Why the Harman mono speaker test was wrong for dipole planers

[DaveC]

Again, why are the subjective effects of burn-in always reported as being positive?

I'd guess it's because during the burn-in process the component moves closer in performance to it's intended design.

 

[microstrip]

Again, why are the subjective effects of burn-in always reported as being positive?

Not always. Many people, me included, have reported that with some equipment performance degrades significantly during a few hundred hours and only then the derive starts to become positive.

We expect that manufacturers selected their components to reach a final equilibrium state that we consider better. It is not always the case - a good friend of mine claimed that after burn-in his system become different (too soft) and felt disappointed. Who knows? I am sure your psychology book can explain all the hypothesis!

BTW, tube equipment has easily measurable differences during burn-in of tubes. But we are diverging.

 

[Robh3606]

I'd expect drivers to all be different depending on the design, materials and how much the drivers were tested at the factory, if at all.

Hello Dave

I have a pair of JBL 2216 15 woofers used in the M2 monitor that were power tested for 100hrs at 38 volts from 40hz-400 hz which is a brutal test. Even after this measuring them on a Woofer Tester 2 they still meet the T/S parameters within the tolerances on the spec sheet. So I think it's like you said careful choice of materials and really well controlled manufacturing processes. Considering the application you don't want the performance to change with time especially the way the DSP is set-up.

Rob

 

[Gregadd]

While we are at it let's not forget warmup.

 

[amirm]

While we are at it let's not forget warmup.

And stretching...

 

[Blizzard]

Ok but what hasn't been invented yet?? That is what I was wondering. Especially with respect to the effects of changes due to aging/burn in with passive components. Any decent simulator like LEAP will show you the effects due to any value changes.

Rob

We could fly before airplanes were invented too. We just didn't know how to yet.

 

[microstrip]

While we are at it let's not forget warmup.

Fortunately warm-up is legalized by Stereophile practice of running amplifiers at one third full power before taking measurements ...

 

[es347]

I've owned three prs of ML speakers over the years and every single one sounded like crap out of the box and that was not my imagination. It was common knowledge that MLs could not be judged until somewhat broken in. One can argue regarding the merits of burn in when it comes to cables or perhaps amplifiers but when it comes electrostatics, at least MLs break in is a fact of life...IMHO...

 

[microstrip]

Ok but what hasn't been invented yet?? That is what I was wondering. Especially with respect to the effects of changes due to aging/burn in with passive components. Any decent simulator like LEAP will show you the effects due to any value changes.

Rob

If people invest time and money they can study them. However no one is really interested in spending a fortune to know why audiophiles prefer brand X of capacitors to brand Y.

Interesting you refer to simulators. I was told at a seminar about simulation tools for analog electronics that modern simulators are very powerful and can simulate small effects that can not be easily measured, particularly due to temperature transients. The spokesman was very clear - the old way was designing, simulating, assembling, measuring and making changes. Now-a-days things have changed a lot. The designer designs and simulates in his workstation, and checking is performed mostly by a colleague in the same simulator ! For many applications the breadboard and the oscilloscope are gone away. Surely this does not exclude listening to validate design concepts and the evolution of the design.

 

[Robh3606]

Fortunately warm-up is legalized by Stereophile practice of running amplifiers at one third full power before taking measurements ...

That is preconditioning and has nothing to do with Stereophile. You can't advertise you are x watts without passing the 1/3 power 1 hour test. That goes back to when cheap electronics were rated at 400 watts per xyz and there were no standard methods.

Rob

 

[microstrip]

I've owned three prs of ML speakers over the years and every single one sounded like crap out of the box and that was not my imagination. It was common knowledge that MLs could not be judged until somewhat broken in. One can argue regarding the merits of burn in when it comes to cables or perhaps amplifiers but when it comes electrostatics, at least MLs break in is a fact of life...IMHO...

Electrostatics are a different fish - I think no one will deny they need burn-in. I could compare a well burn-in and a new pair of equal SoundLab PX panels side by side in my system. One pair was in current use, the other one was the spare, kept in storage about four years. I will not refer to difference between them for fear of the hyperbole brigade! It took a few weeks of intensive play in another room until the "fresh" panels could sound "full" and "being there" as the older ones.

A good friend come to my listening room while the new panels were recently connected - his immediate reaction was " What is broken?" His second comment listening to a CD he brought: "My system sounds much better than yours!" And I could not say anything. Considering his system is in great part my previous system it was a supreme humiliation ...

 

[Rodney Gold]

Again, why are the subjective effects of burn-in always reported as being positive?

Called acclimatisation...and some cognitive dissonance thrown in for good measure

 

[Gregadd]

I've owned three prs of ML speakers over the years and every single one sounded like crap out of the box and that was not my imagination. It was common knowledge that MLs could not be judged until somewhat broken in. One can argue regarding the merits of burn in when it comes to cables or perhaps amplifiers but when it comes electrostatics, at least MLs break in is a fact of life...IMHO...

That wpuld also be true of the replacement panels I purchased. I had not made the point because I've done it before. I can't imagine rapaid switching of ML to short clips of music would alow them to "shine.'" Warm up is eqully critical.

 

[Kal Rubinson]

Not always. Many people, me included, have reported that with some equipment performance degrades significantly during a few hundred hours and only then the derive starts to become positive.

We expect that manufacturers selected their components to reach a final equilibrium state that we consider better. It is not always the case - a good friend of mine claimed that after burn-in his system become different (too soft) and felt disappointed. Who knows? I am sure your psychology book can explain all the hypothesis!

I have to say that your post is the very first I have ever read to report a performance degradation over time. However, I am skeptical about the prescience of manufacturers although I think most do intend for their products to maintain intended performance. As for psychology, one can conjure principles to explain all but that is not proof, either.

 

[Kal Rubinson]

Fortunately warm-up is legalized by Stereophile practice of running amplifiers at one third full power before taking measurements ...

For measurements, yes, but not for listening.

 

[FrantzM]

Hi
For the record I am not a burn-in believer ...

This said back in the day (warning, repeating an anecdote! ) Almost 20 years ago.. I had a MG 3.x (can't remember which one) which would flap on loud bass transient ( an oxymoron?!) .. After a few days on same amp in same system, same everything, the the "flap" sound disappeared to never return.. I did not measure the SPL at which it occurred: I just put the volume control at the same settings...

 

[microstrip]

For measurements, yes, but not for listening.

Curiously some of their reviews refer clearly to burn-in and warm-up. And the Stereophile CD3 includes a track for burn-in [20] "Caca-cophony": Stereophile's Special Burn-In Noise (DDD) 2:15 Read more at http://www.stereophile.com/content/istereophilei-test-cd-3-signals-testing-loudspeakers-rooms#R0ptLyZYT4XGMDkb.99. It was specially chosen and recorded with great care by John Atkinson. I noticed you were not on the players list. Did you object to it?

 

[Kal Rubinson]

Curiously some of their reviews refer clearly to burn-in and warm-up.

This is ad hoc and I doubt if anyone wants to tolerate the 1/3-power treatment.

And the Stereophile CD3 includes a track for burn-in [20] "Caca-cophony": Stereophile's Special Burn-In Noise (DDD) 2:15 Read more at http://www.stereophile.com/content/istereophilei-test-cd-3-signals-testing-loudspeakers-rooms#R0ptLyZYT4XGMDkb.99. It was specially chosen and recorded with great care by John Atkinson.

I have that and others. I do not usually bother with them unless the speaker manufacturer insists on using one of them. For example, when I got the new B&W 802D3s two weeks ago, it was requested that I run the XLO burn in tracks, so I did. I see no harm in it and it means that they cannot complain that I didn't employ their recommended procedures.

I noticed you were not on the players list. Did you object to it?

No. The disc was produced in 1990 and I joined the magazine in 1996. OTOH, I would have been happy to participate but would not commit to using the disc. FWIW, I get the discs for their music tracks or sound effects. I still scare people with the "Garage Door."

 

[dallasjustice]

Why does burn-in suddenly stop? When does it stop?

Or. . . Maybe it just keeps going until the system sounds terrible from overuse??

 

[microstrip]

(...) I have that and others. I do not usually bother with them unless the speaker manufacturer insists on using one of them. For example, when I got the new B&W 802D3s two weeks ago, it was requested that I run the XLO burn in tracks, so I did. I see no harm in it and it means that they cannot complain that I didn't employ their recommended procedures.

Interesting. The B&W 802 diamond used Munforf exotic film capacitors, known for needing some burn-in. Perhaps it is why they are requiring the burn-in.

No. The disc was produced in 1990 and I joined the magazine in 1996. OTOH, I would have been happy to participate but would not commit to using the disc. FWIW, I get the discs for their music tracks or sound effects. I still scare people with the "Garage Door."

Curiously, sometimes I get scared my self inadvertently by the banging on the garage door of the HifiNews test CD!