[Wayner]

Danny, I was being "hypothetical" in my first post. The fact is I think this thread is talking about 2 different issues, unless I read wrong. The words "burn-in" and "break-in" ,IMHO, can't be interchanged, as they are 2 different things. Burn in is a theory I just can't buy into. Break in, I can.

Wayner

[jackman]

Hey, I'm a fan of Dennis and Danny's work and respect both guys.  It's cool to have a difference of opinion and this thread has been civil, as I expected it to be. 

For me, I'm not sure I buy into speaker break-in because in my experience I don't recall any of my speakers sounding noticeably better or different after 5 or 10 hours of heavy playing.  This doesn't proove anything and is by no means meant qualify as scientific proof of anything. 

Lastly, there was a time when I was "certain" all amps sounded alike, and that speaker cables, PC's and IC's didn't make a difference.  Over time, I have changed this belief and I am confident cables can make a positive contribution to a system.  Maybe someday I'll realize the same thing about break-in.

Cheers,

J

[charmerci]

My belief is that it is 'hearing break-in" - i.e. the more you listen, the more subltities that you are recognizing.

Take modern painting as an equivalent. Most people will initially look at a piece and say "That's awful" or "Any kid could do that." But after years and years of studying you begin to see what the intention of the artist is and other rules that they are (or even aren't) following.

The more you listen, the more you hear.

[Paul K.]

I agree.  While Danny refuses to acknowledge that his measurements clearly show very little change in the three parameters, in most cases, between 1 hour and 80 hours, which really is the whole point AFAIC, that's not going to change his belief that there isn't a change in sound, nor is it going to change my belief that there is or can be.  So, close the thread.
Paul

But in every subjective listening test the speakers sound better after break in (), which right there is a big 'ol red flag.

This thread has remained very civil, so I don't think it needs to be closed on account of behavior.  However, nothing will change.  Danny will always state drivers do break in and the difference is audible, and the rest of us will believe that the any measured change is below the audible threshold.  No one's opinion will change, and nothing will get accomplished.  In short, this will be a complete waste of time, and that in itself is why closing the thread isn't such a bad idea.

[JP78]

Danny will always state drivers do break in and the difference is audible, and the rest of us will believe that the any measured change is below the audible threshold. 

I don't think it's fair to pit Danny against everybody else in this forum. I definitely believe in break-in...several years ago I remember having to readjust the PRs on my VMPS after I had played them for a couple weeks.

[Dyne Analytics]

Well, this is certainly a "spirited" discussion, so here's my $0.02!  Spiders take a long time to break in and constantly are changing.  While the majority of the break in occurs in the first hours, the fibers continue to fatigue and break; to what degree is another discussion. There is also a"Stability of Shape" which measures a spiders deformation over a long period (think subwoofer mounted with the axis vertical and the moving mass of 250 grams).  Spiders also change drastically with changes in temperature, humidity, and excursion.  The last is not widely known but large excursions "untangle" the fibers.  Upon rest, the fibers sort of re-entangle (is that a word?).  And to confuse it more, there's cotton, acyrlic, polyether-cotton, bimax, bimax sandwich, conex, nomex and others all reacting differently to temp, moisture, shape stability, etc.

A typically spider cost about $0.09; this means spiders are a commodity.  And commodities leave no profit left for R&D.  A "cheap" but good spider tester is $10k (True Technologies).  Dr. Kurt Muller has done a little testing but all static hysteresis.  Wolgang Klippel et al have done quite a bit but their instumentation starts at $30k or so.  There is a need for research and our company, DYNE Analytics, is considering submitting a research paper for ALMA International's WInter Symposium in 2013; all we need is a lot of time and a lot of money! 

So, I guess I am saying that spiders change in the short run (a single large excursion) and the long run.   

[Danny Richie]

I agree.  While Danny refuses to acknowledge that his measurements clearly show very little change in the three parameters, in most cases, between 1 hour and 80 hours, which really is the whole point AFAIC, that's not going to change his belief that there isn't a change in sound, nor is it going to change my belief that there is or can be.  So, close the thread.
Paul

The "little" change showed a Fs drop between 6 and 10%. Vas increased between 6 and 30%, and Qts figures decrease by 5 to 10%. That is not "little" change.

And changes in decay rates are easily equated to audible differences. It is an acoustic measurement made with a microphone. It verifies the audible change.

Now whether you hear the changes or not is up to you. You may or may not notice a change. I never knock anyone for saying they hear no difference. I believe them. But one cannot conclude that because they hear no change that there is no change. It only means "they" hear no change.

Another thing to note is that with a lot of budget level or mid-fi level receivers, CD players, etc, it will not be as easy to hear the differences.

[Danny Richie]

Danny, I was being "hypothetical" in my first post. The fact is I think this thread is talking about 2 different issues, unless I read wrong. The words "burn-in" and "break-in" ,IMHO, can't be interchanged, as they are 2 different things. Burn in is a theory I just can't buy into. Break in, I can.

Wayner

Burn in and break in are terms used synonymous with one another.

Sounds like you are trying to separate mechanical and electrical effects. Or maybe you are trying to separate the objective from the subjective.   

[Danny Richie]

Hey Dyne, welcome to AC and thanks for contributing.

[Saturn94]

Hey, I'm a fan of Dennis and Danny's work and respect both guys.  It's cool to have a difference of opinion and this thread has been civil, as I expected it to be. 

For me, I'm not sure I buy into speaker break-in because in my experience I don't recall any of my speakers sounding noticeably better or different after 5 or 10 hours of heavy playing.  This doesn't proove anything and is by no means meant qualify as scientific proof of anything......... 


Cheers,

J

+1

I find it interesting that although Dennis and Danny are on opposite ends of the spectrum on some things, they both end up designing excellent sounding speakers.

[jtwrace]

Well, this is certainly a "spirited" discussion, so here's my $0.02!  Spiders take a long time to break in and constantly are changing.  While the majority of the break in occurs in the first hours, the fibers continue to fatigue and break; to what degree is another discussion. There is also a"Stability of Shape" which measures a spiders deformation over a long period (think subwoofer mounted with the axis vertical and the moving mass of 250 grams).  Spiders also change drastically with changes in temperature, humidity, and excursion.  The last is not widely known but large excursions "untangle" the fibers.  Upon rest, the fibers sort of re-entangle (is that a word?).  And to confuse it more, there's cotton, acyrlic, polyether-cotton, bimax, bimax sandwich, conex, nomex and others all reacting differently to temp, moisture, shape stability, etc.

A typically spider cost about $0.09; this means spiders are a commodity.  And commodities leave no profit left for R&D.  A "cheap" but good spider tester is $10k (True Technologies).  Dr. Kurt Muller has done a little testing but all static hysteresis.  Wolgang Klippel et al have done quite a bit but their instumentation starts at $30k or so.  There is a need for research and our company, DYNE Analytics, is considering submitting a research paper for ALMA International's WInter Symposium in 2013; all we need is a lot of time and a lot of money! 

So, I guess I am saying that spiders change in the short run (a single large excursion) and the long run.

Welcome to AC.    

Is this you?  http://www.dyneanalytics.com/p1.htm

[Dyne Analytics]

Yes, that is us.  We are releasing a new driver design tool which predicts cone, dome, dust cap, surround, and spider behavior.  Thus the reason I have been looking into DYNAMIC behavior/testing of spiders (not static!).  It's a lot tougher than you think.  There are large variances on acceptable spiders. To be honest, i find it amazing that two identical speakers even sound similar with all the variances in materials and labor.  Just one drop of glue running out into the spider drastically changes everything.

But, I digress.  In order to discuss the original topic, get out of the frequency domain and think in the time domain.  While FR is a steady state response, Mr. Richey is talking waterfall: that is time domain (actually a hybrid of the time and FR).  Two drivers with identical steady state FR can behave totally different in the time domain.  But, now we are starting to get into linear and non-linear damping.  Egads!!!!

[Paul K.]

It sure is convenient how you list only the larger changes.  From the first link to your tests you show the burn-in changes results for 8 drivers, and just focusing on Fs, the range of change between 1 hour and 80 hours was 2.2% to 9.6%, with four of drivers changing 3.3% or less.  The driver with the most change was one of "yours". I'm sure I can find similar smaller changes than you are acknowledging in Qts and Vas, but I'm done with this topic.
Paul

The "little" change showed a Fs drop between 6 and 10%. Vas increased between 6 and 30%, and Qts figures decrease by 5 to 10%. That is not "little" change.

And changes in decay rates are easily equated to audible differences. It is an acoustic measurement made with a microphone. It verifies the audible change.

Now whether you hear the changes or not is up to you. You may or may not notice a change. I never knock anyone for saying they hear no difference. I believe them. But one cannot conclude that because they hear no change that there is no change. It only means "they" hear no change.

Another thing to note is that with a lot of budget level or mid-fi level receivers, CD players, etc, it will not be as easy to hear the differences.

[Danny Richie]

It sure is convenient how you list only the larger changes.  From the first link to your tests you show the burn-in changes results for 8 drivers, and just focusing on Fs, the range of change between 1 hour and 80 hours was 2.2% to 9.6%, with four of drivers changing 3.3% or less.  The driver with the most change was one of "yours". I'm sure I can find similar smaller changes than you are acknowledging in Qts and Vas, but I'm done with this topic.
Paul

Better check your math Paul. Going down the list Fs changes are 5.4%, 9%, 4.4%, 7%, 7.8%, 9.4%, 4.6%, and 20%.

On the driver with a 20% it was noted:

The M-165X woofer was fresh out of the box that was from our storage area. It was quite a bit colder than the temperature in the measuring room and caused the greatest amount of change in initial measurements compared to the other drivers. The colder temperature causes the Fs to be higher, Vas to be lower, and Qts to be higher.

It was probably 30degrees colder than room temperature when testing started. It clearly shows temperature having a big effect.

A quote from another driver designer:

Danny,

You're spot on with the mechanical changes. The biggest reason there is a break-in period for drivers is the spider. The spider - for those who don't know - is a piece of cloth, permanent pressed, and dipped in epoxy. When you break in a driver, you introduce micro-cracks throughout the epoxy, which will make the spider softer.

ALL mechanical systems will wear and all mechanical springs will get softer; in this case, it's by design. You break/crack a lot of the epoxy bonds (phenolics are used as well) that permeate the spider, and thus it becomes softer.

We often see a 20% drop in Fs over a lengthy break-in, and we quote numbers for drivers broken in. Out of the box all our drivers measure high; beat on them for 40-50 hours, though, and they will be permanently lowered (Fs, that is).

One thing to note is that it would be expected Fs would drop, Qes and Qts would drop, and Vas would increase; all these are exactly what happens when you raise Cms, which is the same thing as making the spider softer.

Dan Wiggins 7-14-06

[Paul K.]

You better check your math and read my posts more carefully first.  Between the 1-hour and 80-hour numbers you listed for Fs, the changes were: 2.5% (33.61 to 32.74), 7.2% (54.41 to 50.47), 3.2% (44.41 to 43.01), 3.3% (53.00 to 51.24), 5.5% (65.44 to 61.84), 6.2% (43.91 to 41.19), 2.2% (48.06 to 46.98) and 9.6% (39.81 to 35.97).  You appear to using the fresh-out-of- the-box values or those after a 1-minute burn-in as your baseline, but I was giving you the benefit of the doubt by recognizing there is some break-in that will cause permanent changes and, therefore, used the 1-hour numbers as my baseline.  Also in my first reply I said most of the changes were in the 2 to 6% range, which were based on scanning the numbers and mentally calculating the per cent change. As it turns out for Fs, 6 of the 8 drivers showed a change of 2.2 to 6.2%.  So, yes, there are changes due to break-in of drivers, but the changes on the whole are not significant and no more than, even less than the potential "errors" due to tolerances of capacitors and inductors used in the crossover.  An hour of burn-in is completely adequate.
Paul

Better check your math Paul. Going down the list Fs changes are 5.4%, 9%, 4.4%, 7%, 7.8%, 9.4%, 4.6%, and 20%.

On the driver with a 20% it was noted:

The M-165X woofer was fresh out of the box that was from our storage area. It was quite a bit colder than the temperature in the measuring room and caused the greatest amount of change in initial measurements compared to the other drivers. The colder temperature causes the Fs to be higher, Vas to be lower, and Qts to be higher.

It was probably 30degrees colder than room temperature when testing started. It clearly shows temperature having a big effect.

A quote from another driver designer:

[Danny Richie]

Okay Paul,

So we both know how to do math. You were just moving the base line over one hour. I get you now.

Burning a woofer in works like this. Let's say you are moving from point A (fresh woofer) to point B (no more compliance change). After about 5 hours of hard play you get about half way there. Double the amount of time (about 10 hours) and you move about half way again. Double that amount of time (about 20 hours) and you move half way there again. Each time longer and longer amounts of time are used but the total distance moved is less. Pretty soon you call them settled as the temperature rise from playing them begins to move them more than the added time.

So I guess any time in your subjective view that you want to call the change "little" is up to you. There is no arguing over a subjective evaluation of how great the changes are. That's like arguing over how dark it is outside. It's not very dark, oh yeah, it's pretty dark....

[Wayner]

I was once told during my engineering skooling days that everything that man creates, including himself, begins to break down. We build houses, they soon fall apart. We build cars and soon they rust, quit running and fall apart. We get middle aged and our hearing, sight and hair start to get lost.

Everything man makes starts to fall apart the second man makes them. It's an unholy bond between alloys or materials that start the molecular revolution and it continues until the dismantling process is complete.

So, I then ask, is break in only part of the process of break down. Is burn in (in electrical terms) just the beginning of burn out. Is wear in the beginning of wear out.

Where do tolerances come into play? If we have a shaft that is too large to fit into a hole that is too small, we don't have assembly. If we have a shaft that is too small in a hole too large, we have behavior problems and wear.

The other question is how does wear or break in or burn in know when to stop? Who said that when something breaks in, that it's a good a thing. I broke in my new jeans but soon they had holes in them. So the break in process was part of the break down process.

W

[audiotom]

wayne

I look at it more like a person that learns how to relax

it's a good thing

[DMurphy]

This discussion is getting a little metaphysical.  Although Danny and I probably do disagree on the practical significance of break in, I don't think the disagreement itself has much practical significance.  I can see where box tuning might be affected by meaurements taken after 10 seconds of woofer play vs 100 hours, but I don't think the crossover  design will be.  That's something you can check easily--just measure the frequency response and phase tracking of a given speaker repeatedly over a period of time.  When I've done this (and the speaker used one of Danny's woofers), I sure couldn't see any difference.  So I would have come up with the same crossover no matter where the woofer was in its real or imagined break in period.  I guess you can spin a tale about cone midrange response curves changing at the low end over time and therefore impacting the woofer-mid cross in a 3-way, but again I haven't observed that.  So maybe I'm wrong about the audibility of break in.  Could be.  But I don't think it would affect my crossovers. 

[Æ]

The other question is how does wear or break in or burn in know when to stop? Who said that when something breaks in, that it's a good a thing. I broke in my new jeans but soon they had holes in them. So the break in process was part of the break down process.

It stops when it fails, when it is worn out. I just hate it when a pair of jeans or shoes or whatever is really comfortable, then unfortunately it is time to replace it.

If you ever have a good "broken in" woofer and you stop using it, box it up, put it away for a while, it reverts back (mostly) to its former stiffness.