Before starting to play, the Qanun player sets the levers to create the starting maqam. Anyhow, changing a scale or modulating a pitch during playing requires the player to switch some levers back and forth with the left hand while playing. (As the video on the right side of this page shows)
While playing harmonically and rhythmically, both hands are busy but the left hand should leave the pattern to raise or lower down the levers. Therefore, the trick is to find different musical and harmonic alternatives. This limitation can sometimes force me to change parts of the musical composition or harmonic structure. So, undoubtedly, having to change levers is the main weak point of the instrument, which also can be an obstacle to playing harmonies that are outside the starting maqam or mode.
Quick modulations and accidentals can also be achieved by using the fingernail of the left thumb to press down on a string to temporarily raise its tuning. This technique noted previously as being the original technique for modulations on the qanun before the introduction of ‘urab, is called ‘afq (pressing), and aside from allowing very fast changes in pitch, it adds a familiar slight buzz, which has become a trademark of qanun taqasim.
The technical approach of the Arabic Qanun, which I have been developing, is playing with all ten fingers, rather than the traditional two index finger strumming and using it as a harmonic, rhythmic, and melodramatic instrument using a range of different sound-production techniques as an attempt to push its existing boundaries.