OK, audiophiles: real talk. Earphone makers seem to be either too polite or scared to say anything. And the people in the industry who should know better are only actively encouraging a ritual. So let me say it for them: Earphone burn-in is a bunch of hokum.
We'll call it 'the Beats Effect'
So funny story. I run with my headphones. Headphones you get with your iPhones have microphones. Sweat annihilates these microphones and, as a consequence, these headphones. As such, I've been buying whatever cheap shit Meei is selling that day, usually 2 or 3 pairs at a time. Subjectively speaking, they don't sound much worse than iPhone headphones. Which you're listening to MP3s or 128kbps AAC streams anyway so who cares?
Anyway. Couple weeks ago I misplaced all of my Piece of Shit Meei garbage cans. And I needed to go running. Desperate, I remembered stumbling over an old shitty pair of Sony in-ears I'd bought as a secondary pair to use with the Minidisc recorder I bought in 1996. I dug 'em out, slapped 'em in and pressed play.
Oh. My. God.
I haven't heard earbuds this good in so long I can't remember. They were probably $30 new, nearly 18 years ago. They have low end. They have high end. And they have them in approximately the same proportions as my good cans, which I've had since 2002. Just to see, I dug up some of those shitty Meeis and then some iPhone earbuds, and then some Klipsch S4s I had.
Yeah. Headphones suck now.
It used to be that you'd buy a set of headphones and they played music. Now they're a fashion statement. Now they've got flat cables and orange thingies and they're branded by J-Wow and Dr. Dre endorses them and they come with special detachable Monster Cable leads and there are so many brands now that simply didn't exist back then because they were pieces of audio equipment, not fashion items.
Take it from a former acoustician: headphones work via a physical phenomenon called "close coupling." The wavelength of a 1kHz sine wave at sea level and standard temperature is about a foot. A 500 Hz sine wave is about 2 feet and so on. It doesn't take a lot of math to determine that the lowest free-field frequency your ear canal can support is in the land of ultrasonics. At which point it pretty much comes down to whether or not your drivers have an accurate frequency response and a uniform power curve.
Hard to sell that, though. No differentiation. So we've got aluminum bodies vs. plastic bodies vs. wood bodies. This driver vs. that. This plug material vs that. And you know what? If it tests okay at the factory, it'll test okay until it wears out. I suspect "burn-in" crept into the audiophile community from the audiovisual audiophile community that used to talk about "burning in" CRT tubes and plasma displays. That was the kind of "burn in" you wanted to avoid, though.
So all these shit manufacturers perpetuate the notion that you need to do some ritualistic lovin' of their products so that they'll work better. It leverages the sunk cost fallacy - after you've spent 400 hours playing Lou Reed on endless loop into your headphones, you have damn well attached to those headphones more than if you just whipped 'em out of the package. And by participating in a community that tells you what "burn in music" does a better job, you've invested them in your product without having to make the product one iota better.
Headphones now are a pale shadow of headphones 20 or even 10 years ago. Myths such as this allow vendors to differentiate their mediocre product in the market without actually excelling.
Beats in a nutshell.