Mobile-review.com Audio Column No 10. Burn in of Audio Components

At first I would like to mention that we have our first anniversary today as it is issue No 10. Thank you for your messages, tweets and forum activity. Keep on commenting, writing and discussing. It motivates and gives new topics for future articles.

Recently, I received several messages on the burn in of audio components. I think that the main sound reproduction devices are headphones and speakers. As far as my domain is the headphones we will speak about their burn in.

I will start by quoting one letter outlining the personal approach to the issue of burning in:

Dear Ilya,

Thank you for your articles. That's precisely what I was looking for.

I am not an audio maniac, but I can tell good sound when I hear one.
The field of my expertise is a bit different – acoustic systems and their components. Your articles cover another subject but are very professional without unnecessary details.

I know that you are going to write an article on headphones burn in. I never found any difference in headphones (especially with earbuds) after burn in. Good monitor headphones are another issue. You can observe a slight increase in quality.

In my area burn in is a serious point, because in acoustic systems the quality increase reaches 50%. It is quite subjective though.

Bigger and heavier speakers usually require more time. Some items require half a year for burn in. Take for example B&W Nautilus.

What is burn in? Many ask this question.

I can say that it is a "softening" of the speaker's suspension, which is easily explained. New material (for example, rubber) is hard and thick. As the result the speaker is hard as well. First sounds are dry and empty. With time the material becomes softer, which positively influences the sound (especially at low frequencies) and you can hear the nuances of a recording.

In headphones this effect is not prominent.

For me portable sound and "big" speakers are very different and it's an uphill struggle to compare them. I have earbuds for the road only. At home I use big serious headphones.

My dream is Sony Qualia 004, which is difficult to find. Even if you are lucky enough the price may be quite high...

I have the only question the Internet could not answer. What is the maximum sound quality for the iPhone? What frequency, bit rate and bits can you get from it? I managed to get only 48 KHz, 16 bit and 1536 Kbps.

Let's start from the end, though it is slightly off top. Software limitations from Apple do not allow the download of files with the sampling frequency of more than 48 kHz and higher than 16 bits. The bit rate of 1536 Kbps results from the multiplication of the sampling frequency by supported bits with the subsequent duplication (stereo recordings have two channels after all). Despite the fact that the DA converter of iPhone can manage high resolution recordings (at least 24 bits) it does not influence the sound quality due to medium quality hardware.

I do not advise to use Apple players and iPhone for AAC or MP3, because ALAC offers a slightly better quality. If the space is not at premium, copy sound files in the highest quality. Bear in mind that MP3 on a simple Teclast T51 or HiSoundAudio Rocoo sounds better than any ALAC on iPhone. I judge from my own experience.

No we will go back to the burn in issue. Some people say that a particular headphones model may not sound well without this "magical" procedure. I never experienced dramatic changes in sound quality after burning in, which should have been the end of the story, but let's think it over first.

I will start by referring to an example of an amplifier burn in. The model in question is Ray Samuels Audio Predator combining a DAC with the headphones amplifier for around $600. The device is highly specific as it requires high quality sound source and not many people will carry a laptop or netbook around. Coupled with a decent recorder or player it can even boost 300 ohm Sennheiser HD600.

Interestingly, the manufacturer advises to burn it in during several hundreds of hours. This period should be enough to move all its components into the necessary groove and ensure the required sound. I was a bit skeptical, because one month is enough to forget the initial sound features. One of my friends decided to buy the device even without any burning in. I thought it was a good opportunity to compare two variants. While my friend was ordering his copy I was busy burning in mine. I connected it to the computer with the headphones and left it this way. After one month I managed to get the necessary burning hours and it was time to compare two Ray Samuels creations.

I did a blind test with identical volume and unfortunately I could not hear any difference. It was a head to head comparison, so my memory was not involved there at all.

You may say that my ears are not sensitive enough or the headphones could not show the difference/sound source was not of the highest quality. Everything is possible. Nevertheless, I did not hear any difference, though I tried hard.

What can you say about my experiment? For many years I used it to prove that Western manufacturers offer placebo to audiophiles. Look, during several months of normal playback (600 hours recommended by the manufacturer require 2 months and a half if you listen to the music 8 hours a day) a person will get accustomed and forget the initial sound. Is it a swindle? May be.

Do we have other explanations? For example, components in both amplifiers have been already burnt in, or the procedure did not influence them and amplifier No 3 could have displayed any change. Why not? Everything is possible.

Though I had an ear for music in those days during several subsequent years I learnt to differentiate nuances better and today the results could have been different. Headphones and sound source play their part as well. I pay attention to the headphones performance depending on other system components for a reason – in particular models iPhone and Hifiman HM-801 offer identical sound and they should not be used for such "burn in" experiments.

My other similar experiences: burning in of Ray Samuels Audio Shadow amplifier and Sennheiser IE8 had the same results. Sound quality was rather influenced by different sound sources (for an amplifier) and tips (for headphones).

I think that the conclusions are the following. When you buy headphones and do not like the sound you can believe that the burning in may help over time. It is possible, because our ears are adaptable to different sound nuances. As to the procedure itself everything depends on particular models, components involved and your listening skills. To my mind there is no much point in scientific analysis of the burning in process, at least in our articles.

Do you want to talk about this? Please, go to our Forum and let your opinion be known to the author and everybody else.