The Harman target is a frequency response curve developed by Sean Olive and Todd Welti at Harman International. It's designed to replicate how speakers in a well-treated room sound when translated to headphones — essentially, what most listeners prefer in blind listening tests.

It's not perfect, and plenty of audiophiles prefer alternatives. But it's the single most useful reference point for understanding why headphone reviews talk about bass shelf, upper midrange presence, and treble extension the way they do.