Mike's Oud Forums

hight of Iraqi oud bridge?

Edward Powell - 11-7-2009 at 09:27 AM

Can anyone tell me what is the average hight of an Iraqi floating bridge - in millimetres?

What is the optimum hight range: for example, should be somewhere between 11 - 15mm high??

thanks

...in my experience, if the hight is too low then there is not enough pressure on the bridge and strange buzzing sounds start occuring because the strings and bridge are not being held down firmly...

but if the bridge hight is too great, then this tends to kill the tone. It means there is too much pressure on the soundboard and the effect is to inhibit resonance....

Sazi - 11-7-2009 at 03:48 PM

Hi Edward, I just measured my three Iraqi bridges,

1) 13 mm

2) 14.4 mm

3) 15 mm

But it's not that simple... it depends on the design of the oud, i.e. the angle of the neck, or whether the soundboard is straight or curved down towards the back. (not angled, curved, as in some of M. Fadel's or Haidar Najm Abood's ouds)

"...in my experience, if the hight is too low then there is not enough pressure on the bridge and strange buzzing sounds start occuring because the strings and bridge are not being held down firmly... "

I would suggest ( though I may be wrong) that as long as you're not getting buzzing from the strings on the fingerboard, then it's not the height of the bridge but the tension of the strings, which is too low.

"but if the bridge height is too great, then this tends to kill the tone. It means there is too much pressure on the soundboard and the effect is to inhibit resonance.... "

I haven't found that to be the case, my highest bridge instrument having just as much resonance and great tone as the lowest, despite the higher downforce, but the soundboard construction, thickness and bracing, I think will have a lot to do with that.

Sazi - 11-7-2009 at 05:26 PM

You might want to have another look at this thread, the first link I gave appears to be broken, but in my most recent update is a link to an article you may find interesting and relevant.

http://www.mikeouds.com/messageboard/viewthread.php?tid=9728

Edward Powell - 11-8-2009 at 02:02 AM

thanks Sazi.... I am happy to hear this, and it is also what I was thinking, that 15mm is about the general limit, and that 12mm would probably be about the low-limit (generally speaking). This is good because on the instrument I just finished building I now have the interior bracing as light as it should ever be.... but the soundboard is 2mm or 2+mm... and I now have an 11mm bridge. The tone is still a bit too much on the bright side.... this means that I can begin sanding the top more thin from the outside, and this will both warm up the tone, as well as allow the bridge to "sink" more and more - - - thereby eventually allowing me to switch the 11mm bridge for a higher one. . . . . I will keep 13.5/14mm as my max. for the bridge to allow further natural SB warping over time - meaning that a year or two from now the bridge will be surely up to a 15mm bridge.

I will post some documentation on this new instrument soon.

Plus I intend to read that thread you suggested - THANKS!

Sazi - 11-8-2009 at 02:04 AM

Cheers, good luck, I look forward to your updates.

All the best, S

Edward Powell - 11-8-2009 at 02:30 AM

I really wonder how much we can expect a new oud's floating bridge to SINK over the course of the first 2 years?
I would like to hear from people's experience:
for example.... I put a straight-edge lengthwise along the oud's top from neck to tail, and then look at how the soundboard is 'dipping' forming an arch visible under the straight-edge. My instrument - now 3 days old - shows AT THE BRIDGE, a 2mm dip. The dip is greater at the middle of the soundboard, but I am only concerned with how much this dip is at the bridge.

I would like to know how much this dip increases with time...
for example:
-after 3 days
-after 3 weeks
-after 3 months
-after 3 years
-after 30 years

If anyone has any experience with this or would even like to offer educated guesses, I would appreciate it in now calculating how much I can afford to thin down my current soundboard.

THANKS

Ronny Andersson - 11-8-2009 at 10:11 AM

Build the sound board like Mohamed Fadel did and his son Faik does. Bent soundboard! then you will not have any problems with any dip at all. Also Yaroubs soundboards are very strong but other makers as Jihad and Munshed ouds are very inclined to get a severe dip. Munshed oud is a horror...

Edward Powell - 11-8-2009 at 10:48 AM

Quote: Originally posted by Ronny Andersson  
Build the sound board like Mohamed Fadel did and his son Faik does. Bent soundboard! then you will not have any problems with any dip at all. Also Yaroubs soundboards are very strong but other makers as Jihad and Munshed ouds are very inclined to get a severe dip. Munshed oud is a horror...


I guess you are saying that Jihad and Munshed simply use flat soundboards.

Putting a radius (dome) on the bracing in order to make a domed soundboard is a really good idea in this case... do you have any idea how much of a radius Fadel puts on the braces?

Sazi - 11-8-2009 at 03:21 PM

This is what Ronny means about the bent soundboard... this is a picture of a Fadel oud, the soundboard slopes toward the back, which is what I was referring to in my first bridge height post.

You might want to find one and check it out with a mirror inside too to see the bracing.


http://www.mikeouds.com/messageboard/files.php?pid=65977&aid=12...

Edward Powell - 11-9-2009 at 01:21 AM

Thanks so much.... this is a very revealing foto --- the main advantage seems to be how the exit altitude of the tail piece is much lower, therefore as the SB sinks there is no danger of this interfering with the critical string angle to the bridge.

However, at the end of the day, even if an floating bridge oud is made with a flat-sitting soundboard - when the soundboard bends inward - and we simply use a higher bridge - the sound result will still be the same, I am guessing. Mostly, it seems that the "pre-bent" soundboard LOOKS better because it will not show the string tension visually as a 'collapsing soundboard'. Of course, the 'pre-bent' soundboard will last longer in terms of 20 -30 years from now when decades of string tension warp the soundboard simply TOO far to be able to even put a bridge on there.... so, I can see that for the LONG LONG term the 'pre-bent' SB has mega advantages.

Otherwise, other than cosmetics, if the instrument is only meant to last 10 years or so, I can't see of any other real advantage of the 'pre-bent' soundboard. Making the SB pre-bent and trimming the rib edges correctly in order for it all to fit together properly, is a HUGE job compared to the extremely simply and easy task of bracing and fitting a totally flat soundboard. I have done some building with pre-bending soundboards and it is a major hassel. I guess for a professional builder who will be making hundreds of ouds, they would simply calculate and make up jigs for this procedure - but I am always building unique experimental instruments so to do it from scratch every time is very difficult.

The other thing to consider is that putting the 'pre-bend' on the soundboard actually 'pre-installs' tensions right into the SB. Many builders claim that this can be a very beneficial thing - and can help the sound to project more strongly. On the otherhand, if this prebending is not done completely well, then there can remain locked in the soundboard pre-tension that might not be beneficial..... therefore it is always much easier and safer to go with a flat soundboard unless we are prepared to spend ALOT of time and effort to get it completely right.

In remember RAMAZAN in Istanbul putting a slight radius on his braces (fixed bridge oud) - but he did not do anything to the rib edges to match this pre-bend - therefore- for better or worse- there is pre-locked tensions in those soundboards. FARUK makes his soundboards totally flat, but he has a extremely complicated and precise jig which trims the edges of the ribs exactly as he wants them - never totally flat - but with slight variations. He says that he puts in these variations a a way to 'encourage' the soundboard to warp DOWNWARD, and not UPWARD (which he said is one of the oudmakers' worst nightmares). So, there will be a slight amount of pre-tension in these soundboards as well.

Guitar makers on the other hand, as a normal matter of course, generally make all their soundboard and backs domed. The soundboards are are domed, and the backs use a simpler "tunnel radius")

Anyhow, thanks for these ideas! I will probably do something like this on my next instrument (after more research and thinking :-))

Sazi - 11-9-2009 at 03:07 AM

Quote: Originally posted by Edward Powell  


In remember RAMAZAN in Istanbul putting a slight radius on his braces (fixed bridge oud) - but he did not do anything to the rib edges to match this pre-bend - therefore- for better or worse- there is pre-locked tensions in those soundboards.


Yes, Ramazan's soundboards slope up at the tail end, the opposite to M. Fadel.