I think timbre is the first filter in one's decision of what I would call "musical niche" because there are certain instruments, certain singers and certain sounds that people's brains may not like, and that changes the way they listen to music to the point where they don't want to hear that sound or singer or instrument. It's almost like your brain has allergies for the types of things it wants your ears to hear. For example, when you're allergic to cats as a kid, you stay away from the cats in your home and other people's homes, and then as an adult you choose not to own a cat nor to go anywhere with cats. Timbre is the first thing you register, often because each thing which possesses timbre has a very distinct and unique timbre which is immediately recognizable. You hear one song and think, "Oh! That's Michael Jackson." or "Oh! That must be a flute." When you don't like something you hear, it's usually because of the way it sounds, otherwise known as its timbre. If you don't like the way something sounds, you're not about to go listen to that same sound or song again, are you? Hence, a contribution to the elimination rounds of developing your musical niche.
