What is headphone frequency response?

Measurements and Frequency Response in Headphones –

Raw Frequency Response

Headphone Testing Tips - Audio Precision

About headphones measurements and frequency response in particular

audio blog: Headphone Frequency Response Repository

My iem journey in frequency response. A comparison + quick reviews

Apos Caspian Open-Back Headphone — Kono Store

SoundID SR for Headphones: A new Headphone Tuning Standard

Can someone help me understand Harman Curves. I read that it is

The house curve: how we make our target headphone responses

What Is Headphone Frequency Response & What Is A Good Range?