What is burn in? Patience is a virtue

Fig.1 The part in the center with the silver colored ring around it is the diaphragm. It basically acts like a speaker, moving and pushing air to create sound.

The other day one of my friends asked me what "burn-in" is after reading the last post. In the world of headphones burn-in is a controversial issue, so let me first state that I believe it exists.

Imagine you buy a new baseball glove, it is rather stiff. The glove is not at the optimal condition for peak performance on the field, after using it for a while the player while see the leather soften up and become nice and flexible. Another example is a brand new car. The dealers, and common knowledge dictate that one should not push the engine too hard until the engine essentially had time break in.

Burn-in is another term for breaking in headphones. Perhaps one of the most important parts of the headphone to change in the burn-in process is the diaphragm. Wikipedia defines a diaphragm as: a thin, semi-rigid membrane that vibrates to produce or transmit sound waves. Bringing back the baseball glove analogy, this membrane hasn't had time to stretch out yet because sound hasn't been played long enough for it to move around and adjust, with enough use it becomes more flexible.

The debate in the audio community centers around burn-in as a myth. Many claim headphones don't burn in, that it's a psychological issue. Skeptics say people simply get used to the unique sound of a different model of headphones. There is a mountain of anecdotal evidence to suggest otherwise, too many people find an improvement in audio quality as a pair of headphones are used longer.

Burning-in is a simple procedure, one pairs the headphone with a sound source and lets it play continuously for several hours at a time. It can be music, or even white noise. The object is to move the drivers and the diaphragm so it will stretch out and be able to produce more dynamic sound than a new membrane which is initially too tight to move well enough. Burning in does not go on forever, there is likely some plateau point where the peak level of fidelity is reached.

I've tested the validity of burn-in before. Another friend of mine's bought 2 pairs of headphones a while ago, both pairs were the same model. He burned in one pair from each set respectively for two weeks while I waited patiently! So I went into the test blind and rated all the pairs from the same audio source. The results showed the burned in headphones had higher level audio quailty. The music was smoother, and less harsh than the brand new pairs.

New headphones may sound like they are underwater, after enough playing time this opens up and mellows out.

So if you buy some headphones, and find the sound is lacking when you bring it home, just hook it up to something and let it play for a few days. You might be pleasantly surprised by the improvement. This requires a little patience of course :)


Caveat: Don't expect burn-in on every headphone. I've noticed the cheap apple stock earbuds don't seem to benefit from time.