My column last month, “The Biggest Lie in Audio,” sparked lots of commentary, but it also raised questions that are tough to answer. While most of the people commenting on the article here and elsewhere found it to be a welcome relief from what some have called the “faith based” approach of many audio publications, some weren’t so complimentary. A few derided science-oriented, “objectivist” writers as “narrow-minded” because they criticize audio products that don’t conform to generally accepted performance standards. Some insist that there’s no such thing as “accuracy” (they always put that word in quotes) in music reproduction, so audio writers have no basis on which to criticize outlier products.
You can’t get far into an audio forum or the comments sections of audio websites without encountering the statement “Some products that measure well sound bad, and some products that measure poorly sound good.” Depending on who said it, it’s at best uninformed and at worst a lie. And it’s a lie that sometimes sticks listeners with underperforming audio gear.
A decade ago, there was little consensus on how headphones should sound. With different brands -- or even different models of the same brand -- headphone enthusiasts rarely knew what to expect because they had only vague ideas of what was “right.” It’s a different world now, though. Thanks to scientific research (such as that behind the Harman curve), wider publication of headphone measurements, and more interaction between engineers at events such as the AES International Conference on Headphone Technology, good headphones have become common, rather than rare exceptions.
The direction of the headphone market used to be dictated by engineers with acoustical design expertise. But with Bluetooth headphones and earphones having taken over the mass market -- and all of them having at least a Bluetooth receiver and an internal amplifier, and likely a digital signal processor, too -- the chips inside the headphones now have at least as big an influence on the products as acoustical or even industrial design does. And the leader in those chips is Qualcomm -- partly because it owns the aptX audio codec, which audio enthusiasts consider de rigueur for any high-quality Bluetooth audio product.
When we’re in the midst of a global calamity, it seems like the duty of every columnist to comment on it. As an audio writer, I can claim no special insight into COVID-19 or the economic effects it will have, but this episode did make me think back to the last economic crisis -- in 2008, the year I began my freelance writing career. When it comes to headphones, the technology of that era -- only 12 years ago -- now seems as primitive as the automotive technology of 100 years ago.
Through the last several years, much discussion of headphone voicing -- how their designers tune the relative levels of the different audiobands to achieve their desired sound -- has centered around the Harman curve, the “target curve” shown to be preferred by most listeners. While the Harman curve is backed by the most extensive research ever done into headphone voicing, it’s still a long way from being a universally accepted standard, even among Harman’s own headphone brands. So we thought we’d ask some of today’s leading designers how they voice their headphones -- i.e., what their target curve is, how they arrived at that curve, and any other thoughts they might have on the subject.