This is an article that many have been asking for, given that I’ve become one of the primary sources of frequency response measurements these days. Most of the concepts that are being talked about have been simplified so as to be better understood by newbies in the hobby, so some explanations and terminologies may not be the same as the ones being used by seasoned veterans of the hobby.
This guide has been formatted in order of increasing complexity, so you’re free to stop whenever you think things get too crazy. Though, I encourage all newbies to at least sit through the first five topics.
I don’t want to go too far into the true basics since that entails a physics lesson on sound and sine-waves. Instead, I’m just going to assume that you already know what the term “frequency” is, and if not, refer to the the video below.
That is what’s called a sine sweep (or frequency sweep), where a tone of increasing frequency is played at equal volume throughout. Did you realise that some frequencies could be louder or softer than others? This is despite the fact that, digitally, each frequency is played back at the same volume to one another. That’s what a frequency response measurement captures: the relative loudness between each frequency point, played by your headphone (or IEM).