QotD: What is Speaker Break-In or Burn-In?
You may have heard of speaker break-in or burn-in. This is the concept that a speaker needs to be used for a certain period of time in order to “sound right.” We’ve all experienced this with clothes. Shoes need to be worn for a while before they start to fit correctly. On the way to breaking-in, shoes may cause discomfort, pain, blisters, and more. You may find after wearing them for a while, that they are never going to fit correctly. Can that happen to speakers? Do speakers need a break-in period in order to sound right?
Explanation of the Speaker Break-In Rhetoric
The driver is the only thing within a speaker that could conceivably “break-in.” The drivers within the speaker are the only moving parts in the whole system. Within the drivers, there are very few actual moving parts. The two that could burn-in are the surround and the spider.
The surround is the foam part around the outside of the cone material. The job of the surround is to, mostly, keep dust out of the inside of the driver. The spider is the suspension of the driver. It keeps the voice coil centered both axially and front to back, within the gap of the magnet, and keeps it centered there. It essentially keeps the driver material so that, at rest, it is centered front to back and axially.
These two pieces are really the only parts that can be changed with movement. The force that moves the voice coil is magnetic and therefore can’t be changed by time and use. It can be broken by misuse, but the function shouldn’t change over time if the driver is used within tolerances.
The belief (as it has nothing to do with science) is that the suspension is rigid when it leaves the manufacturing line. It needs time to loosen up in order to get to its optimum performance range. The rule of thumb a speaker needs to play some sort of noise (white, pink, ZZ Top) for anywhere from 20 to 100 hours before they achieve “burn-in.”
There have been highly technical articles written on the topic, but let me simplify them for you. Any measurable changes to the surround and spider take less than a second to happen and don’t need to happen again. This means, the very first time the driver is used, there will be a slight loosening of the spider and surround. After that, it will not change. That is the speaker break-in that people are saying should happen. This means it happened long before they ever really started listening to their speakers.
Anecdotal Evidence that Speaker Break-In doesn’t Happen
There are a few things we can look at as proof that the only break-in or burn-in doesn’t happen at the speaker, it happens within the person. First, those that report burn-in often give a specific time period within which it happens. They report that after this period of time (sometimes weeks or months of playing white noise) the speaker somehow sounds different (usually better, often in the bass region). After that…nothing. No change.
So, what is happening here? Is the speaker really changing or is it something else?
Breaking in of the Ear
The process here is fairly simple to understand. The person (usually a reviewer) has a set of speakers in their system. They get in another set and find them somehow “off.” This is very likely attributable to the new speakers simply sounded different than their current speakers. Once they put them in “time out” for a while, suddenly, they sound better.
That difference in the timbre of the speakers can be a combination of many things. These types of reviews are usually made by audiophile publications that eschew room treatments, subwoofers, room correction, and other proven ways to optimize the sound in your room. Room acoustics, in particular, can have a massive effect on how a speaker sounds. So, when the reviewer gets a new speaker, they not only sound different by design, but the room is having a massive effect on how they sound.
Have you listened to the same song on two different systems in short order? Listened to a song on your computer speakers and then your headphones? Maybe your car and then in your house? Did they sound the same? Of course not! And that difference is usually perceived as “bad” at first. But, a few minutes later, you forget about the differences and just go back to enjoying the music.
This is speaker break-in. It happens at the reviewer’s head. Not at the speaker.
Does Speaker Break-In End?
Continuing this line of reasoning, if a speaker takes weeks or months to burn-in, does that process stop after that time period? Surely whatever is taking weeks to loosen up continues to stretch as the speaker is used? So why don’t we read any reviews about speakers that are “too” broken-in? Why don’t people with 20-year-old speakers complain that their speakers have become burned-in to the point that they are too bassy?
It doesn’t happen because the speaker wasn’t the place where the break-in happened.
Spend a moment thinking about how a speaker works, and you’ll realize that a driver that needs its suspension stretched is a terrible design. Drivers have to move in and out sometimes thousands of times a second. To continue to perform optimally, they need to operate within tolerances that would ensure that the movement would not change how the driver acts. That includes the rigidity of the suspension. It should not be pushed so far as to change or break-in. If it is, it could damage the suspension.
And then the speaker would truly be broken-in. And if you keep pushing, you’ll probably experience some burning as well.