Hi-Fi Myths and Legends

Breaking/running-in is one of the silly aspects of audio - led by the faith-based brigade.  If you think you will hear something, you probably will, and no argument can change that.  The mind is a marvellous instrument.

It is discussed briefly on p. 353 of Floyd Toole's excellent book " Sound Reproduction":

Breaking in.
In parts of the audio industry there is a belief that all components from wires, through electronics, to loudspeakers, need to “break in”. Out of the box, it is assumed that they will not be performing at their best. Proponents vehemently deny that this process has anything to do with adaptation, writing extensively about changes in performance that they claim are easily audible in several aspects of device performance. Yet, the author is not aware of any controlled test in which any consequential audible differences were found, even in loudspeakers, where there would seem to be some opportunities for material changes. A few years ago, to satisfy a determined marketing person, the research group performed a test using samples of a loudspeaker that was claimed to benefit from “breaking in”. Measurements before and after the recommended break in showed no differences in frequency response, except a very tiny change around 30-40 Hz, in the one area where break-in effects could be expected – woofer compliance. Careful listening tests revealed no audible differences. None of this was surprising to the engineering staff. It is not clear that the marketing person was satisfied by the finding. To all of us this has to be very reassuring because it means that the performance of loudspeakers is stable, except for the known small change in woofer compliance caused by exercising the suspension, and the deterioration – breaking down - of foam surrounds and some diaphragm materials with time, moisture and atmospheric pollutants. It is fascinating to note that “breaking in” seems always to result in an improvement in performance. Why? Do all mechanical and electrical devices and materials acquire a musical aptitude that is missing in their virgin state? Why is it never reversed, getting worse with use? The reality is that engineers seek out materials, components and construction methods that do not change with time. Suppose that the sound did improve over time as something broke in. But, what then? Would it eventually decline, just as wine goes “over the hill”? One can imagine an advertisement for a vintage loudspeaker: “An audiophile dream. Model XX, manufactured 2004, broken in with Mozart, Schubert and acoustic jazz. Has never played anything more aggressive than The Beetles. Originally $1700/pr. Now at their performance peak, a steal at $3200.”

Thanks to Dr. Floyd E. Toole for his kind permission to reproduce this article.