why do the tabla drums have a black spot in the middle of the drum head
Tabla The head of each drum has a central area of "tuning paste" called the syahi (lit. "ink"; a.k.a. shāī or gāb). This is constructed using multiple layers of a paste made from starch (rice or wheat) mixed with a black powder of various origins. The precise construction and shaping of this area is responsible for modification of the drum's natural overtones, resulting in the clarity of pitch (see inharmonicity) and variety of tonal possibilities unique to this instrument which has a bell-like sound. The skill required for the proper construction of this area is highly refined and is the main differentiating factor in the quality of a particular instrument.
Pirates of the Caribbean: The Curse of the Black Pearl (soundtrack) For the most part, The Curse of the Black Pearl features simple orchestration. Counterpoint is rare; most of the louder music consists of melody, simple harmony, and rhythmic figures in the low brass and low strings. Sampled drum beats including tom-toms and various cymbals are used ubiquitously in such sections. A very low, rumbling bass line was also introduced into the mix to reinforce the cello and double basses. Quieter sections tend to rely either on the string section or on sound effects. Pan flute, possibly synthesized or sampled, and claves can be heard repeatedly in the eerier cues.