katakofka
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Stringlength-tension in Floating bridge oud
Dear oud lovers
I have into my hands 2 ouds from the same maker (fadi matta), 2 floating bridge oud and it says the stringlenght is 60cm. The only difference in both
ouds is the top length, one is 52cm the other is 49cm. When I put pyramid oud strings on the 52cm they fit perfectly and generate the desired tension.
However, the set is loose on the 49cm top, the string tension is low. Thus, although the stringlength is similar and that by puting the bridge in a
distance to generate a 60cm stringlength the tension generated is different in both ouds and my guess this is due to the top length.
this makes me wonder about the significance of stringlength in floating bridge ouds. It seems that the top lenght has an influence on the string
tension. Does this make sense to you? Has anyone seen the same issue on different floating bridge ouds?
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Dr. Oud
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check the height of the bridge of each oud. Different heights will have different tension.
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katakofka
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Both ouds have similar bridge Doc
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Sazi
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From what I can gather, the tighter angle of the strings over the bridge on the shorter body oud effectively shortens the linear spring, thus creating
the feel of less tension. Which confusingly is kind of opposite to what you'd expect... 
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fernandraynaud
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Can you please define the terms, or provide a sketch?
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Sazi
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This may help you understand the theory better
[Link removed, as no longer functional]
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katakofka
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thanks sazi for the link...
so on 2 ouds having different soundboard length, similar bridge, and similar neck length, the tension on the bridge (the down force as it's called in
the link you provided) is not the same. So the longer the distance behind the bridge the higher is the tension on the bridge (the down force tension)
the higher is the string tension too.
What is the significance of the stringlength on a floating bridges oud taking into account the downforce tension that can be affected by the hight of
the bridge and many other factors??
On fixed bridge ouds the stringlength will help you to choose which strings to put to get the desired tension strings. On floating bridge ouds it
seems that the desired tension is affected by the bridge height and the length of the soundboard, making the stringlength info useless
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Branko
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Assume that tie-down piece is a fixed bridge and the floating bridge is a stop (like pressing on the fingerboard to reduce the length of the string),
thus whole length should be taken in to account when calculating the tension. ???
Ich bin ein Balkaner!
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DaveH
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Exactly Branko
As I understand it, Katakofka, when you say the shorter bodied oud has a lower tension, you mean that sloppy feeling on the strings? This is related
to, but not the same as, the downforce on the bridge, which is what the article Sazi linked to is concerned with.
On a floating bridge oud, the effect of a shorter body length is to give a shorter overall string length. As the tension equalises out over the
bridge, the tension in the string depends on the portion behind the bridge as well as the played section. Shorter string length will have a lower
tension at a given pitch. Simple as that.
The shorter body will give a sharper angle at the bridge, but I don't think this affects the string tension at all - even though it affects the
downforce. This might compensate to some extent for the lack of volume at the lower tension, but won't change the sloppy feel.
This is as far as I can understand, at least. Does it help?
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katakofka
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yes Dave, the sloppy feeling of the strings means less string tension.
I have seen recently an iraqi oud (fouad jihad I guess) the body is really short, however the bridge is at least 2cm height. The stringlength is 57cm
from the bridge to the nut. Putting a different bridge on this oud, such as 1cm height bridge, the strings tension is going to be lower (the string
tension after the bridge, the tension of the playable strings).
Reason why I am questioning the significance of the stringlength in floating brigdes oud. The string tension on floating bridge depends on the bridge
height, the soundboard length, whereas in fixed brigde oud the string tension depends mainly (exclusively) on the stringlength.
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Sazi
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I recently got a (Laith) Fouad Jihad oud myself, (58.5cm) and as it is the same string length as my Ayad Aswad oud and the action is similar I thought
I would use the same guage strings for both, expecting that they may be slightly less tension, as the body is shorter than the Aswad so the whole
string length is less ..., BUT! the strings are tighter feeling on the new oud. Why?
Well, the only other notable differences between the designs of the ouds are that the LFJ oud has a pegbox which is a sharper angle than the Aswad,
and the bridge is higher, which combined with the shorter body length means sharper angle of strings over bridge as well. These two things are
offsetting the shorter string length and making the tension higher!
I wanted to re-check that link I posted earlier but it seems to be broken...
I have had to tune down a semitone, which of course means it is now impossible to play with fixed pitch instruments such as ney, and my djoza player
understandably doesn't want to tune down, as he also plays with others at concert pitch
Does anyone here use a 58.5cm Laith Fouad Jihad oud at concert pitch F c d g c f ? If so could you let me know what guage strings you use, Thanks.
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Sazi
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Well it turns out that the length of string behind the bridge does NOT affect the tension of the string, neither does the break angle,which affects
the downforce to the soundboard, BUT! and it is a big but... it can affect our PERCEPTION of the tension/feel (compliance)...
here is a really interesting article on the subject
http://www.liutaiomottola.com/myth/perception.htm
The section on human perception of tension and compliance in particular, though I must say, after reading this I think oud players must be a lot more
sensitive to feel than guitarists!
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Sazi
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Does anyone here use a 58.5cm Laith Fouad Jihad oud at concert pitch F c d g c f ?
If so could you let me know what guage strings you use, I think Ive worked out a better set for my own preferred "feel" but won't know until I get
them.
I would be interested to know what others use on these particular ouds with their high bridges, Thanks.
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Edward Powell
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very interesting thread...
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Luttgutt
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A riddle!
Quote: Originally posted by Branko  | | Assume that tie-down piece is a fixed bridge and the floating bridge is a stop (like pressing on the fingerboard to reduce the length of the string),
thus whole length should be taken in to account when calculating the tension. ??? |
What Branko says sounds right! at least for a matematition like me.. : )
But anybody can solve my 2 riddles?
1- I have ordered to custum ouds from Sukar:
Both floating bridge 58,5, and have EXACTLY the SAME dimentions.
But one is Rosewood, the other is Walnut.
I use Daniel mari arabic on both, same tuning (EAADDggccff).
And I get lower tention from one of them!!?? (guess wich one  )
2- Lately, I have devised a new order on the strings/pegs relation, that I feel makes it much easier for me to tune the Oud.
In this system, the gg strings are attached to the 2 leftmost pegs (down).
And to my big surprize, the tention got MUCH lower on these strings!!
Does it mean that the "total" length from pegs to bridge is decisive??
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Sazi
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This says no...
http://www.liutaiomottola.com/myth/perception.htm
but it explains why it feels that way.
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Luttgutt
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Thanks a lot for the link, Sazi!!
P.s.
I have changes placing of gg strings (from rightmost to leftmost pegs) on 4 of my ouds (keeping the same strings, around one month old strings).
And in all 4 ouds, the gg strings FELT looser (now I am avoinding the term "tension" :-)
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Sazi
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 hehe, tricky isn't it!
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