Burn in. What is it? Do you need to do it? And is it worth it?
Odds are if you read this site or others like, you probably have a strong opinion on this based on your own experiences. For those who may be less familiar, this refers to the process of breaking in a new pair of headphones by playing hours of sound on them to adjust the sound signature.
How Does Burn In Work?
So, how exactly does it work? Well first it's important to understand how headphones make sound.
Put most reductively, headphones are essentially just small scale speakers that you wear around your head. As a result, they function in almost exactly the same way.
If we’re talking about a headphone with a standard dynamic driver, you have a few key components: your voice coil and your diaphragm. When you pump an electric signal into your headphones and it reaches the coil, this component creates an electromagnetic field, which causes the thin diaphragm to vibrate - or be pulled back and forth. This motion causes disruptions in the air, which is the creation of sound waves, thus producing the sound that we hear.
The principle of burn in has everything to do with these physical components and how they produce sound. The idea is that if you play continuous sound into the headphones over an extended period of time, the consistent movement and heat will loosen up the rigidity of the diaphragm and the inner components of the headphone.
To some, this helps performance because when the components are overly rigid, they create a harsher and less pleasing sound signature.
Pink Noise Track Magic
As far as what actual sounds to use, there are varying schools of thought on the matter. Most will say pink noise is a solid bet. The reasoning here is that while white noise emits equal energy per frequency, pink noise emits equal energy per octave. So using pink noise will give you an even burn in. Others will tell you to go with a mix of pink and white, as well as random sounds, and different genres of music that will push different frequency ranges.
Time is another big variable here. While the standard appears to be about 40 hours among true believers, there really is a wide range. Some claim that you can hear a significant difference after just 10 hours, while others will swear by letting your sound roll for 100, 200 or even over 300 hours to get a desired sound!
Does Burn In Really Work?
The idea that your components will be physically affected by use and lose some of their rigidity over time is accurate. As with all technology, there is a physical component that is subject to change as all tactile material is. Now, as to whether or not this effects sound in any kind of actively discernable way?
If I’m generous, I could say it’s ambiguous.
If I’m being harsher, the research trends pretty hard toward no.
To date, there are no definitive measurements of any kind that prove a significant difference in sound quality. Many individuals and magazines have done their own frequency charting, but these are often on a scale of 1db or less - which is certainly far too small to detect differences in any kind of definitive way.
In fact, if there was a change to sound significant enough to easily be perceived after 10 - 50 hours of continuous noise, that would actually probably be a really bad sign of defect. According to Christian Thomas of USA today and Soundguys.com, the whole idea of burn in comes from quality assurance tests performed by manufacturers to see if parts could hold up after long hours of playback. The idea is that if the components degrade in any way, this means that they are unfit to use.
This is very logical and begs the question: if you claim your headphone sounds much smoother after 100 hours of pink noise, why would the driver suddenly stop degrading just because you hit your preferred amount of burn in time?
If you had loosened up the driver enough to hear that change, then it is logical to assume that it would keep becoming more so every time you use it, and the effects would become more and more apparent. So beyond just being “smoother” your headphones would probably suffer ringing, echoes, transient delays and so forth: which is obviously not optimal.
This all points to the fact that if there was an easy way to prime your headphone with sound to achieve its optimal performance, the manufacturers would probably do that in their mass production process before it ever got to the consumer. If you are getting a brand new headphone, it has probably already been optimized in every measurable way.
However, there are plenty of reputable and expert sources that claim they can absolutely hear a difference when units are burned in. For instance, fellow internet audiophile Steve Guttenberg has performed his own tests and does claim that older headphones do have a more mature relaxed sound.
Another example comes perhaps most famously from Tyll Hertsens of Innerfidelity, perhaps the most trusted individual audiophile across the internet bar none. Tyll performed an experiment where he blindly listened to two different (but identical) sets of headphones and guessed correctly in every instance which had been burned in and which had not. While the difference was clearly apparent to his incredibly perceptive ears, he also performed measurements on AKGs at different intervals of burn in time...and they were all inconclusive.
The Placebo Effect
But how can you explain people who claim that they absolutely do hear a difference when they burn in their headphones? Well, the most obvious and probably best explanation is confirmation bias. If people recommend burn in because this improved their own listening experience, you’re more likely to believe that it will do the same for you.
A second factor here is that, there in fact may be an actual change over time, but its not with the headphones - it’s with you. Oftentimes, our brains get used to the way we listen to our music, and something brand new with a different signature may be jarring. If you listen to a pair of headphones a few times, you probably will like the sound more each time because your ears and brain have adjusted, regardless of whether or not you have been playing music on them in a drawer for hours in between.
Essentially, anyone who tells you that burn in is a must is...not correct. However, if you find that you do hear a difference that makes your music more enjoyable, go ahead by all means. Whether it’s placebo or you truly have extraordinary ears, it ultimately doesn’t matter. The arbiter is always going to be whether or not you enjoy what you are listening to.
The important thing is not to deal in absolutes, as there are simply no concrete measures of the benefits of burn in, if any. Therefore, take any conversation or article about this topic with a big grain of salt. And rock on.