Hearing and smell are definitely not the most closely linked of the senses, but like all senses, are still woven together in the tapestry that is our physical experience as humans. An illustration of this came to light in a study done on hearing-impaired people - apparently the more severe someone’s hearing impairment is, the more their sense of smell is dulled.
The link we like to make between smell and audition has more to do with the employment of fragrance and sound in art. Music has a profound effect on the limbic system (the one in the brain responsible for our memories and emotions) just as scent does. We know this because we all have that song that reminds us of an ex, or one we hear for the first time that brings us to tears.
“Notes” as a concept also exist both in music and in perfumery; in both artforms notes need to be used in just the right way to construct a symphony or fragrance that is balanced and pleasant - use them wrong and you’ll be left with a clunky and discordant composition. Notes in perfumery are also definitely analogous to notes in music in terms of the idea of “pitch” - notes with a higher pitch are known as top notes, and those with lower as base notes.
