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The Harbeth User Group is the primary channel for public communication with Harbeth's HQ. If you have a 'scientific mind' and are curious about how the ear works, how it can lead us to make the right - and wrong - audio equipment decisions, and about the technical ins and outs of audio equipment, how it's designed and what choices the designer makes, then the factual Science of Audio sub-forum area of HUG is your place. The objective methods of comparing audio equipment under controlled conditions has been thoroughly examined here on HUG and elsewhere and should be accessible to non-experts and able to be tried-out at home without deep technical knowledge. From a design perspective, today's award winning Harbeths could not have been designed any other way.

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The Myth of "Break-in"

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  • The Myth of "Break-in"

    I thought the subject (myth) of 'break-in' was apt for an Audio Evaluation section.

    I'm currently engaged elsewhere in a debate over the concept of audio equipment 'breaking in,' and wanted to point some of those people to some really interesting posts I've read over here, but I'm having trouble finding them.

    I know for a fact I have read a post from Alan, saying essentially that if a speaker were to physically change during its initial hours of use, it would be considered defective (I'm paraphrasing, of course - I hope I'm not misrepresenting the spirit of what he said). Could anyone point me to this post?

    I'm also an adherent to the psychological theory of so-called break-in; it's simply one's brain adjusting to a new piece of audio equipment. I also like to compare it to the ancient therapy of acupuncture; break-in apparently works with practically everything: speakers, headphones, DAC's, cables, etc. Acupuncture is apparently the miracle cure for everything from depression to skin rashes. The evidence for both seems to be unscientific and circumstantial.

    If anyone could post some scientific studies on break-in - either from within the HUG or externally - it would be most appreciated.

  • #2
    Possible suspension exercising

    I don't think I have any scientific studies to refer to, but as far as I know break in of electronic components and perhaps even more so of cables is utter nonsense. Break in of electromechanical devices like speakers may be real. The cone material and particularly the surrround may have some initial stiffness that they need to loose. Physically this is conceivable, but not necessarily of great importance.

    I have never heard major differences, and I would not expect this break in to need more than a short period of at most a few hours. I have never seen test results.

    Comment


    • #3
      Yet more bulshittery

      Originally posted by Pablo View Post
      I thought the subject (myth) of 'break-in' was apt for an Audio Evaluation section.

      I'm currently engaged elsewhere in a debate over the concept of audio equipment 'breaking in,' and wanted to point some of those people to some really interesting posts I've read over here, but I'm having trouble finding them.

      I know for a fact I have read a post from Alan, saying essentially that if a speaker were to physically change during its initial hours of use, it would be considered defective (I'm paraphrasing, of course - I hope I'm not misrepresenting the spirit of what he said). Could anyone point me to this post?

      I'm also an adherent to the psychological theory of so-called break-in; it's simply one's brain adjusting to a new piece of audio equipment. I also like to compare it to the ancient therapy of acupuncture; break-in apparently works with practically everything: speakers, headphones, DAC's, cables, etc. Acupuncture is apparently the miracle cure for everything from depression to skin rashes. The evidence for both seems to be unscientific and circumstantial.

      If anyone could post some scientific studies on break-in - either from within the HUG or externally - it would be most appreciated.
      Speaker break in might be a real factored in detail by design?? but for the main I absolutely ignore any talk of break in, you can even buy 'cable cookers', things that seemingly run a current? through a speaker cable to break it in fast, I will put my neck out now and say without any hesitation that is pure distilled audio bullshittery and I defy any clown who suggests a cable needs to be broken in.

      Edit: I recall owners/reviewers leaving on equipment for weeks before they listen 'critically' and only then proclaim the subjective qualities of sound. Would it be possible to play a trick on such a person and turn the equipment on/off a few minutes before they do this??
      Getting to know my C7ES3

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      • #4
        Once more about pseudo-knowledge - burn-in is another non-issue

        Text repeated from a thread about small Harbeth monitors:

        As we deal with real materials in real life, we must understand that neither impregnated cloth inner suspension (spider) nor the most modern elastomer outer one (surround) of speaker’s cone are of ideal “springiness” also that they are compound products / materials that will change (a very bit) their mechanical properties under usually subtle but dynamic load they are influenced.

        Beneath the data of common modern transducer (midwoofer) with electro-mechanical properties as freshly manufactured and “burned in”. As we can see the suspension compliance increases a bit (it gets a very little “softer”), but believe me from final user’s point of view (and his ears) it is really insignificant.

        http://www.wavecor.com/WF182BD09_10_...ifications.pdf

        Explanation of all those “mystic” qualitative values - http://en.wikipedia.org/wiki/Thiele/Small

        Normally driver goes to its long term characteristics after … two to ten records audited (although sometimes it can last a bit longer in case of older technologies applied – very rare transducers in today market). Let’s calculate midwoofer suspension’s average “dynamic work” after one CD - 1kHz x 60sec x 60min = 3.600.000 cycles! Usually it is said that high quality constructional steel gets its long-life properties under dynamic load after few millions of cycles (Wohler's curve). Pretty much, isn’t it?

        Topic itself is very interesting maybe from educational side, but please forget about this audiophoolic fetish - “burning in” professionally manufactured loudspeakers – music matters!

        The best seasonal greetings.

        Comment


        • #5
          "Break-in"

          My understanding was that any break-in with speakers happened in the first 10 or so seconds, but I will check out your links with interest.

          And sure, there will be physiological changes after that over time, but this isn't "break-in" as audiophools (I like that word!) understand it; in other words the speaker isn't changing for the better, necessarily. If anything, it's degrading, albeit very slowly.

          Comment


          • #6
            Simpler than you could imagine

            Originally posted by Pablo View Post
            My understanding was that any break-in with speakers happened in the first 10 or so seconds, but I will check out your links with interest.

            And sure, there will be physiological changes after that over time, but this isn't "break-in" as audiophools (I like that word!) understand it; in other words the speaker isn't changing for the better, necessarily. If anything, it's degrading, albeit very slowly.
            Actually, the real situation is pretty basic stuff. The (usually) yellow suspension ring hidden under the cone, called in the trade the spider, is nothing more or less than resin impregnated woven fabric.

            When flexed a few times, the sheet of resin presumably takes on micro fissures, and once that process has occurred - over perhaps the first few hours or so under normal home use, accelerated in the test lab by playing very loud - the fundamental resonance frequency of the woofer drops by a few percent (utterly inaudible, difficult to even measure) and that's it, forever. Any perception that the sound has subjectively improved after hiours, days or weeks is entirely and totally in the listener's imagination. They may well truly believe that, buit it is nothing more than familiarisation, a very common human experience. When I changed car recently I was amazed at the ride, the power and the handling. Two weeks later, it all seemed perfectly unremarkable to me.

            When designing a new model and preparing 'golden reference' drive units, just to be sure I exercise them (a much more meaningful world than burn-in) in the lab at a high sound pressure but at subsonic frequencies where for/aft motion is high for an hour, then carefully measure their ultimate, settled, final characteristics.
            Alan A. Shaw
            Designer, owner
            Harbeth Audio UK

            Comment


            • #7
              Long service assurance

              Originally posted by Pablo View Post
              My understanding was that any break-in with speakers happened in the first 10 or so seconds, but I will check out your links with interest.

              And sure, there will be physiological changes after that over time, but this isn't "break-in" as audiophools (I like that word!) understand it; in other words the speaker isn't changing for the better, necessarily. If anything, it's degrading, albeit very slowly.
              In the past we had some problems with foamy surrounds, today modern elastomers give guarantee of stable driver's work for couple of decades, no issue at all. Take care of your loudspeakers as described in manual and they will serve you for long.

              Comment


              • #8
                Subsonic vinyl replay

                Originally posted by A.S. View Post
                Actually, the real situation is pretty basic stuff. The (usually) yellow suspension ring hidden under the cone, called in the trade the spider, is nothing more or less than resin impregnated woven fabric.

                When flexed a few times, the sheet of resin presumably takes on micro fissures, and once that process has occurred - over perhaps the first few hours or so under normal home use, accelerated in the test lab by playing very loud - the fundamental resonance frequency of the woofer drops by a few percent (utterly inaudible, difficult to even measure) and that's it, forever. Any perception that the sound has subjectively improved after hiours, days or weeks is entirely and totally in the listener's imagination. They may well truly believe that, buit it is nothing more than familiarisation, a very common human experience. When I changed car recently I was amazed at the ride, the power and the handling. Two weeks later, it all seemed perfectly unremarkable to me.

                When designing a new model and preparing 'golden reference' drive units, just to be sure I exercise them (a much more meaningful world than burn-in) in the lab at a high sound pressure but at subsonic frequencies where for/aft motion is high for an hour, then carefully measure their ultimate, settled, final characteristics.
                Interesting. Loud subsonic signals are probably common for the vinyl user (without any filtering) their bass cones will probably be flexed much further than people playing music from a CD source for eg. especially as by the time vinyl replay is as loud as CD the bass cones can be flapping considerably.
                Getting to know my C7ES3

                Comment


                • #9
                  Changes in Thiele-Small parameters due to burn-in are "self-levelling"

                  Originally posted by pkwba View Post
                  Beneath the data of common modern transducer (midwoofer) with electro-mechanical properties as freshly manufactured and “burned in”. As we can see the suspension compliance increases a bit (it gets a very little “softer”), but believe me from final user’s point of view (and his ears) it is really insignificant.

                  http://www.wavecor.com/WF182BD09_10_...ifications.pdf
                  The specifications do indicate that there is a significant change in Thiele-Small parameters for this driver after burn-in. However, what normally seems to happen is that the box tuning isn't as sensitive to that change as what might initially be expected. An increase in Vas is offset by the decrease in Fs and the corresponding decrease in Qts. The low-frequency response isn't greatly affected by these changes.

                  The driver is quite an interesting one from another perspective. It has some very high-Q breakup resonances at the upper end of its frequency bandwidth. Those will no doubt give this transducer a significant sonic character, as it's not really possible to tame them precisely.

                  Comment


                  • #10
                    Speaker suspension softening

                    Originally posted by witwald View Post
                    1. The specifications do indicate that there is a significant change in Thiele-Small parameters for this driver after burn-in. However, what normally seems to happen is that the box tuning isn't as sensitive to that change as what might initially be expected. An increase in Vas is offset by the decrease in Fs and the corresponding decrease in Qts. The low-frequency response isn't greatly affected by these changes.

                    2. The driver is quite an interesting one from another perspective. It has some very high-Q breakup resonances at the upper end of its frequency bandwidth. Those will no doubt give this transducer a significant sonic character, as it's not really possible to tame them precisely.
                    ad.1 Exactly, the "softening" cone's suspension has nothing to do with "sonic" perception of the driver, another myth popularized by mystic votaries of voodoo electro-acoustics.

                    ad.2 It is a compromise between wish to achieve "low" frequencies from relatively small cabinet and driver (low total Q and necessary stiffness of a piston), wish to reach rather high midrange and mass production of membrane. High order crossover or additional circuitry essential. Demands of the trendy marketing.

                    In my opinion very well made product but some compromise anyhow. But it is small digression only .
                    After long journey around modern techniques I personally prefer the idea of monitor loudspeaker worked out by professional companies and institutions in late 60s and seventies. Or rather its gradual evolution and improving. The progress of materials science and production technology give us today much better, more stable and predictable drivers for designer's use. I wonder how happy fathers inventors of modern loudspeakers' production would be if they had today possibilities at hand.

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