Omar Al-Mufti
Oud Junkie
Posts: 333
Registered: 3-14-2012
Member Is Offline
|
|
another question on sympathetic resonance
Dear oud friends,
Got to ask you another question on too much sympathetic resonance . Do you think sympathetic resonance (when the otherxstrings resonate while
picking one string ) has anything to do with sound hole size? Or the rosette if it is too dense? Do you think having bigger or smaller...more or less
holes will have any effect on sympathetic resonance? Do youbthink removing the rosette or replacing it with a less dense one would change anything?
I heard keeping the air inside the oud..means smaller/less holes...contributes to the sympathetic resonance.
Thanks so much in advance
|
|
|
jdowning
Oud Junkie
Posts: 3485
Registered: 8-2-2006
Location: Ontario, Canada
Member Is Offline
Mood: No Mood
|
|
If by 'sympathetic resonance' you mean 'air resonance frequency' of the bowl then you might find some of the answers to your questions here
http://www.mikeouds.com/messageboard/viewthread.php?tid=14874#pid10...
In short, sound holes do not 'keep the air inside the oud' as the air does not leave the bowl of an oud regardless of sound hole size - the air just
stays where it is inside the bowl acting like a spring to play its part in the air resonance phenomenon. At resonance frequency a plug of air
oscillates across and through the sound hole area - the resultant pressure pulsations, transmitted through the air, are picked up by the ear as sound
at the resonant frequency.
Research has found that most of the oscillating air mass through a sound hole is concentrated around the periphery of the sound hole i.e. there is
little oscillating air movement across the central area of a sound hole.
The presence of a rosette or the rosette pattern density has little if any influence on the air resonance frequency compared to an open sound hole
area. The air resonance frequency (or Helmholtz effect) is a function of air volume of the bowl, the geometry of the bowl, sound hole area or
diameter, the thickness of the sound hole at its perimeter, the number of sound holes and their geometrical relationship to each other and position on
the sound board, the flexibility of the bowl/sound board structure and the speed of sound in air (dependant upon air temperature).
|
|
|
![[*]](images/xmbprobrown/default_icon.gif){kind=icon}
