“You have pretty obscure taste in music.”

You're on a date with a guy. He lets you listen to his music player. He has a lot of music on there from bands that you've never heard of. You say:

You have pretty obscure taste in music.

have (adjective) taste in (something)

You can use this phrase to comment on the kind of things that a person likes. For example, if someone always buys fashionable clothes, you can say:

Rob has always had great taste in clothes.

On the other hand, if he buys strange things, you can describe it this way:

He has odd taste in clothes, don't you think?

Mostly we just say that people's taste in things is "good", "bad", "excellent", "horrible", or something simple like that. But you can also give a more specific description of someone's taste like in the example at top. Here's another example of a specific description of someone's taste:

Stark was notorious for his expensive taste in women, wine, and automobiles.

pretty (adjective)

You use "pretty" before an adjective to show how much of that quality something has. It basically means "a little more than you expected". For example:

This soup is actually pretty good.

Her latest song is pretty catchy.

obscure

"Obscure" things are not very well-known. They're only known by a few people:

I dropped out of graduate school because I didn't want to spend the rest of my life researching some obscure writer from the 18th century.

You can especially use "obscure" to talk about art, music, film, etc.