Frequency Response | 20-20KHzSensitivity | 94dB.Impedence | 16Ω

Connector | 3.5mm(golden plated)Cable Length | 1.2m

Chord & Major Journal

Earphone Journal / Earphone Knowledge

Secrets to Improve Earphone Acoustics – Burn-in

5th, May 2014

Following on from Chord&Major’s lessons on earphone specifications, we will now introduce you to the secret and exciting world of improving earphone acoustics. Today, we will walk you through what is known as ‘burn-in’.

The term ‘burn’ means to be consumed by fire. Burn-in, when discussing earphones, is the process through which music of different styles is continuously played at a low volume for a certain period of time, so as to allow the earphone’s diaphragm to reach its optimal condition. Simply put, this is done to match the earphone’s internal structure.

The principle of burn-in can be compared to the development of new car components, during which these components are used and smoothened out before being placed into the actual car. For brand new earphones, acoustic distortion (which is sound quality that is adversely affected by your environment) is likely to happen due to the earphones not having a high degree of sensitivity.

Sometimes, the diaphragms of brand new earphones are rigid and so tightly placed into earphones that prior to the burn-in process, low frequency sounds (such as bass sounds) may sound muddy or unclear, making it difficult to really enjoy the music being played. Mid to high frequency sounds, such as the human voice, may sound sharp and shrill, especially when played louder.

The following key points are all about earphone burn-in you should really know. Let’s take a look!

(1) A suitable duration:

High impedance, low sensitivity earphones have diaphragms which are more difficult to push, and as a result require a longer burn-in time. Generally, the burn-in process takes about 50 to 100 hours. Assuming a daily 8-hour burn-in time has been put in place, it would take about 7 to 12 days to finish the entire process. For low impedance, high sensitivity earphones, it is easier to push the diaphragms and therefore the burn-in time is substantially shorter at about 20 to 25 hours. If a daily 6-hour burn-in time were allowed, it would take about 3 to 4 days to complete the process. After the burn-in process is complete, earphones can be used normally and over time the tone will naturally mellow.

When conducting the burn-in process, overdoing it continuously should be avoided. A 30-minute break every 2 hours should be taken in order to prevent the deformation of the earphones’ voice coil through overheating.

The Chord&Major tonal earphone series all come with low impedance and high sensitivity and are suitable for use with mobile devices. To those who may not be as enthusiastic about the inner-workings of earphones, the Chord & Major tonal earphones help them save a lot of burn-in time and effort.

(2) Diverse music genres:

Earphones with high impedance are more difficult to push. Therefore, to effectively extend the low frequency and high frequency ranges, enthusiastic earphone users with more professional/technical expertise will typically use burn-in software or special burn-in music.

However, using burn-in software without having any professional background in doing so or expert guidance to help will most likely result in a good pair of earphones burning out. Excessive current values (volume), excessive burn-in time and monotonous, repetitive sounds can all contribute in overheating and the deformation of the voice coils and/or breaking of the diaphragms, causing the earphones to produce crackling sounds and this unfortunately, cannot be fixed.

Observing Chord&Major earphones as an example, the use of burn-in software is not recommended. In order to fully open up the diaphragm elasticity, all is needed is a diverse range of music. We also recommend progressive music styles, from light to heavy, and from slow to fast, similar to the exercise principle of warming up prior to running.

(3) Sound volume:

The volume level used for the burn-in process is based on the sound player’s volume. The basic principle for burn-in volume is from low to high. When the volume is high, the burn-in time should be shortened; regular breaks are a must. It should be noted that earphones should not be used during the burn-in process, especially when the sound volume is high as this can impair hearing.