Internal structure of the Afghan Rubāb

The structure of the Afghan rubāb consists of a carved and hollowed-out piece of mulberry. The cavity formed by the internal structure of the instrument is made up of three chambers or hollow volumes. This cavity is complex in nature, as explained in the thesis (The Afghan rubāb, a historical, musicological and organological study of a Central Asian lutepresented by Sylvain Roy and defended on 12 December 2017, at the University of Paris Nanterre, under the supervision of Professor Emeritus Jean During). The three chambers of the instrument's cavity play a direct part in its timbre, and are represented here by the letters A, B and C :

The primary function of chamber A, or the ‘upper’ chamber, is to lighten the neck. Even though it is not very voluminous, it contributes to the timbre of the Afghan rubāb. This is probably not significantly audible, but it should be considered in this role nonetheless.

Chamber B, known as the ‘middle’ chamber, is narrow and deep. It plays an important role in the timbre and acoustics of the instrument.

Chamber C, known as the ‘lower’ chamber, is the most important. It is often as wide as it is deep. It plays an important role in the timbre and acoustics of the instrument, and it is over this chamber that the skin soundboard is stretched. Chambers B and C communicate through a narrow open space, mentioned in the side indentations, which evokes the body of a bowed string instrument. This feature shows that the internal structure of the Afghan rubāb respects the curves of its external shape.