Speaker Break-in Revisited - AVS Forum
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post #1 of 38 Old 05-01-2003, 05:49 PM - Thread Starter
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In a thread on Von Schweikert speakers, there was a recent exchange on the topic of speaker break-in. I know this one has been tossed around many times before and sometimes erupts into flamefests, but I thought it would be interesting to some to read what Albert Von Schweikert has written on this subject. So the next post is an excerpt from an article that Albert wrote in the recent past, which I pass along with his permission.

I will note that Albert does go further on tweater break-in than I would, so I'm not in total agreement with him. However I certainly highly respect his opinion and am willing to consider that he is more correct than I.

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post #2 of 38 Old 05-01-2003, 05:51 PM - Thread Starter
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"Break-in", Real or Imaginary?
by Albert Von Schweikert
Chief Design Engineer, VSA,
EgglestonWorks Audio, FPS Japan

Now let's move on to the hotly debated topic of speaker "break in." _The group of engineers "who don't [or can't)? hear differences" between components also believe that "audio break in" is a fallacy. _They cite the fact that "nothing" in the speaker cabinet can change after extended playing time, but I have measured extremely wide variances between Vas in the drive units themselves after 100 hours of playing time, leading to drastic sonic changes in the system. _Vas is an abbreviation for compliance, which can also be stated as how "loose" the suspension is. _Many audiophiles have pushed on woofer cones to see how far the cone can move, so they might have noticed that some woofers have very "floppy" suspensions as compared to some modern designs that are extremely tight. These differences in suspension compliance are not accidental, nor arbitrary. The tuning of a driver and enclosure is based on mechanical and electrical parameters named "Theile/Small Parameters," after the pair of math professors at the University of Sydney who quantified these measurements over 30 years ago.

These "parameters" are:

Fs = free air resonance of the moving assembly (the peak in the impedance curve showing the frequency at which the vibration is strongest).
Qms = the mechanical "Q" of the moving assembly (how strongly the cone or dome moves at its resonant point).
Qes = the electrical "Q" of the motor (the amount of electrical "braking" provided by the magnet on the voice coil movement).
Vas = the equivalent quantity of air that the suspension enables the cone to move (and is also a measurement of how "stiff" the suspension is).

The mechanical Qms and electrical Qes parameters are combined to give a total "Q" called "Qts" of the driver, and when factored with the suspension compliance Vas and free air resonance Fs, these Theile/Small Parameters can predict how the woofer or midrange driver will behave in an enclosure. _In fact, most designers work backwards and design the T/S parameters to give the desired response in a predetermined cabinet size, shape, and tuning, for the desired "target response" (how deep/powerful/tight/fast the combination of woofer and enclosure will sound).

So here's the secret of break in: when the woofer or tweeter is manufactured, the suspension is designed to be approximately 20% stiffer in compliance (Vas) than the "eventual" target, since the edge surround (and spider in a woofer/midrange driver) becomes softer and looser after being flexed for a period of time. In most dome tweeters designs, the edge surround is a "half roll" formed from the dome material itself when using fabric or soft rubber/plastic domes. In a typical metal tweeter design, a rubber half roll is attached to the dome, (although the popular Focal tweeters from France use a flat piece of foam rubber impregnated with butyl rubber "dope"). _When a typical dome tweeter is tested for suspension compliance, the measurement consists of analyzing the free air resonance frequency and how high the impedance peak (Z) will go. _After playing music or a sine wave signal for a number of hours, the tweeters Fs (free air resonance) will drop and the impedance peak (called Z) will also drop. _These mechanical changes are audible as a "softer or sweeter" sound, as the tweeter will move more freely. _After a woofer or midrange driver undergoes suspension softening, there are measurable changes in the free air resonance and impedance peaks as well, with corresponding changes in sound quality.

Many keen listeners report that brand new Von Schweikert -designed speakers sound " slightly harsh, mechanical, and bass shy". _After break in, the sound changes to "smooth, liquid, and rich."

After designing several hundred speaker systems for many clients, and having tested thousands of speaker drivers and systems over a 30 year period, I have to agree with the "Golden Ear audiophiles." __If two pairs of speakers with similar quality levels are compared, but one speaker system is "raw" (new) while the second pair is "old" and has been played for a few weeks, the "old" speaker system will outperform the new ones every time! _
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post #3 of 38 Old 05-01-2003, 06:55 PM
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Hmm... Although I have been rather skeptical about the effects of speaker break-in, I am still very much interested in the topic, and fully prepared to shift my view in response to a convincing line of scientific evidence.

With regard to the partial article above, I have several immediate questions:

(1) How much change (say % change before/after) of Vas did he actually measure? He only says "extremely wide variances" which can be interpreted any way you like.

(2) When he measured those mechanical parameters, I assume that he carefully monitored and controlled the temperature of various parts of the driver unit, especially that of the tweeter dome. But how exactly did he do it? I know that the dome of some tweeters can get seriously hot after a prolonged continuous playback with high power levels. It is also well known that a metal (especially titanium) tweeter dome serves as a heatsink by itself, and that is one of the advantages of metal domes over fabric or polymer domes. Similarly, woofer's voice coil, spider, and eventually cone can get quite warm (if not hot) after prolonged high-power playback. I am sure that the elevated temperature will have a profound (but possibly only temporary) effects on mechanical characteristics of the driver.

(3) Finally, another notion I am skeptical about in general is this assertion that these mechanical changes over time (assuming they exist) always results in an improvement of sound -- without leading to an unfortunate degradation of sound quality over time under any reasonable conditions. Doesn't it sound too good to be true (pun intended)???
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post #4 of 38 Old 05-01-2003, 07:16 PM
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I may prove myself to be a fool, but after 8 years of education in the pursuit of undergrad and graduate degrees in mechanical engineering, and a few more years of practical experience in the areas of structural design and material science, I can't recall ever noting that an elastic or elastomeric material had a pronounced drop in elastic modulus after repeated stress reversal cycling.

Any such perceived change (AFAIK) has to be a result of material yielding (or, in the case of materials in which the 'yielding' label is not entirely appropriate - matrix or other damage). IMO, relying on stress cycling to yield a joint to arrive at a more "compliant" suspension is just bad engineering. It should be entirely possible to design the proper suspension spring constant without relying on such material destruction. If it's actually matrix degradation in the whole of the foam surround or resin impregnated paper spider, well... again, bad engineering.

Of course, temperature has a profound impact on MOE, so it's possible that extended playing times could alter the sound of loudspeakers, and any measurements made after such sessions.


As I said though, I may prove myself to be a fool. If that's the case, I'd love for someone to point out some references on elastic materials changing their MOE with fatigue (not their strength, but elasticity) so that I can bring my knowledge more 'up to date.'

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post #5 of 38 Old 05-01-2003, 08:22 PM - Thread Starter
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Sushi,

Based on the article and some chats I've had with Albert, I can give you some partial responses to your questions.

Note that I am not a self-proclaimed expert on this subject, just a hobbyist who has gathered some information over the years. Some or all of it may be utter hogwash.

1) In the article itself, he states that some drivers have been designed to change by up to 20% in Vas after break-in.

2) I know he did perform some measurements on heat. However his main premise is that the compliance will change over time with use even at room temperature. That is, a "used" driver will be different after 100 hours of use, at startup at room temperature, as compared to a "new" driver at startup at room temperature.

3) He has been involved in speaker driver design and has stated that it is possible to design a driver so that it will break-in to a specific target compliance (or at least to a one within a very narrow target area). I've been told the same thing by speaker designer John Bau, and by an engineer at Dynaudio. That it is not the case that the driver continues to dramatically change over time, nor is the change random in any way. That is, they know what the compliance is going to be after 200, 500, 1000 or however many hours of use and have designed the speaker around the driver achieving that compliance figure. That the driver will then stay within the targeted area until the suspension material begins to break down (usually many years later).

Tom B.
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post #6 of 38 Old 05-01-2003, 09:29 PM
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Ok, lets give Albert the benefit of the doubt for the time being, out of respect for his experience.
What I have never been able to understand is if speaker break-in is a real phenomena, why do the speakers always sound better 100% of the time to the owners after break in? Is this by design? If so, how is it possible to design a speaker that will sound better only after it is broken in?

Russ Tarvin
If it's too loud, you're too old.
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post #7 of 38 Old 05-01-2003, 09:51 PM
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The only thing I can really think of is some matrix failure of any resin (or other) treatments to paper (or other) spider suspensions. In the deep folds, it may be that cyclic stress reversal "breaks up" (to put it crudely) some buildup of resin either on top of or embedded in the spider at those points. A possibility I guess, but I still say that's a bad engineering design. ;)

About the surround... I can't imagine why someone would purposefully design it in such a way. :confused:

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Call me weird, I actually liked the sound of my NHT 1.5's and the NHT SB1's better before the break in period (about 20 hours). This happened to me on 2 separate occasions, as I first purchased the SB1's, and then the 1.5's, so I broke them in on separate occasions.
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post #9 of 38 Old 05-01-2003, 11:29 PM - Thread Starter
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Russ,

*IF* drivers do break-in in a known way, that can be plotted and modeled, then the speaker will be designed to sound its best after break-in. Thus it is to be expected that everyone perceives them to improve, as they really would be improved.

That said, we know that there is a very definite listener break-in factor too. That when something is changed, it can take many people a little while to accommodate it and get used to the differences. So again it is very predictable that most people will perceive an improvement, even when there is no change.

So either we have: A) Speaker improves, people perceive improvement, or B) Speaker remains same, people accommodate new sound & perceive improvement.

*IF* speakers really do change, then it is quite illogical to think they would change in a random fashion wherein 50% would like the change and 50% would not. You would have to give the designers and driver manufacturers credit for knowing how their speaker/driver would change.

Thus it is no surprise that nearly everyone perceives an improvement.

Tom B.
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post #10 of 38 Old 05-01-2003, 11:46 PM
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Quote:
He has been involved in speaker driver design and has stated that it is possible to design a driver so that it will break-in to a specific target compliance (or at least to a one within a very narrow target area). I've been told the same thing by speaker designer John Bau, and by an engineer at Dynaudio. That it is not the case that the driver continues to dramatically change over time, nor is the change random in any way.
I see... If this is a well-recognized and solid know-how in the driver design community, then there should be a plenty of formal scientific publications in peer-reviewed audio engineering journals available. Is anybody aware of such papers? Too bad, I do not have resources at hand to search on scientific references in the particular field.
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post #11 of 38 Old 05-02-2003, 12:52 AM
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Sushi----JBL Pro has some break-in info in some of their spec sheets. For instance for the model 2226, a high output, high efficiency15" woofer, they state that the TS specs are stable after a 2 hour run-in and they imply it takes a far shorter time. Now JBL Pro is a no-nonsense outfit that sells drivers as tools to professional users who need to know what's actually going on, not at all like many delusional audiophiles with their wishful thinking and cockamamie theories. So I'm inclined to believe JBL Pro (with a company background and body of knowledge going back to the 1930s) over a guy like Von Runstedt who makes mere home speakers and who may be gratifying demented audiophile thinking in order to seem "with it".

Indeed some speaker designers have expressed scorn for certain audiophile thinking in private (especially bi-wiring and break-in) while acknowledgeing the need to go along with such thinking in public.

It's also instructive to do a little math, this always gets the goat of Lowther fans who think their speakers need hundreds (yes, hundreds) of hours of break-in before the highs smooth out. In 1 minute of use at 10,000 cycles the driver will cycle 600,000 times, in 1 hour that's 36 million cycles. You can see where this is going, imagine 100 hours. :-) Now we're talking about a device with suspensions made of plastic foam and linen. Imagine you had a brand new starched linen shirt. Now imagine you put it on and took it off 36 million times. Think it would still be stiff? :-)

Now my new car's engine is considered broken in after 1000 miles, it now has almost 1400 miles on it. At 70 mph if it turns 2000 rpm, in 70 miles at 70 mph it's made 120,000 turns. In 1400 miles at 70 mph that's 2,400,000 turns. This a device of steel, iron and bronze. Compare that to 36 million cycles of a device made of paper, linen and rubber. See what I mean?
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post #12 of 38 Old 05-02-2003, 06:40 AM
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Oh Well.

I am an electrical engineer. Not a mechanical engineer and I profess utter ignorance of material elasticity change with time. It seems to me that should be the case though but..... Ask anyone in the automobile world if the suspension of a new car does not require break-in. Ask any race car driver if the suspension does not require extended break-in. Note I insisted on suspension not the engine we do not have to discuss about engine break-in, it is so clear to most us as to believed to be evident..

What bugs me in this whole discussion is the fact that many people just reject what they do hear quite clearly at times. Whether they want to admit or not, they have to hear that the damn thing has changed and that its sound has gotten better. Cables, Speakers , everything in the whole audio chain. It is not an audiophile thing. it is a fact.

I hate when threads deteriorate to the point of flames and opinions. Trying to describe what one perceives is not subjectivity. Imparting emotions and opinions over the observations, is. Objectivity can come from careful human observations of phenomenon.

I am very hard pressed to accept that you do not hear the differences between a new speaker and the same speakers a few hours after. hard-pressed in all intellectual honesty

Frantz
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post #13 of 38 Old 05-02-2003, 06:44 AM
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The only downside is that a woofer could lose it's ability to handle power as it "loosens" up.
i.e. starts to flop or not keep up at high volume?
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post #14 of 38 Old 05-02-2003, 07:06 AM
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Quote:
Originally posted by FrantzM
Cables, Speakers , everything in the whole audio chain. It is not an audiophile thing. it is a fact.

I hate when threads deteriorate to the point of flames and opinions.
This thread was free of any flames, provocative statements, or opinions until you made the above statement and quite forcefully labeled your opinion as a fact. That does not sit very well with others trying to rationally discuss what could possibly be the cause for such break-in behavior.

About automotive suspensions... that break in is not due to any elastic elements (coil springs) but due to inelastic elements (shocks). There are many complex things which happen inside a typical gas or fluid filled shock absorber which cause its behavoir to change after initial cycling. I'd be grateful if you could point out the damper on a typical surround/spider loudspeaker suspension (aside from hysteresis damping, which is a material property much like MOE and does not change without permanent deformation or damage of the material in some way).

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post #15 of 38 Old 05-02-2003, 07:23 AM
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Bigus

I profess utter ignorance of mechanical engineering. I know however that material do age. their characteristics vary with usage. Now just one question. Do you or do not you hear any differences between a new speaker and one that has been ...uh aged...

A yes or no will suffice

Frantz

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post #16 of 38 Old 05-02-2003, 10:13 AM
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A few thoughts:

Speaker dealers use "it has to be broken in" to embarass customers into keeping speakers beyond the trial period, so they have to keep them.

Car springs do indeed weaken over the years, and begin to sag (flex farther with the same load), without being damaged in the process.

If you define elasticity as the ability to return to its original size, after being stretched to short of the point of damage, then steel is more elastic than rubber.

I could accept that a speaker suspension can become more supple after a lot of cycling. What I can't believe is that speaker wire has to be broken in!

Larry

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post #17 of 38 Old 05-02-2003, 10:44 AM
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Tom Brennan, I am basically in your camp, and thanks for the JBL Pro info which is, well, encouraging. ;)

Quote:
Indeed some speaker designers have expressed scorn for certain audiophile thinking in private (especially bi-wiring and break-in) while acknowledging the need to go along with such thinking in public.
Yes, and not only in private. For example, both the Axiom founder/chief engineer Ian Colquhoun, and their consultant Alan Lofft (former editor-in-chief of a Canadian audiophile magazine), have openly and flatly deny a need of lengthy speaker break-in on their forum, citing formal, blind experiments done at NRC Canada. Ian has openly said that, although they "break-in" their speakers usually for 10 hours before spec measurements, he knows it is utterly an "overkill." According to him, all measurements completely stabilizes well within the first hour of playback.

However, I personally tend to draw a line between "speaker break-in" on which I still feel there is a room for some scientific discussions, and things like "bi-wiring" and "cable/amp break-in" which I consider as utter myths.

Quote:
What bugs me in this whole discussion is the fact that many people just reject what they do hear quite clearly at times. Whether they want to admit or not, they have to hear that the damn thing has changed and that its sound has gotten better. Cables, Speakers , everything in the whole audio chain. It is not an audiophile thing. it is a fact.
Frantz, calm down please. I do not disagree with you at all that you definitely hear the differences. What I (we) are trying to discuss here is whether the perceived difference is due to a real physical change in the sound coming from the speaker, or it is due to a change in the psycho-auditory processing in your own brain, which can be evoked by your very thoughts and knowledge that you have presumably "improved" the equipment. I do not think anybody is lying, denying or rejecting anything. Just that some people here (including myself) want a more rigorous "proof" that an actual physical change, not merely a psycho-acoustic alteration, has occurred on the sound quality.
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post #18 of 38 Old 05-02-2003, 12:25 PM
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Years ago. I had a Magnepan SMG which would flap when subjected to the sound of a loud bass transient (If it is a transient then it has content in the higher frequeny but bear with me). After say 20 hours of play (a week or two). it just did not do it. anymore, never again, same amp, and everything else

From my earlier posts you can tell I am what many call a subjectivist. Scientific explanations come after the fact and, yes, people can be trained to describe very objectively what they perceive. You observe, try to assign a rational explanation to your observation and try to repeat under the same conditions. I will not dwell on the philosophical but one must first observe. The lack of rational explanation does not negate the existence of a phenomenon.

Now what I find disturbing is the length people would go to almost prove to themselves that what they hear is an illusion. They need measurements or proofs. If I can not measure it then it did not hear it. It does not exist. The Chinese have a proverb:†too far to the East lays the Westâ€. It is most fitting here
I do not think we are even close to know how to measure the multiple parameters involved in the correct reproduction of auditory phenomena. We have learned a lot but much is to be researched.

The guys from Axiom have their opinions and it should be respected but they state that they do something to their speakers for ten hours (I will not call it break-in) they believe 10 hours it is overkill ... What is the number of hours for the “kill� 2,3, 8 Hours? Now if they do not believe the additional hours or minutes make ANY difference why do they do it? It is a waste of time, when you know it will not matter? The logics of it escape me. Maybe just to be safe and have their speakers fully broken-up?

The audiophile world is really replete of BS. But they continuously push the envelope for quality in Audio reproduction. Do not dismiss ALL their observations as cockamamie without them we would have been stuck with the “Perfect Sound Forever. of the earlier CDs’ A test (blind or otherwise) that shows that most people can not reliably distinguish between amp A and amp B does not prove that there is no difference between them or that one is not superior to the other. Note the emphasis on most, this is in itself an interesting subject…
A simple yes or No would really help. Do your speakers sound the same after a few hours? I do not mind subjective impressions.



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post #19 of 38 Old 05-02-2003, 02:33 PM - Thread Starter
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Quote:
Originally posted by sushi
Tom Brennan, I am basically in your camp, and thanks for the JBL Pro info which is, well, encouraging. ;)


Yes, and not only in private. For example, both the Axiom founder/chief engineer Ian Colquhoun, and their consultant Alan Lofft (former editor-in-chief of a Canadian audiophile magazine), have openly and flatly deny a need of lengthy speaker break-in on their forum, citing formal, blind experiments done at NRC Canada. Ian has openly said that, although they "break-in" their speakers usually for 10 hours before spec measurements, he knows it is utterly an "overkill." According to him, all measurements completely stabilizes well within the first hour of playback.

This is fascinating, because I purchased a used pair of Axiom speakers, for use as rear centers in a 7.1 system. A friend heard them and purchased a new pair of the same. He brought them over to me with about 2 hours on them. With the Axioms, I noticed very little to no change at all, either through measurements (using test tones and an SPL meter) or with my ears, when comparing the new ones to my used pair.

This has been true for other speakers I've had in the past. However for three speakers, most notably the Spica TC-60 and Von Schweikert VM-2, the change was quite significant, both in measurements and observations.

But then again, last year I had all of my drivers replaced and upgraded by Von Schweikert, with the woofers being the same as in their top of the line VR-7. The break-in on these seemed very slight. However I later learned that Albert had them running for several hours before he listened to them and tweaked them a bit for me.

Personally, I believe that the majority of change in how speakers are perceived is within the listener, but there seem to be certain speakers and drivers that do physical change on break-in. And I believe that 100% of wire break-in is within the listener.

Tom B.
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post #20 of 38 Old 05-02-2003, 02:43 PM
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Now what I find disturbing is the length people would go to almost prove to themselves that what they hear is an illusion. They need measurements or proofs. If I can not measure it then it did not hear it. It does not exist.
No, you misunderstand my points...

(1) I do not claim that I would necessarily need a measurement to be convinced. A positive difference in measurements would certainly be nice and convincing, but negative data would not disprove anything.

(2) I accept totally subjective evaluations of sound quality as fully valid data, as long as the listening evaluation is properly controlled. Now, one thing you seem to underestimate is this wonderful and extremely powerful flexibility of our own brain as a sensory processor. I am not talking about an illusion. It is a real perception. However, it is well known that a true difference in sensory perception can occur without a physical difference in the sensory input, which in this case is the speaker sound. All I want to do is try to dissociate between the physical versus perceptive changes, because that would make me "subjectively" feel better! :D

(3) The only convincing way of dissociating these possibilities is to deprive the listener of his/her "knowledge" on the conditions of equipment. This is because, as long as the listener knows what he/she is listening, we cannot possibly exclude the effect of that very knowledge on his/her auditory perception. If you have a better idea on how to do this, let me know.

Quote:
Now if they do not believe the additional hours or minutes make ANY difference why do they do it? It is a waste of time, when you know it will not matter? The logics of it escape me. Maybe just to be safe and have their speakers fully broken-up?
Practically, it is very simple -- they simply leave the speaker playing overnight. No waste of time or efforts or anything, just in order to be on the safe side. I would not be surprised if they stop even doing this short "break-in," though.

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A test (blind or otherwise) that shows that most people can not reliably distinguish between amp A and amp B does not prove that there is no difference between them or that one is not superior to the other. Note the emphasis on most, this is in itself an interesting subject…
I agree. Like I said, negative data do not prove or disprove anything. My question for you is then, not talking about "most people", how about YOU? Do you hear a difference between, say, "broken-in" versus brand new cables or amps, or between $2000 versus $20 speaker cables, WITHOUT the knowledge as to which is playing? Have you done such tests yourself?

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A simple yes or No would really help. Do your speakers sound the same after a few hours? I do not mind subjective impressions.
No. I myself do not hear any subjective differences in mine. Either after several hours of playing, or after several weeks of "breaking-in." In fact, I just bought a new set of speakers a few weeks ago. They sound the same to me now, as compared with Day 1. Again, however, this is negative data, which prove or disprove nothing. That is why I would like to know more about the possible effects of speaker break-in.

Finally, your story on the Maggies is VERY convincing to me that something must have changed on the Maggies during the first 20 hours. But if they had been clearly "flapping," to me it sounds more like an overt initial defect that happened to go away spontaneously, rather than an "improvement" by a break-in. Nevertheless, something must have changed -- that much I am convinced of your story.
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post #21 of 38 Old 05-02-2003, 03:05 PM
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Various speaker components have different break-in characteristics. Some drivers don't sound any different after 1000 hours than they sound right out of the box, while others change subtley after some time. A sealed box system may require less bass break-in than a ported design because the ported driver has a stiffer spider and surround...but maybe not. All speaker systems are different, and no hard assumptions should be made.

That being said, the majority of dynamic drivers achieve 90%+ of their break-in within one hour of rigorous playback. You may be predisposed to imagining significant changes in response after 100 hours, but I respectfully suggest you are fooling yourself at this point. The temperature and humidity in the room may be a much greater factor in the sound quality.

Hook 'em up. Play 'em hard for an hour. That's pretty much what they're going to sound like. :)

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post #22 of 38 Old 05-02-2003, 04:55 PM
 
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When the NHT 2.5is came out, I had several people waiting to hear them the moment they came in. Well, the first pair came back "well, I WANTED to like them, but....." Same things with 2.9s. But, once I had them for a week or so they started selling. So, though I was skeptical about "break-in", I started paying attention to it. I had a pair of 2.9s that just came in and a guy took them home and brought them right back because they didn't sound good in his room. So, I plugged them in at the store side by side with the broken in models. It wasn't even close. I ran pink noise through them and the difference was startling. So I just ran the heck out of them for several hours and they became fairly close in sound. So he came back, picked them up and found they sounded just fine afterall. I won't doubt break-in ever again. I now warn customers that they might not sound exactly the way they did in the store, but to be patient and let them play before panicking. Several people even called weeks later and said "you know, it's a GOOD thing you warned me because I would have returned them. Now, they sound fantastic."
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post #23 of 38 Old 05-02-2003, 05:28 PM - Thread Starter
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A couple more references ...

The first from Dynaudio, one of the largest driver manufacturing companies:

"The better a driver, the longer it takes to reach its optimum
performance. Several weeks of normal usage with brand new loudspeakers,
thereafter a few minutes of warm up time is all that is required to
achieve a more optimized performance ."


Another thought on this was once expressed by John Dunlavy
in the rec.audio.high-end forum. I know John is well
respected by the audio engineers types and his thoughts on
debunking speaker cable magic have been repeated here many
times, as well as in the pages of The $ensible $ound.

"Most loudspeakers and their drivers require little or no break-in
time to achieve their level of long term performance. Indeed, 10
minutes of break-in time using music containing a wide range of
tones, especially in the low bass region of the audio spectrum
should be quite satisfactory.

However, not all woofers, mids, and tweeters are created by the
same designer using the same materials, etc. Some woofers with a
relatively stiff suspension may require more break-in time than
others. Tweeters and mids seldom (if ever) exhibit any
measurable or audible change in properties with use, despite
contrary claims by the "golden ear" set. As well, adequate
break-in usually occurs during the time required for the rigorous
testing and measurement procedures given loudspeakers by
manufacturers concerned with insuring the accuracy and
consistency of their products.

Best of listening!

John Dunlavy
Dunlavy Audio Labs"

John's statements may explain why some people, and even some manufacturers, will claim that break-in, if it exists at all, should be accomplished within the first hour. Yet others, of equal reputation, claim that long break-in periods are needed to achieve optimal results.

Tom B.
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post #24 of 38 Old 05-02-2003, 08:10 PM
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Great discussion.

My story: I purchased the new ACI Sapphire. I listened to them for an hour, then put them in my basement and ran them for approximately 100 hours. I then listened to them again and noticed improvements - but realized the 'improvements' could all be in my head because I want to hear them.

Fastfoward one month and I was able to A/B a new Sapphire vs my 'broken-in' Sapphire in my own setup. I unplugged an RCA cable from my amp, not knowing the amp was on. I though the line conditioner had switched off when it hadn't yet shut down the switched outlets. Poof went one of the woofers (it was extended about 1/2").

After I installed the replacement woofer I listened to my system, one speaker with 150 hours, one with 0 hours. There was quite a difference in the midrange between the two. The 'old' speaker sound much better.

I put the 'new' speaker in my basement and ran it for 50 hours. I did the comparison again and I could not tell the difference between the two.

For that particular Vifa driver, my initial break-in of 100 hours now seems like it was overkill, as there was no difference between 50 hours and 150 hours.

I realize it isn't a controlled scientific experiment, but I still found it interesting.

Kevin
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post #25 of 38 Old 05-02-2003, 08:29 PM
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The manual for my PMC's say that they need 8 hrs of break in. The dealer I bought them from recommends 200+ hrs at a relatively high volume to break them in. I probably have 15 hrs of a relatively high volume use on these speakers. They sound pretty much the same to me during this time. To this point it, the break in has not been a dramatic life altering experience that some trade rags would lead you to believe. Of the past speakers I owned that were bought new, I don't recall huge sonic improvements over time - minor ones at best.

Eric Chong

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post #26 of 38 Old 05-02-2003, 11:21 PM
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What's telling to me fellas is that the old-time hi-fi guys didn't go on about speaker break-in, nor about the sound of different wires and other things modern audiophiles worry about. Now these guys had gear that was every bit as good as that today (some say better) but they didn't hear all this stuff. Now these were hard-nosed guys who'd been through the Great Depression and had fought the Germans and Japanese to boot. They were also far more more technically astute than the average modern audiophile. In other words they were tough, savvy, hard to con and didn't have any time for or patience with a bunch of BS.

It isn't until the Baby Boomers come into dough in the 70s that we start hearing about this stuff, about the same time that the term "hi-fi" wasn't good enough for some people any more and the term "high-end" came into play. Now the Baby Boomers are the most spoiled, self-centered, self-congratulatory, drug-addled and delusional generation in American history; it's no surprise to me that the demented aspects of this hobby took off big time when the Boomers became involved.
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post #27 of 38 Old 05-02-2003, 11:36 PM
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Quote:
Originally posted by Larry Fine
Car springs do indeed weaken over the years, and begin to sag (flex farther with the same load), without being damaged in the process.
Car springs are typically made from steel. Any "sag" in the actual springs over the years is due to either permanent set (yielding, i.e. damage) of the material, or shifting of bolted connections, or some miracle that annealed the spring and relieved stresses when compressed. Or, most likely, it is due to the shocks... most use compressed gas chages which have a spring constant of their own, and certainly change over time. People replace "shocks" on their cars fairly often. How often do people replace coil springs?

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If you define elasticity as the ability to return to its original size, after being stretched to short of the point of damage, then steel is more elastic than rubber.
I'll admit, I plan on doing more research on visco-elsatic and elastomeric materials to get a better understanding of how material properties might change with repeated stress reversals. AFAIK, there aren't material properties of polymers or natural rubbers that describe such behavior. It is possible though that the properties can change as a matter of aging (not stressing), whereby certain chemical processes alter the material structure, and hence the properties. If I find anything interesting, I'll let you guys know.

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post #28 of 38 Old 05-02-2003, 11:51 PM
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FrantzM,

I've purchased a pair of MMG's and a MGCC new, and experienced no change in sound. All the other speakers I've owned however I purchased used, so I don't have a very wide sampling upon which to base a response to your question.

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post #29 of 38 Old 05-03-2003, 02:17 PM
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Just to experience the immense power of perceptive information processing of our own brain (and how it can be dramatically influenced and adapted), see this picture:

http://members.lycos.nl/amazingart/i...ckershadow.jpg

Now, which is darker -- the square "A" or "B"?
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post #30 of 38 Old 05-03-2003, 04:24 PM
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They are identical. Next?

Larry

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