Do Audio Speakers Break-in?

[Bach]

My postulation is:

B = P / 100.
Where B is the break-in time in hours and P is the price per pair in €.

 

[Head_Unit]

Why would an engineer design a driver to certain specifications if its characteristics were to change over time?

I'm not sure exactly how you mean that, but changes over time have to be taken into account in myriad engineering disciplines, from bridges to tires to batteries. For speakers a not-on-point example is that back in the day you could calculate "ideal" enclosure sizes for JBL pro woofers, and find the ideal enclosure would be placing the driver face down on the floor, because the Qs were so low. Now in an enclosure at a concert with the coil heated up to the temperature of Venus, the parameters became something else. More specific to the suspensions, I certainly don't know every loudspeaker designer on Earth but none of my coworkers or friends at other companies ever worried much at all about this issue. Even big customers like Ford or Mazda didn't worry about it directly-we had to do long-term durability testing with some tolerance as to frequency response (which encompasses any break-in issues...there was indeed break in but not much and with very little effect on the frequency response).

 

[cavedriver]

I had a pair of Infinity Kappa car audio speakers that sat on the shelf for years before I installed them. When I did install just one of them I noticed a "thunk" from the woofer during music playback. After a while the sound went away. I have not re-opened the car door to inspect the woofer to see if any insulation or other car parts are touching the woofer. Since I have not installed the other woofer I may bench test it before I install it. I suspect with the years it sat on the shelf it had a good chance to become quite stiff. To be clear, this is an extreme example that could create a measurable (even audible) difference in performance, and not the normal experience for "new" drivers.

 

[Spocko]

As humans we crave the mysticism of rituals like "break in" and similar processes that elevate the equipment to more than just a fungible commodity. This is no different than sprinkling holy water or knocking on wood.

 

[Sal1950]

sorry that's nonsense, and the comparison is totally spurious.
I have made race engines for years.

If you have built race engines you know they are built to slightly different spec than a street motor.
I would allow may an extra .001 piston to wall clearance and .0005 for rod ends and crank journals.
Heat built up during initial break-in of new parts from increased friction can be extreme and race engines
get no chance break-in.

 

[Deleted member 48726]

sorry that's nonsense, and the comparison is totally spurious.
I have made race engines for years.
If you have to break anything in on such an engine you have built it wrong, no matter if it's a mid 60s Aston Martin engine or a mid 90s supercharged or V12 unit.

I can understand some of those low tech 1950s Yankee V8s might need TLC, but NAH, I believe break in on a properly made race engine about as much as break-in on properly engineered speakers.

All entirely imaginary.

Very bombastic of you. It looks silly when you are completely wrong at the same time.

I have a somewhat multidisciplinary skillset. I was once involved in overhauling numerous medium gensets. I can assure you that there is procedure IR to run-in. I also have experience with car engines like you seem to have. Once overhauled or replacing with a crate engine, the manufacturer had a special run-in oil which had lower viscosity than ordinary.

In either case, being an 800 kWel. genset engine or the 80 kWmech crate engine, there was run-in. As witnessed by looking at the oil when changing it; it glistened and contained various metals from the break-in period.

And a dedicated race engine CAN NOT be compared to industrial and residential units.

 

[Deleted member 48726]

As humans we crave the mysticism of rituals like "break in" and similar processes that elevate the equipment to more than just a fungible commodity. This is no different than sprinkling holy water or knocking on wood.

As humans we crave to simplify and make things we don't quite comprehend into a black and white turf war. This is no different than blind faith.

 

[Deleted member 48726]

Why does Chevy recommend limiting RPM's for a certain # of miles on the new Corvette?

When a new owner takes delivery of the Corvette Z06, the tachometer will have a redline of 6600 RPM for the first 500 miles and then will reset to its 8600 RPM redline afterward.Feb 22, 2022

BMW does that with some of their high performing motor cycles as well.

 

[Deleted member 48726]

If you and he are talking about the Hexibase video on youtube, AFAICT it fails in two stunning respects:

1) no measure of unit to unit variation when new --- i..e the true baseline
2) no measure of unit change at timepoints between 'new' and '3 years of use'

Oh, really? -Then none of the measurements here on ASR are valid because there is no "true baseline" due to lack of test specimens.
Come to think of it, this discards 99.82 % of all audio equipment measurements, tests and reviews.

How many units will you consider enough to establish the "true baseline" ? 2, 4, 6? -Or should it be in percentage of produced units?

 

[Deleted member 48726]

Manufacturing tolerances, perhaps. Mass produced engines are not the same as carefully manufactured racing engines. In F1 cars, the tolerances are so tight that the engines seize when they are cold. Only when the engine is heated do the cylinders expand, and the pistons are able to move freely. Before F1 cars are started, they have to circulate hot oil through the engine.

Since we are talking about cars, I was told that tyres also have "burn in". Every time I get new tyres fitted, I am told to be careful for a few hundred km because new tyres do not grip as well. I assumed it was to do with compounds in the rubber that need to be worn off by the road. I don't know if this is true.

All true.

IR to tyres there is a smooth layer on top of the rubber due to the manufacturing process. This needs to wear off before the tyre properties are met.

 

[valve_integrator]

Very bombastic of you. It looks silly when you are completely wrong at the same time.

I have a somewhat multidisciplinary skillset. I was once involved in overhauling numerous medium gensets. I can assure you that there is procedure IR to run-in. I also have experience with car engines like you seem to have. Once overhauled or replacing with a crate engine, the manufacturer had a special run-in oil which had lower viscosity than ordinary.

In either case, being an 800 kWel. genset engine or the 80 kWmech crate engine, there was run-in. As witnessed by looking at the oil when changing it; it glistened and contained various metals from the break-in period.

And a dedicated race engine CAN NOT be compared to industrial and residential units.

It's truly incredible the amount of BS spouted here and above.
It's almost as bad as the forums and audiophile reviews.

If I even refer to a F1 engine, no unit is EVER run for motor racing at high level without it having first been run and set up on an engine dyno and run up to full power. That says it all.

I did refer to Aston stuff which was about as close as you would get to a competition engine 50-60yrs ago.
They were always run first on a dyno, as they were at Jaguar.
It might not occur to anyone here, but Jaguar were the biggest customer for Heenan-Froude, because almost no other major manufacturer at the time did this.
How anyone can compare a generating set which runs probably in the 600-900rpm range and has to run for up to a decade to a to a well built comp engine running to 5000-7000rpm beats me.

In this respect it's the comparison between some sort of PA speaker system for rock concerts in open air, which have listening distances up to 300m, compared with a fine home stereo/surround system with transducer - ear distances not exceeding 5m inside a walled building.
TBQH, I would be quite suprised if in the quality control division of some of the scandinavian speaker driver firms if they didn't do pretty severe QC at the production end.
They, like major car engine makers have a reputation to guard.

GM (corvette) like any other manufacturer probably does the REV safeguard for the first 500kms in order to protect their stuff from stupid customers.
(There is nothing more stupid than a customer!), who would insist on trying a cocaine fuelled show off and blow one up with a well internet published warranty claim...

As for the speaker break in crap, it's like the fancy cable, skin effects, et al.
If the driver manufacturer is unable to guarantee his specs, then his quality control is bs, and shouldn't be in the high end at all.
I'm with Amir on this, - All break -in entirely imaginary.

 

[Keith_W]

I'm with Amir on this, - All break -in entirely imaginary.

I think most of us agree with you that audio break-in is imaginary. However - the statement you made was that ALL engine break-in is "nonsense". The arguments against you posted above, are not arguing that audio break-in is real. Only that break-in occurs in other mechanical devices including car engines. I could give you a few more examples of non-audio "break-in", like cast iron pans acquiring a non-stick coating with several uses, leather shoes getting more comfortable after a few wears, toothbrushes are less harsh on your gums after you use it for a few days, CT and MRI scanners losing calibration (our radiol department calibrates new scanners upon delivery and again a week later).

 

[Deleted member 48726]

1) It's truly incredible the amount of BS spouted here and above.
It's almost as bad as the forums and audiophile reviews.

2) If I even refer to a F1 engine, no unit is EVER run for motor racing at high level without it having first been run and set up on an engine dyno and run up to full power. That says it all.

I did refer to Aston stuff which was about as close as you would get to a competition engine 50-60yrs ago.
They were always run first on a dyno, as they were at Jaguar.
It might not occur to anyone here, but Jaguar were the biggest customer for Heenan-Froude, because almost no other major manufacturer at the time did this.
How anyone can compare a generating set which runs probably in the 600-900rpm range and has to run for up to a decade to a to a well built comp engine running to 5000-7000rpm beats me.

3) In this respect it's the comparison between some sort of PA speaker system for rock concerts in open air, which have listening distances up to 300m, compared with a fine home stereo/surround system with transducer - ear distances not exceeding 5m inside a walled building.
TBQH, I would be quite suprised if in the quality control division of some of the scandinavian speaker driver firms if they didn't do pretty severe QC at the production end.
They, like major car engine makers have a reputation to guard.

4) GM (corvette) like any other manufacturer probably does the REV safeguard for the first 500kms in order to protect their stuff from stupid customers.
(There is nothing more stupid than a customer!), who would insist on trying a cocaine fuelled show off and blow one up with a well internet published warranty claim...

5) As for the speaker break in crap, it's like the fancy cable, skin effects, et al.
If the driver manufacturer is unable to guarantee his specs, then his quality control is bs, and shouldn't be in the high end at all.
I'm with Amir on this, - All break -in entirely imaginary.

1) No, what I wrote is entirely true.

2) I did write that they CAN NOT be compared.

3) A driver is a driver. And they are built differently, so they have break in in various degrees whether a PA or a residential one. Who even brought PA into the discussion?

4) I don't think it's the reason. I think break in is the reason. Isn't the service interval also lower on the first check? -I bet it is. I know they where 25 % or so in mileage on the first check on cars in general.

5) I don't agree. And I have provided examples e.g. video with old vs. new identical driver and link to a manufacturers procedure before T&S measurements that says to pre-condition the driver before carrying on. So in conclusion; it IS NOT imaginary and it isn't gonna be upon repeating the phrase.

 

[valve_integrator]

1) No, what I wrote is entirely true.

4) I don't think it's the reason. I think break in is the reason. Isn't the service interval also lower on the first check? -I bet it is. I know they where 25 % or so in mileage on the first check on cars in general.

1/ repeating oxymorons doesn't make them any more valid.

2/ You clearly know very little about the subject.
Honing is a science.
Piston ring material and shape is a science, which I happen to know quite a bit about.
I have worked a lot with Cosworth material, and SIM (swiss), Goetze (D) and NPR.
Best thing is not to come out with your "opinions" when it's not based on anything other than blabla.
The reason for an oil change after 20 mins of running on a thin low grade oil, is quite simply bedding and loss of metal.

It has sweet F-A to do with speakers which by nature don't have metal to metal contact or deliberate wear-in on mating cross hatched surfaces.

As for PA systems, it's also clear there is zilch difference between a bright new system and a well aged one.
The main problem is, they are not hifi, they are designed to resist being run flat out for ours and dissipate any Kw of heat....all horses for courses eh?

Some of this stuff of course I can't believe I am reading.
Someone is gonna tell me next electrostatics also need "burn in". hahaha!
What more crap is gonna appear here?
shoes? toothbrushes? WTF?!

 

[Keith_W]

The old adage applies here. Be careful about making blanket statements. You said "all break-in is entirely imaginary". That's a blanket statement, and it's not true. With audio only, probably true.

 

[Deleted member 48726]

1/ repeating oxymorons doesn't make them any more valid.

2/ You clearly know very little about the subject.
Honing is a science.
Piston ring material and shape is a science, which I happen to know quite a bit about.
I have worked a lot with Cosworth material, and SIM (swiss), Goetze (D) and NPR.
Best thing is not to come out with your "opinions" when it's not based on anything other than blabla.
The reason for an oil change after 20 mins of running on a thin low grade oil, is quite simply bedding and loss of metal.

It has sweet F-A to do with speakers which by nature don't have metal to metal contact or deliberate wear-in on mating cross hatched surfaces.

As for PA systems, it's also clear there is zilch difference between a bright new system and a well aged one.
The main problem is, they are not hifi, they are designed to resist being run flat out for ours and dissipate any Kw of heat....all horses for courses eh?

Some of this stuff of course I can't believe I am reading.
Someone is gonna tell me next electrostatics also need "burn in". hahaha!
What more crap is gonna appear here?
shoes? toothbrushes? WTF?!

Funny though, that e.g. Mahle has procedure for break in. Stating using break in oil as well as not running full load.. For the reason that the rings need to be adapted to the honed walls. Maybe your sub supplier of pistons for your race engines have one as well, what pistons do you use?

The comparison is not to be taking as 1 : 1. I'm puzzled why I need to write this. It was used as an example that almost all moving mechanical things need to adapt from new to their proper use to fit their calculated properties.

Keep your eye on the topic at hand. I don't think anyone here has stated that ELECTRONICS need break in. A speaker driver is an electro mechanical device. It has a voice coil and moving parts. Moving parts need break in in varying degree. That degree is sufficiently large IR to woofers that it can be audible and easily measured, which you can see in the links I have posted earlier.

Keep your eye on the ball and have a nice day. Racing is fun.

 

[Zapper]

Since we are talking about cars, I was told that tyres also have "burn in". Every time I get new tyres fitted, I am told to be careful for a few hundred km because new tyres do not grip as well. I assumed it was to do with compounds in the rubber that need to be worn off by the road. I don't know if this is true.

New tires have a mold release compound on them to make them slippery enough to be extracted from the mold. This reduces road grip until it gets worn off.

 

[cavedriver]

I wouldn't be making any generalizations like "all break-in is imaginary". Amir tested one speaker, and he's limited by the precision of the testing method (granted fairly fine resolution and to the limits of what the Klippel currently is used for). In my example it was an old driver that sat on the shelf for a long time. Who's to say what glue or materials are used in every speaker's spider and surround? Also, we don't know what, if any, run-in was done at the factory for the speaker Amir tested. I'm not saying I believe that most speakers have any break-in, only that it appears that it is unlikely that most speakers have break-in. We should all go back to our armchairs until more testing and data is done. I'm certainly not going to assume that break-in is necessary because I never would without evidence, but I'm also scientific enough to realize we do not (yet) have proof that break-in has no effect.

As a side note, I've over-amped a couple speakers over the years. Cheap speakers can show dramatic failures, but what happens to high quality drivers when they get over-driven? It could be elucidating on the sensitivity of the Klippel to try over-driving a couple drivers and see what happens first- does the speaker fail audibly or visibly (damage to back of voice coil for example) first or does the Klippel detect a difference in performance? What other kinds of defects can a Klippel detect? A tear in a cone? Damage a speaker on purpose and find the point where we can measure it...

 

[Rottmannash]

New tires have a mold release compound on them to make them slippery enough to be extracted from the mold. This reduces road grip until it gets worn off.

I can confirm that from experience when trying to go fast on brand new motorcycle tires

 

[YSC]

I wouldn't be making any generalizations like "all break-in is imaginary". Amir tested one speaker, and he's limited by the precision of the testing method (granted fairly fine resolution and to the limits of what the Klippel currently is used for). In my example it was an old driver that sat on the shelf for a long time. Who's to say what glue or materials are used in every speaker's spider and surround? Also, we don't know what, if any, run-in was done at the factory for the speaker Amir tested. I'm not saying I believe that most speakers have any break-in, only that it appears that it is unlikely that most speakers have break-in. We should all go back to our armchairs until more testing and data is done. I'm certainly not going to assume that break-in is necessary because I never would without evidence, but I'm also scientific enough to realize we do not (yet) have proof that break-in has no effect.

As a side note, I've over-amped a couple speakers over the years. Cheap speakers can show dramatic failures, but what happens to high quality drivers when they get over-driven? It could be elucidating on the sensitivity of the Klippel to try over-driving a couple drivers and see what happens first- does the speaker fail audibly or visibly (damage to back of voice coil for example) first or does the Klippel detect a difference in performance? What other kinds of defects can a Klippel detect? A tear in a cone? Damage a speaker on purpose and find the point where we can measure it...

I am pretty sure if any of those damages especially if coil is damaged it will show up as great FR deviation and distortions, as in the Behringer speaker he tested. Klippel is sensitive enough to detect the tiny speaker variations in the range our ears can't percieve, as in most measuring equipment nowadays, if the break in change is so minimal it can't be detected by a calibrated mic, it is practically non-exist as our ears won't remotely be able to detect that subtle change.