[Prog Rock Man]

Quote:

Wavecor driver specs have values for both pre and post burn-in... but the sceptics are probably going to ignore it anyway.
 
http://www.wavecor.com/html/wf152bd03_04.html

There are regular sceptics here who are persuaded by the evidence that there does appear to be something valid with regards to speaker burn in.
 
Two questions about Wavecor's measurements
 
1 - are the differences audible?
 
2 - will the speaker go back to its pre burn in state if rested?
 

 

[Adda]

Quote:

There are regular sceptics here who are persuaded by the evidence that there does appear to be something valid with regards to speaker burn in.
 
Two questions about Wavecor's measurements
 
1 - are the differences audible?
 
2 - will the speaker go back to its pre burn in state if rested?
 

1. The changes will make a difference, these drivers are for DIY projects, the mechanical specs of the drivers dictate how the speaker chassis has to be designed (bass reflex, backhorns and so on).
If the chassis is not designed very accurately the speaker will not be accurate, if you doubt this, then read up on speaker design, the more you read, the more you'll realize just how complicated speaker design is.
 
2. Who knows, but according to Weavecor they do change with use, my own bass speakers do not return to a pre burn-in state if not used for weeks, as for months or years, I don't know.
 
Notice that the changes Weavecor shows have to do with the mechanics of the driver, that makes sense as pretty much all mechanical devices change with use, and because the mechanical specs are extremely important in relation to chassis design.
 
When I replaced the GAMMA BK-3013a bass woofers in my speakers with Skytronic 902.222 woofers I learned that burn-in does happen for sure, at least with some drivers.
At first they sounded suppressed and compressed, they also had lower sensitivity then they do now almost one year after they got installed.
During the first 12-24 hours they loosened up and became more open, light sounding and sensitive, especially the sensitivity is easy to hear as they have to play together with two other drivers, comparing sensitivity between them is easy.
I also learned how important proper chassis design is, the bass reflex in my speakers is not tuned for these basses, so even though their specs are very close (within the Weavecor pre/post burn-in changes) the bass has a HUGE hump between 64 and 78 Hz.
With the GAMMA basses they did not have this problem at all, if I cover up the reflex tubes, the hump disappears, but the bass woofers sensitivity drops too low.

 

[Argo Duck]

The cost. Clutz sketched a plausible study design, and his/her estimates of sample size sound feasible, albeit we don't have any effect-size estimates to rest the calculations on. So lets accept (IIRC) 500-1500 audiophiles needed for this study...there's the problem. The time and cost of such a study is huge.
 
Unless someone is bravely testing a new area, precious research time and funds usually get committed to advancing domains with an established literature and at least the makings of a theory to test.
 
That, and I guess the fact audiophiles are a minority group, is highly limiting for what kind of real science gets done relevant to our (head-fi) interests, IMHO.
 
What frustrates me is it leaves most of what we say - on all sides of these debates - untestable, incapable of resolution, and hence just talk. 
 
Quote:

Scientists do do some weired and odd research
 
http://en.wikipedia.org/wiki/Ig_Nobel_Prize
 
I am surprised that audiophile claims have not attracted much interest.

 

 

[swbf2cheater]

This debate seems unwinnable and eerily similar to the Superman vs goku debates that riddle the sci fi and movie forums.

Zomggggg goku wins cuz he gots teh' Kamehameha!!!

Why can't you guys chill out, sit back, relax and just enjoy your gear and music without some unimportant technical debate. Who cares if it really exists, my headphones sound great!

 

[kingpage]

Kamehameha? That won't hurt superman enough. Goku wins because he can go super-saiyan 5, and also he can come back to life with the dragon ball even if he's dead; whereas when superman dies, he dies forever. (Technically, he can die. His parents did.)

 

[swbf2cheater]

Well, my point was that the debate is pretty dumb to me.  Just enjoy what you have, if anyone thinks sound changes over time then let them think it.  Who cares?  The idea that burn in makes the gear sound better over time is a good thing, why fight the idea?  There are more than likely a ton of factors that could contribute.  Why stress over it?  I trust guys like Tyll over the majority here anyway so his word is enough for me to be happy with.  My ears don't lie  ( at least I hope they don't ) I hear subtle changes over a short period of time, usually within 24 hours of normal usage.  I've never heard anything "open up" beyond that point.  I trust my ears, not what a machine that doesn't currently exist to test this theory might say.
 
 
 

 

[liamstrain]

Does the truth matter? 
 
To me, it does. I'm fine with "I don't know" or "results are inconclusive" or even "many people believe this" - but to actively, and repeatedly state as fact, something which is NOT a fact... bothers me on a very fundamental level - even if there is no actual harm from the misrepresentation. Hard for me to explain why - I guess I have a low tolerance for BS.   
 
 

 

[Prog Rock Man]

There is too much pseudoscience and belief in myth in hifi and I think it is worthwhile studying the subject with a more scientific evidence based approach.

 

[Argo Duck]

I have sympathy with all three of these views believe it or not.
 
Ideally, we would indeed establish some good science. It's possible, and will happen eventually. Positions currently contentious could be decided and new breakthroughs made. Btw, I suspect it might bring surprises to all sides - if only because I find research often produces surprises. Hypotheses and predictions based on solid and well-established theory and previous findings are refuted, and unexpected new directions are opened.
 
As far as head-fi is concerned, there are many good postings on the science side of things; liamstrain and Prog Rock Man are among the contributors. OTOH, there was also quality discussion in one of the threads concerning Tyll's 'burn-in' results, between UpStateGuy, Head Injury, and with really interesting, informed contributions from BlackbeardBen. Just as my appetite was getting whetted, the problem of doing worthwhile research became evident. Essentially, this is a talk group. Science rests finally on experiment (theory-testing); application of theory without this final testing is conjecture.
 
I pondered the idea of a 'collaboratory' - an internet collaboration. However, whereas these succeed within formal science settings, in this case it would be informal. I've seen people try these before. They've failed, even when cost has not been the issue it is here.
 
Hence, and purely pragmatically, I - just me, this is not a view I advocate for others - come back to swbf2's position.
 
Not permanently. But for now.

This debate seems unwinnable and eerily similar to the Superman vs goku debates that riddle the sci fi and movie forums.
Zomggggg goku wins cuz he gots teh' Kamehameha!!!
Why can't you guys chill out, sit back, relax and just enjoy your gear and music without some unimportant technical debate. Who cares if it really exists, my headphones sound great!

Does the truth matter? 
 
To me, it does. I'm fine with "I don't know" or "results are inconclusive" or even "many people believe this" - but to actively, and repeatedly state as fact, something which is NOT a fact... bothers me on a very fundamental level - even if there is no actual harm from the misrepresentation. Hard for me to explain why - I guess I have a low tolerance for BS.   

 

There is too much pseudoscience and belief in myth in hifi and I think it is worthwhile studying the subject with a more scientific evidence based approach.

 

 

[sailorman]

 
Quote:

Your logic is sound except it isn't logical in academia. I may not have been in the research area for a long time, but I have been to countless of seminars, discussions and so on and have seen and talked to many professors and researchers in my discipline as well as others, nevermind fellow students. At least in university, academic researchers don't see profits or the dollor sign when they decide what or how they approach their area of interests. The ones who do care about money get filtered out either early or they eventually leave academia after getting the qualification or some experience to gain an advantage in employment outside. The ones who stay behind for all those years, will always put their interests and ability above everything else.
 
What I'm saying is that we may never find a well-excercuted study to be conducted by independent scientists such as at universities or research institues on the existence or different effects of burn-in in headphones. Like you said, driven by profits and other monetary incentives, people who work closely with the headphone industry or are in it are much more likely to conduct research in this particular area. In many senses, it is also hard to accept those results even when it's done right because of conflict of interests and their own vested interests.
 
One day, someone may come along, and have lots of grant money and and an interest in this and doesn't care about returns but want to see results. Let's hope that person comes sooner than later, not fall before all the potential "distractions and attractions" that lure him away from this.

Sorry, but this shows you have a fundamental misunderstanding of science and the scientific method.  If the science is done properly, it would be repeatable and verifiable and peer-reviewed. Thus, the initial researcher's connection to industry would be rendered a moot point.  The nature of the scientific method is such that biases in the pursuit of profit are discovered, exposed and/or eliminated.  If the science supports burn-in as a legitimate phenomenon, it ill be accepted regardless of any perceived conflict of interest or vested interest.
 
FTR, Subjectively, I think that in some cases burn-in has an effect. I also know that I've seen no credible science to back it up and, therefore, I'm willing to attribute my perception of those changes to placebo.

 

[Head Injury]

Quote:

I pondered the idea of a 'collaboratory' - an internet collaboration. However, whereas these succeed within formal science settings, in this case it would be informal. I've seen people try these before. They've failed, even when cost has not been the issue it is here.

You mean something like have a lot of Head-fiers independently measure their new headphones for differences over time? That would be difficult or impossible. Headphones are very tricky to measure properly, because you're working with real sound waves and not pure electricity like in amps. Sound waves are subject to changes in headphone placement (placement relative to mic, pad burn in), interactions with external sounds, the type of mic itself, even atmospheric conditions to some degree (though that's probably negligible for headphones). Everyone's measurements are going to be different, and there's no good way to make sure everyone's results are repeatable. You'll get a lot of data, but most of it will be unverifiable.

 

[swbf2cheater]

Quote:

 


Sorry, but this shows you have a fundamental misunderstanding of science and the scientific method.  If the science is done properly, it would be repeatable and verifiable and peer-reviewed. Thus, the initial researcher's connection to industry would be rendered a moot point.  The nature of the scientific method is such that biases in the pursuit of profit are discovered, exposed and/or eliminated.  If the science supports burn-in as a legitimate phenomenon, it ill be accepted regardless of any perceived conflict of interest or vested interest.
 
FTR, Subjectively, I think that in some cases burn-in has an effect. I also know that I've seen no credible science to back it up and, therefore, I'm willing to attribute my perception of those changes to placebo.

 

 
 

 

[castleofargh]

i don't see how difficult it is to go low-fi pro on this one. can't anyone getting some new headphone go and badly ducktape the son of a wire onto a microphone for a few days? then record whatever the mic can get, do some burn in practice and record the same thing a few times along the process. if you don't live in front of an airport, under a highway, next to the suburb we can imagine the possibility of somehow conclusive side by side comparison in whatever audacity software.
that is a poor way of going at it but it sounds to me like a way where our brains and superman lovin issues don't mess with the results.

 

[Head Injury]

Quote:

i don't see how difficult it is to go low-fi pro on this one. can't anyone getting some new headphone go and badly ducktape the son of a wire onto a microphone for a few days? then record whatever the mic can get, do some burn in practice and record the same thing a few times along the process. if you don't live in front of an airport, under a highway, next to the suburb we can imagine the possibility of somehow conclusive side by side comparison in whatever audacity software.
that is a poor way of going at it but it sounds to me like a way where our brains and superman lovin issues don't mess with the results.

 
If you want conclusive results, you won't find them in a test with so many unchecked variables and such a small sample size. All a test like that would accomplish is provide misleading fodder to one camp or another.
 
If we want data, we need it to be repeatable and careful like Tyll's data. Then we need blind tests after that, as hard as they are for headphones, too.

 

[Argo Duck]

Yes you state the objections exactly. This, or something like it, is what I pondered. And this is what I meant by cost - to ensure training, re-calibrate constantly, get inter-rater data to check on listener drift etc let alone the hp measurement issues you identify. Heck, I've seen lone experimenters screw up their data frequently, and what they were doing was simple.
 
Beyond this, I thought of something else. Bringing together the expertise in the fields needed to address these questions. They are a multi-disciplinary problem scientifically speaking. We seem to have the skills needed on head fI. However, I don't know we could get this to work either.
Quote:

You mean something like have a lot of Head-fiers independently measure their new headphones for differences over time? That would be difficult or impossible. Headphones are very tricky to measure properly, because you're working with real sound waves and not pure electricity like in amps. Sound waves are subject to changes in headphone placement (placement relative to mic, pad burn in), interactions with external sounds, the type of mic itself, even atmospheric conditions to some degree (though that's probably negligible for headphones). Everyone's measurements are going to be different, and there's no good way to make sure everyone's results are repeatable. You'll get a lot of data, but most of it will be unverifiable.