Does Equipment Break In, or Does Our Hearing Adjust?

I have experienced and struggled with break-in of audio components for fifty years. It is a pain in the butt… especially when upgrading. Typically high quality components take 600 hours… although the largest portion is done by ~ 200 hours. Typically I don’t hear much change in wires beyond 200 hours, but if I move them in a big way or take them out for a long time and they will need ten or twenty hours to settle down.

All this is completely reproducible and easy to detect for the experienced listener.

I had the experience of breaking in three identical Audio Research Reference 160s amplifiers. I was absolutely amazed at how each followed exactly the same very complicated change in sound. In particular in the 120 hour range after the amps sounded better than at the start, would suddenly sound terrible for a session, then great, then terrible. This flip flop lasted for around 20 hours.

The mind becomes more sensitive to a component at the beginning as you subconscious becomes aware of the sound characteristics. It does’t perceive the sound differently, it becomes able to sense deeper into the nuance.

The Audio Research Reference 5SE preamp required about ten minutes of actual music playing through it each time before it sounded right, even if it had been warmed up for an hour. I thought there was something was wrong with my head. It was absolutely repeatable. I went to a audiophile forum where all the users own high end audio systems (Audio Afficianado) only to find a number of users discussing this peculiarity. The newer Audio Research Reference 6SE does not do this. In fact it needs little warm up to sound perfect.

Anyway, for the experienced audiophile these changes are easy to hear and must be taken into account when creating, upgrading or changing your system. There is no controversy on this subject among audiophiles.

@ghdprentice

I had the experience of breaking in three identical Audio Research Reference 160s amplifiers.

Great amps. How did you happen to have three 160s?  Did you buy the 160 stereo version and then decided to buy the monos, or vice versa?

Agreeing with what other have said here, it is true that for some of us at least it’s our ears that do the vast majority of the breaking in. I’ve bought identical amps new and listened to them both at the start, and judged them to sound identical - equally bad. Then burned one in for a few hundred hours and noticed it sounding dramatically better. Comparing them again at the end of the burn-in I discovered to my delight that they still both sounded the same but dramatically better than they did at the beginning. I’m not going to insist that some people may not notice real equipment changes over time. But it is fascinating that the burn-in almost always seems to improve the sound rather than degrade it. You’d think there’d be occasional components that go the wrong way. Or perhaps reach their peak sound quality mid-way through the burn in but then slide back a little before stabilizing. Also it seems rare for equipment to brighten its sound signature as it breaks in.

One way to know for sure with your sound bar would be to do before and after measurements. The apparent tonality change should readily show up on a frequency response graph if it was actually caused by physical changes in the sound bar’s performance. Or another option is to go buy another one just like it that’s new in the box and see if it sound bright and tinny.

Now that I think about it there are other possibilities besides just burn-in. Some components could conceivably change sound quality for better or worse over time whether used or not. Some could conceivably sound better after a burn in period, but then lose the burn in effect if not used regularly enough so that another burn in period is required. Some could even start to degrade from excess use but then recover if left unused for a period of time. These all sound like nightmare scenarios to me. I’m glad that the changes most equipment go through due to burn-in have negligible effect on my enjoyment of music. My ears are not hyper discerning so there’s a lot of serviceable equipment that seems stable over long periods of time to my perceptions.