The music sounds like it is segmented into little grains, rather than flowing in one continuous piece. Not liquid or fluid. Suffering from harmonic or I.M. distortion. Some early A/D converters sounded grainy, as do current ones of inferior design. Powdery is finer than Grainy.
(1) A descriptive term for gritty texture which is desirable in certain hard-grating cheeses, though not to the point of mealiness. Parmesan and Romano exhibit a granular or grainy texture. (2) A flavor term that may be used to describe the grainlike (wheat) flavors that occur as the result of ripening.
The word grainy is usually used to describe photographs, or other images, in which areas of uniform tone on the image appear spotty or grainy. In photography this is usually due to the silver particles that make up the image clumping together.