.
This will be my first 7 course (13 string) oud, and I really need some input.
Am I correct that the face itself does not need to change? That is, I would think that the thickness of the face in a 13 string vs 11 string oud would be the same. The face still needs to vibrate, after all, and and unbraced face wouldn't hold up even if the oud only had four strings.
But the bracing. . .
This is going to be a Turkish oud. Should I use my same bracing (which is the typical Turkish oud bracing), but perhaps make the braces a little bit thicker?
Or, should I just make the brace in front and the brace behind the bridge a bit thicker (that's where the tension is going to be centered)?
Or, should I add a supplemental brace of some kind?
Thanks a lot for your input.

Dr. Oud - 4-4-2011 at 02:54 AM

I would make the face thicker. The braces are secondary in resisting string tension. It's the face thickness that really resists the torsion, while the braces transfer the tension to the back. The strings are twisting the face around the brace node points in a ladder brace system.

Jonathan - 4-9-2011 at 10:36 AM

Thanks, Doc. I worry, of course, about deadening the sound by making the face thicker. And it would seem that most of the increased tension is going to be right at the bridge--which would mean that most of the increased force would be at the face in that area, and then to the braces in front and behind the bridge.
I've got an old 13 string that I am going to try to analyze a bit before I proceed.
I really appreciate your input.

bulerias1981 - 4-9-2011 at 02:03 PM

I'm curious about this myself. I wonder how much tension an extra course would add. What tuning will you be using?

bulerias1981 - 5-13-2011 at 08:56 PM

How is the oud turning out, Jonathan?

suz_i_dil - 5-15-2011 at 06:07 AM

I don't mean to be a luthier expert, but regarding the whole tension that represent the 11 usual strings, I don't think a single more is an issue asking to modifiy the soundboard.
At least in terms of thickness / resistance of the soundboard.
I mean for exemple, I never had any kind of problems tuning up my bass strings 1 tone up ( so 0.8 kilos X 3 = 2.4 kilos more in tension). I must say it is a really well made fix bridge oud.
A single strings should be between 3.2 to 4 kilos, so not so far from that.

Andy - 5-16-2011 at 10:18 AM

On the 7 course oud I finished in 2001, the spruce soundboard was just under 2mm thick but I used a combination of traditional bracing and fan bracing. After, 10 years it is still in excellent condition.

bulerias1981 - 5-16-2011 at 12:29 PM

Quote: Originally posted by suz_i_dil  
I don't mean to be a luthier expert, but regarding the whole tension that represent the 11 usual strings, I don't think a single more is an issue asking to modifiy the soundboard.
At least in terms of thickness / resistance of the soundboard.
I mean for exemple, I never had any kind of problems tuning up my bass strings 1 tone up ( so 0.8 kilos X 3 = 2.4 kilos more in tension). I must say it is a really well made fix bridge oud.
A single strings should be between 3.2 to 4 kilos, so not so far from that.


I was thinking the same thing actually.

Jonathan - 5-24-2011 at 11:53 AM

Thank you all for your input. Sorry for the delay in responding--it was unavoidable.
I'm afraid I've taken the coward's approach on this and am going back to the traditional 6 courses. It's easy enough to do, because I taper the neck block out quite a bit more than is necessary, and then trim back for the desired neck block width.
This is my 6th oud, and I really just haven't been exposed to enough 7 course ouds to do a good job here. I really appreciate your help. Andy--that is very interesting. If you have a picture of the bracing, I would love to see it.
So, if anybody is interested, here is where I stand with the oud. Koa. Nowhere near done, obviously. I just can't seem to get more than one oud done per year.




CIMG0002.jpeg - 101kB

Edward Powell - 5-25-2011 at 12:01 AM

Hi Jon
I had some ideas for you...
First, don't give up on you plans to build a 7... just go for it and don't worry too much. Even if you skrew it up you will learn and the next will be better ---

I don't think you need to make the soundboard any different at all... if anything, just a tiny bit heavier all around.

This is what I would do:
- make it a tiny bit heavier than normal
- then once it is done, string it up, and see how it sounds and how much the SB is warping.
- if it sounds too thick/tight, then just reach inside the soundhole and sand down some of the bracing - and also you can sound down the outer surface of the SB somewhat
- keep testing and keep thinning bracing and SB until you feel you have the right balance between sound and stability...

Furthermore you can also do this process string by string... you know on a ladder braced oud each brace corresponds to a string. The first brace (behind the bridge) corresponds to the cc string - second brace to the gg string etc etc ---so test the oud and if a particular string is too tight sounding, then reach inside and sand down it's corresponding brace.

Of course on a 7 course oud, the first brace would correspond to the top two string courses.

- - - so now, after just writing this and thinking out loud, it would seem logical that the only difference to bracing a 7 course oud would be to make the very first brace slightly slightly heavier --- all else the same as normal... this is just an intuition that just came to me as I am writing.... and it is what I would do - - - anyway, if the intuition proved wrong, you just need to reach in and sand that first brace back down a little bit later :-)

Jonathan - 5-26-2011 at 08:15 AM

Thanks, Edward, for the info. I never really knew that each brace corresponds to a set of strings. Are you saying that the treble strings correspond to the lowest brace, below the bridge? I never really thought of it that way. I will admit that I am a copyist--I see an oud I like, and I try to recreate its dimensions and brace pattern.

The problem with checking for SB bracing is that it might not show up immediately. It probably won't, in fact. And, lately, I have been putting in a pretty marked dip in the face to begin with.

I am afraid it is too late for this oud--I have just made the neck and peg box, so I am going to follow through with the 6 courses. But, I have another one not far behind--you can see it int he pic (maple and walnut), and by the time I am done with that bowl I think I will be up for tackling the project of a 7 course oud.

Edward Powell - 5-26-2011 at 09:52 AM

sure.... think of it, on an oud, the "tight" part of the soundboard is BEHIND the bridge, therefore that is where the trebles come from. (guitars are usually the opposite of this).

after the oud is strung up you look at the bridge bending, and check the SB tension by pressing and squeezing it. You know from other old and stable ouds how much flex should be there and how much bridge twist (you take into account that it will increase over time).

what I am saying is that this is all an exercise in increasing the accuracy of you guesswork - in otherwords, intuition. This is really important for makers... and the only way to get it is to try again and again. . . and be willing to skrew things up badly once in a while in the process --- it's all part of it :-)

KEEP BUILDING!