There are people who can actually see, smell and physically taste music

This is an example of a phenomenon known as synesthesia. Synesthesia is a neurologically based phenomenon in which stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in a second sensory or cognitive pathway.

While cross-sensory metaphors (e.g., "loud shirt," "bitter wind" or "prickly laugh") are sometimes described as "synesthetic," true neurological synesthesia is involuntary. It is estimated that synesthesia could possibly be as prevalent as 1 in 23 persons across its range of variants. http://en.wikipedia.org/wiki/Synaesthesia