Burn-In: real or imagined? A proposed experiment.

[Arkay]

I've been thinking about the discussions and arguments that periodically have arisen over whether gear actually changes with "burn in", or whether our ears (brains) just adjust to sonic changes, instead.

My "sneaking suspicion" suggests that in all probability, BOTH things do happen, to varying degrees. But "Arkay's Sneaking Suspicion" (ASS for short ), for some unfathomable reason, is yet to be generally accepted as universal truth, and modesty (plus concern for the welfare of others) prohibits me from suggesting my ASS be paraded around as a universal standard ().

Which leads to the question... Has anyone ever made a careful, high-quality tape recording before burn-in, and then after a suitable burn-in period has elapsed, and without altering anything in the recording set-up at all, taped the same material afterward, and then played back the tape, listening for differences?

While not a perfect experiment (because of variables like the warmed-up temperature of the tape deck, etc...), I would think it to be a much more valid proof of the existence or non-existence of burn-in changes in a given instance. Our PERCEPTIONS change much more than the physics of a single strip of tape, unmoved in a single recorder, with the same unmoved microphone, etc..., especially when the two recorded performances can now be repeatedly played-back, one immediately after the other.

Take a new cartridge that is reputed to require burn-in, or something more controversial, such as new speakers. Record a song, and stop the tape. Let the thing burn in for sufficient hours, then start the same song, and record it again, starting the tape right where it had been stopped. Rewind and play back the tape, and listen for differences. Presumably, most differences could be attributed to burn-in.

Set up the experiment to control along the way, as well as you can, for variables like tube gear being warmer (perhaps let it all cool off before making each recorded version, or bring it up to similar temperature after similar warm-up times before making each recording, or use all solid-state gear.

Anyone done this?

Any takers with new (not yet "burned in") gear and good recording gear, willing and able to try it?

Perhaps sound files of the results could be uploaded somewhere, for all to hear and judge for themselves what changes occurred (or didn't). It might help settle the question, at least for some gear and for some people.

I will try to do this the next time I have something new, but almost everything I buy is old, vintage stuff, so I don't know when it may be. Vintage stuff, I always assume, is way past any "burn in" period. So I thought I'd pass the idea along, in case anyone else might want to try this.

[whoaru99]

To me it's too potentially fraught with expectational biases from either/both camps. IMO, this sort of thing needs to be a DBT- or ABX-type of experiment.

[Andyman]

To me, it's way too many variables and way too subjective.

Intuitively, it makes sense as we know many devices, ourselves included, need warms ups to get going, which is essentially the same function as burning in. But to make a serious attempt to quantify it would be very daunting.

[fiddlefye]

It would be interesting, but I'm not sure how much it really matters in the long run. There will always be two camps on this one regardless of what experiments are done. I know that I'm quite convinced of changes occurring as I've heard it happen a bit too dramatically a couple of times with my own gear. The one that really did it for me was my C-4 pre-amp after it had been re-done. I had my tube CJ PV 12 pre in the system, took it out and put in the C-4. I found it painfully bright, edgey and with a tonal balance out of whack, funny mid-range hump and if it weren't for the fact that the C-4 has a fine rep I'd probably have pulled it again and sold it. I hung in there and after a couple of weeks of hard use that all vanished and sweetness reigned. When I put the CJ back in again the difference was negligible in any of the aspects I had heard before, same when I put the C-4 back in this Summer. The differences I heard were a one-time thing and while there are some slight differences between the tube and SS pre they are amazingly small in all respects. After that experience I really had to stop being a sceptic. Just my experience, but it would have been interesting to have a record of what I heard to go back to afterward. Even a recording would be subjective, sure, but ultimately listening to music is a purely subjective experience. It constantly amazes me how much tiny differences in tonal balance (for example) can make or break the listening experience for me, at least in Classical music.

[SRVDean]

I THINK that speakers and catridges sound better after being played for many hours. I learned this from first hand experience after I replaced four woofers in some yamaha speakers, and a new cartidge on my turntable (these happened at different times though. After playing my yamahas after about a month, I noticed the bass was SLIGHTY deeper. I could hear a change, but not much. Same thing with my cartidge. It sounded good on day one, and still sound about the same way. I feel it has more bass, but I could be biased from changing out many speakers and amplifiers. I suggest a test. Buy two of the same tape deck, CDP, speakers etc.. (not expensive) right off the shelf. Play one for many hours, then get the other one out of the box, and do an AB test.

[donberry]

arkay - interesting experiment, but I am wondering - the 1st tape recorded would still be played back on the burned in amp, so if there were a difference, wouldn't that negate it ?
I would think the only way to actually test it would be if someone had 2 identical systems. Change the caps in one, play it for about a 100 hours and then change the caps in the other one - then compare.
Personally, and obviously just an opinion, I think it affects mainly film caps. Now I could have just been hearing things, but I put some obbligatos in a pair of speakers. At first I loved them, but as I got between 75-100 hours on them, I started noticing a boomy bass. I pretty much always have my tone controls on flat, but I found I was backing the bass off a click or 2. Swapped them back out, and now the tone controls are back to flat. Speaker position, source, amp and everything stayed the same - even tested it out on the same songs I am very familiar with as I really did not want to switch the caps back out. Could be something else,but I did perceive a difference. And again, I think it is more the film caps and not just the standard electrolytic caps. But I have been wrong many times before

[andy]

I think the only way to do this would be to have two identical components, have someone else burn one in, and then see if the first person can tell the difference (also see which one he prefers). It would probably be wise to compare them before the test to see that they both sound the same. Better yet, have 3 or more identical components, and see if he can pick out the one that was broken in. This would only work for things that don't have a great deal of variation between identical units, and that aren't complicated to setup the same way.

[OLDisGOLD]

I believe in a warmup period when eqiupment is 1st turned on, especially when it's in a cooler environment. I suppose there might be some subtle changes after a "break-in" period, with subtle being the keyword.

[Mark W.]

You could run the recorded tape on a diiferent system. Since you are looking tohear a change in the sound coming from the tape.

[Arkay]

I think some of you are missing my point, and completely misunderstanding what I am proposing. I'm not suggesting playing back ANYTHING on the equipment being tested, at the evaluation stage!

I'm suggesting using a tape-recorder set up to "take a sonic snapshot", so to speak, of what the gear in question is producing sonically, before burn-in. Then burn in the unit (completely apart from the tape recorder, which sits idle, off and untouched during the burn-in period).

Then take another "sonic snapshot" of what the gear in question is producing, AFTER it has been burned in, using the exact same, untouched tape recording. If the first "snapshot" test recording went from 0:00 on the test tape to 2:49, then the second recording could run from 2:50 to 4:49. The two "snapshots" would appear, one right after the other, on the same piece of tape, from the same machine, using the same microphone or connector cable (as appropriate), in the same room, with NOTHING altered except that the component in question had been given its "burn in time".

The tape deck is then used to play back the taped before-and-after "snapshot" samples, which appear one right after the other. One could use regular music and/or test tones or sweeps, etc... for source material, but the exact same source material is used for both tapings. Try to keep the taping set-up identical in both instances; control for and eliminate as many other variables as possible, by making the recordings at the same time of day, etc...

Once the tape is made, it can be played back anywhere, at any time: the results are based on the DIFFERENCES (if any) between the two recordings of the same source material, one made before burn-in, the other made after burn-in.

After the tape is completed, the gear being tested can be sent to the other side of the planet and it won't matter; it is NOT part of the playback or evaluation process. The person or people evaluating the tape for differences need not even know what the experiment is testing (to help eliminate bias): they simply listen to see if there are differences between the two adjacent recordings of the same material, and if there are, what the differences are. The test recordings could be put online, for others to judge for themselves.

Clear now?

[Arkay]

Originally Posted by Mark W.

You could run the recorded tape on a diiferent system. Since you are looking tohear a change in the sound coming from the tape.

Mark understood my intention correctly!


Of course, these days one might try to make the before-and-after recordings digital. I just like tape more, because I'm more used to working with it, and know how well it can capture sound, and think it is more fun, but I've done studio work with digital recording set-ups that were excellent, too. In fact, most (all?) studios here now are digital. The experiment would otherwise be the same.

[NAD C375BEE]

I think the "burn in" phenomena actually describes our brain getting used to the "differentness" of a new component relative to what it replaced. Once we get used to its differentness we can hear it withount the mental distraction of involuntary comparison it to what it replaced allowing us to enjoy it more...............my opinion of course.

[hypertone]

Oooh that's a nice avatar!

[jaymanaa]

Capacitors (especially high end ones) absolutely sound different after a burn in period. There is absolutely no doubt in my pea sized brain. When I first started hearing this, in home brew amps and crossovers, I figured it was my ears adjusting. To test that theory, I would listen to a new amp (once I got it sounding as good as possible) for maybe one CDs worth of music. Then I would put the player on repeat and turn the volume all the way down. What I experience regularly is a smoothing of the upper frequencies, and "fuller" lower end after around 50 or 60 hours. It was absolutely crazy on the first outboard DAC I bought.I bet it was more like 100 hours before it settled in and started sounding better than the built in CDP one.

[NAD C375BEE]

Originally Posted by hypertone

Oooh that's a nice avatar!

Yeah thats a nice stereo