There are so many possible causes of buzzing, it's very difficult to diagnose on a forum, and we'd need much more information than you have here.
In no particular order, the main culprits are:
• playing technique - either/both risha technique and fingering technique can be contributing to the problem
• uneven fingerboard - either wear from playing (you can inspect for grooves/wear) or an uneven spot somewhere on the fingerboard (sloppy
construction, shift in neck angle, or possibly humidity can all contribute)
• loose bits of string behind the bridge catching the vibration of the soundboard
• strings touching each other in the pegbox in ways that pick up vibrations
• loose rosette(s)
• loose brace(s)
• strings that are too light for the tuning/oud being used
• string pairs being slightly out of tune (won't usually create a buzz but can make a slight buzz more prominent).
• defective strings
It's nearly impossible to determine where the sound is coming from except by using something to dampen various vibrations.
If it's open strings buzzing, then it's not left-hand technique.
If only open strings buzz and not fingered notes, it's probably not risha technique either (risha-induced buzzing will mostly affect open and fingered
notes equally)
If open strings are okay, but lots of fingered notes buzz then it it may be left hand technique. If only one or two notes buzz then probably not.
If the fingerboard is uneven, then usually only very specific notes will buzz.
The most common points of wear are around the F/F# of the D string or the C/C# of the A string.
Unevenness due to warping etc. could cause issues anywhere but it's usually a range where either notes below a certain point buzz and higher notes are
fine, or vice versa - often not as specific as when it's caused by wear.
Loose bits of string - are any of the strings touching the oud face behind the bridge, even a little bit? Try muting those strings with the hand and
see if it stops buzzing. Solution is too cut the strings shorter and get them out of the way.
Pegbox strings crossing/touching: this is usually a very high-pitched buzz. Mute the strings in the pegbox while with the other hand and see if it
stops. Many solutions to this, best one I've seen is to wrap the ends of the strings with wire insulation when installing.
Loose rosettes: play and touch the rosette with the other hand to mute it - does the buzzing stop?
Loose brace: mute all the strings and tap the face in various spots. Do you hear any noises or rattling?
Strings that are too light: unusual problem unless someone uses the wrong strings (like High F tuned to low C tuning) or tunes a standard set down to
Bb, etc.
String pairs being out of tune: sometimes the extra 'wobble' of out of tune strings can exacerbate a buzz that is otherwise not really noticeable, and
out of tune strings will exaggerate any weaknesses in your risha and fingering technique as well. This might be the culprit if sometimes you have
buzzing and other days you don't, for no apparent reason.
Defectiive strings are really, really rare and are almost never the problem. But once in a while, there's a bad string.
There is also just the issue of the best tuning for a particular oud - sometimes an oud's resonant frequency just doesn't agree with a particular
tuning and this causes buzzing that goes away if you use a lower or higher tuning. There may be one of the other issues above contributing, but in the
end the oud just doesn't like a certain tuning.
As Jody suggested, test each possibility carefully, one at a time. If you go carefully through this list and make a note of everything you find,
we'll probably be able to make decent guess as to the problem. |
:
I am totally on my own here with my oud 
it sure is
a privilege.
