On Equalization (EQ)
Viewing glasses correct for vision imperfections - EQ corrects for hearing imperfections, and yes, you have them
You may have have noticed that most headphone reviews or discussions in forums and everywhere else on the Internet concern themselves with the frequency response of the headphones. I said “you may have noticed” because they are so ubiquitous that most people would think that it is a legitimate part of the conversation.
It is not.
Most reasonable quality headphones can be adjusted sufficiently with an EQ, and, no surprise, they will sound a lot more alike than you may expect. There are other factors which make them sound different, factors which are a lot harder to:
Measure. Read about the experience of one of the great audio designers Greg Timbers https://positive-feedback.com/interviews/greg-timbers-jbl/
Explain: if hard, or impossible to measure, it will be hard to explain. But not only that: we don’t even have a consistent vocabulary. Here is an attempt: https://www.innerfidelity.com/content/aes-headphone-technology-conference-sensory-profiling
Understand. Was it easy to go through all the above? For most people, myself included, not. And so, like with anything else, to have a good idea of what we are talking about we need to educate ourselves. And if that is hard/time consuming/expensive, let’s at least listen to what the pros have to say.
Professionals have always known that the EQ is a useful, mandatory, tool. Look at one of the huge mixing consoles they use. The majority of those knobs are EQs.
If you still believe (without testing it yourself) that there is some value in listening “flat”, or “pure”, or whatever myth there might be out there in this muddy world of audiophilia, here is an excerpt from the very unusually well written (these days) user guide of one of the best DAC & headphone amplifier around, RME ADI-2 DAC, made by professionals for professionals and for us, the amateurs:
The next part is one’s hearing abilities. Most (all that I know of) people who offer their impressions on how things sound seem to completely disregard how well they hear. Did you test your hearing? If not, read below.
I am the first to admit: using an EQ to compensate for your hearing imperfections is, unfortunately, quite hard - I won’t go into details here, yet. But there are a few EQs out there which try to help. One of them is built in some Samsung phones. It is called, at least on my S6, Adapt Sound. It is important, critical, to note that this tool does 2 jobs:
It measures your hearing and
Applies that information on top of the EQ and so for that particular headphone you use, the sound will be calibrated for the imperfections of the frequency response of the headphones as well as for your hearing abilities. Of course, mapped on a target response curve Samsung chose in this case.
The tool plays tones of various frequencies, separately on your left and right ears - very important!, and it asks you what’s the lowest volume you can still hear. Then it applies the necessary corrections, and a target EQ curve. Here is what it did for me, on my Grado 325e:
Note the significant differences between my ears - and yes, I have a bit of tinnitus.
And I don't know what target curve Samsung uses, I looked for explanations online but I couldn't find anything. It looks to me that, probably because it's a phone, they favored the midrange. And I don't understand why the final curves are not the quite the same. It might simply be that it’s not a precision tool.
Test your hearing and other tools
If you just want to understand how good your hearing is, one of the best free online tools I found are by Stéphane Pigeon, again, a professional:
Besides what one can hear, objectively, measurably, one's sensitivities - what you care about, are also very important. And many of them can be educated. Besides paying attention when you listen, trying a multitude of headphones, amps, you could even use something like https://www.trainyourears.com/. I haven't done this and so I can't recommend it based on my experience, but the point is that you can train your hearing.