The melodic language of the stringed instrument is closely related to their vocal music and to their speech patterns, as is the case in much African music. It is a language that emphasizes on the tonic and fifth, with quavering pitch-play, especially pitch-flattening, around the third, the fifth, and sometimes the seventh. This is the language of the blues.
krakebs or Qraqab
Gnawa music is characterized by instrumentation. The large heavy iron castanets known as qraqab (or krakebs large iron castanets; Ar. قراقب) and a three -string lute known commonly as a hajhuj (or gimbri) are central to Gnawa music.(Schuyler, 2008) The rhythms of the Gnawa, like their instrumentations are distinctive. Particularly Gnawa is characterized by interplay between triple and duple meters. The “big bass drums” mentioned by Schuyler are not typically featured in a more traditional setting. (Schaefer, 2005)
Gnawa have venerable stringed-instrument traditions involving both bowed lutes like the gogo and plucked lutes like the gimbri (Ar. چنبري; also called hajhuj, Ar. هجهوج or "sentir" Ar. سنتير), a three-stringed bass instrument. The Gnawa also use large drums called tbel (Ar. طبل ) in their ritual music. The Gnawa hajhuj has strong historical and musical links to West African lutes like the Hausa halam, a direct ancestor of the banjo.
Gnawa hajhuj players use a technique which 19th century American minstrel banjo instruction manuals identify as "brushless drop-thumb frailing". The "brushless" part means the fingers do not brush several strings at once to make chords. Instead, the thumb drops repeatedly in a hypnotically rhythmic pattern against the freely-vibrating bass string producing a throbbing drone, while the first two or three fingers of the same (right) hand pick out, often percussive patterns in a drum-like, almost telegraphic manner.