In oud and Barbat the angle between neck and head stock is very acute , which causes a hyge amunt of tune force the stying pressed on the nut and make some disorders in tune.
In this case, chords stick in their grooves on the nut and sometimes tune force does not tramsfer to the useful pavt (vibration part) of the string or has a creak sound which gradually (in several month) will tear the strings in the location of nut.
On the other hand, this form prevents the player from access to a precise and hearty tune, and altogether player should waste too much time to tune his/ her instrument.
The innovations which are performed to make the above problems easier are:
- Aset of rollers which are installed behind the nut , resolve all the above – mentioned problems.
- One support is supplied between every pair of vollers, so that seesaw of tune on one string does not aftect other strings.
The designing of this innovation is so that it can be praticed on oud, Barbat and the same family of glees with every number of strings.
Its pahern is designed in the Mohammadi brothers workshop, and is registered in the Bureau of invention Registry and Industrial ownership under the Licence number 58263.