A Beginner's Guide to Audiophile

You may like to have a look here. Site explains about low, mid, high and the optimal frequency curves for headphones and has lots of headphones tests.

Understanding such concepts can be useful, especially for those of us without a high end shop nearby to try equipment. Many of us must rely on reviews and recommendations to chart a path forward. Understanding the rationale others use to describe what they’re hearing seems fundamental. 

Is there an Audiophile for dummies book out yet? That would be a fun and educational way to start.

Try this book. It's exactly what you're looking for.

I'm sending you to the conservatory - listen and remember well how real acoustic instruments and the general atmosphere sound (you can write down impressions on paper) ... and then visit the store with headphones - turn it on and compare ...

only your ears will give an answer - what to buy and what not