I've recently got a new pair of AKG 701s...

Various 'authorities' on the net recommend 'burning-in' for 300(!) hours. Others say it makes little or no difference.

Surely this can be proved conclusively - once and for all - by some boffin or manufacturer?

Simply measure any decent cans' response when brand new, then after burning in. Check for a measurable difference, and evaluate if that difference is in any way beneficial.

Has this been done?

Quote Evie McCreevie:

---

Surely this can be proved conclusively - once and for all - by some boffin or manufacturer?

---

Yes... though more difficult to be truly scientific about it: how to you blind test the same pair of cans before and after burning in? Maybe the playback level has a bearing on it; or the frequency content of the material played through them...

Certainly my HD650s got subjectively better over the first few months.

I burned in my K701s and I'm absolutely convinced that it made a difference for the better. I also googled this extensively and never came across any tests that showed that burning changes the sound. In the end I decided that it wasn't a lot of effort so why not...

/erol

Edited by ezza (21/04/11 03:10 PM)

Some drivers whether in headphones or loudspeakers do require time to reach their optimal performance. I know Dynaudio Acoustics used to suggest a "wearing in" period.(They may still do)

I do not think it takes too larger stretch of the imagination to believe that moving parts may require some regular movement before the materials settle down and perform optimally or at least in a more stable manner.

cheers

SafeandSound Mastering

--------------------
Mastering online mastering

Quote Evie McCreevie:

---

I've recently got a new pair of AKG 701s...

Various 'authorities' on the net recommend 'burning-in' for 300(!) hours. Others say it makes little or no difference.

Surely this can be proved conclusively - once and for all - by some boffin or manufacturer?

Simply measure any decent cans' response when brand new, then after burning in. Check for a measurable difference, and evaluate if that difference is in any way beneficial.

Has this been done?

---

If "burning in" was accepted science it would be ... well ... accepted science. The fact that it isn't may suggest an answer to you :-)

There are no "accurate" microphones, speakers or headphones. Suggesting that a "burning in" period will mellow such tools may reduce any tendency to want to exchange them on the day of purchase for sounding "different".

Subjectively, of course, the difference between "burning in" and "getting used to" is impossible to detect!

There's some point in burning in active devices simply as part of the testing process. If it lasts the first week, it's likely to be a good 'un. Some manufacturers find it economic not to test but just to replace early failures without question. If the failure rate is low enough, this is not necessarily immoral.

It depends what type of lighter fuel you use for the burning. Some people favour butane over propane as it has greater mass and helps to give deeper basses and a more airy top end.

--------------------
~~~ A weasel hath not such a deal of spleen as you are tossed with! www.feline1.co.uk ~~~

Quote Exalted Wombat:

---

If "burning in" was accepted science it would be ... well ... accepted science. The fact that it isn't may suggest an answer to you :-)

---

Except that this isn't a binary scenario. Scientific testing gives you various possibilities: something may be proven to be possible or impossible; it may be demonstrated to be probable or improbable; or of course the results may be entirely inconclusive, whether due to lack of evidence or difficulty in interpreting the results. What you're saying is that one of the above hasn't been shown to be the case... but that still leaves a lot of possibilities

I'm sure everyone has experienced the 'burning in' process involved after the purchase of a new pair of shoes. When you first put them on they feel stiff and inflexible, yet after wearing them for a while they soften and become much more comfortable.

Exactly the same thing happens with a lot of different materials, including some of those used for making loudspeakers and headphone drivers. This is well known and documented in the professional and academic literaure.

The characteristics of the fabrics and especially the glues and supporting flexible surrounds often change during the early period of use, before settling down to a stable state for the rest of the product's lifetime, before eventual failure.

These changes in characteristics can be very subtle, or they can be surprisingly significant... and whether you can hear it or not depends partly on the listener's hearing accuity, but much more so on the actual product design.

If some parameter of the material -- such as its stiffness or self-damping -- plays a critical role in the overall performance (resonance tuning, say) of the product, then that performance will change audibly as the material 'beds in'.

Some designs require and rely on very tight parameter specifications to deliver the specified performance. others are far less critical... and that's why not all products reveal an audible burn-in period.

My personal experience with AKG K701s is that their performance does 'mature' during the first few hours of use -- but nothing like 300 hours!

Hugh

--------------------
Technical Editor, Sound On Sound

Quote Hugh Robjohns:

---

My personal experience with AKG K701s is that their performance does 'mature' during the first few hours of use -- but nothing like 300 hours!

---

+1
I just listened to my pair of 702s straight out of the box and there was a noticeable improvement in bass extension over the first hour or two.

So I left them running at a loudish volume overnight to see if there would be any change. I'd say there was some difference between the 5hr mark and 15hr mark (from when I left them overnight) *maybe* a very little again at the 25hr mark (left for a second night) but not really very noticeable.

They are now well past the 300hr milestone and I'd be extremely hard pressed to say there is any difference between now and at 25hrs.

Hope this rambling helps in any way whatsoever.

Quote Evie McCreevie:

---

I've recently got a new pair of AKG 701s...

Various 'authorities' on the net recommend 'burning-in' for 300(!) hours. Others say it makes little or no difference.

Surely this can be proved conclusively - once and for all - by some boffin or manufacturer?

Simply measure any decent cans' response when brand new, then after burning in. Check for a measurable difference, and evaluate if that difference is in any way beneficial.

Has this been done?

---

I have various things from various manufacturers.

But with the K701 it seems that the consensus is that it needs a very long burning in time and I think about 500 hours is the norm for these.

I know 0VU had (has) a pair and I am sure he said that they needed a very long burn-in; were pretty nasty at the start and great when finished.

--------------------
John - Sound-Link ProAudio
President - Federation Internationale des Chasseurs de Sons

Quote John Willett:

---

Quote Evie McCreevie:

---

I've recently got a new pair of AKG 701s...

Various 'authorities' on the net recommend 'burning-in' for 300(!) hours. Others say it makes little or no difference.

Surely this can be proved conclusively - once and for all - by some boffin or manufacturer?

Simply measure any decent cans' response when brand new, then after burning in. Check for a measurable difference, and evaluate if that difference is in any way beneficial.

Has this been done?

---

I have various things from various manufacturers.

But with the K701 it seems that the consensus is that it needs a very long burning in time and I think about 500 hours is the norm for these.

I know 0VU had (has) a pair and I am sure he said that they needed a very long burn-in; were pretty nasty at the start and great when finished.

---

Burn in: proven. For the AKG701 there's a definitely settling in and deepening of the bass response and improvement of the general frequency balance.

500 hours? Mmmm... I'm not sure I agree with 2 guys (JW and 0VU) I respect immensely: sorry but the major differences are gone pretty quickly - say 50 hours tops playing my iTunes library loud and placed around the box.

Reg

Quote feline1:

---

It depends what type of lighter fuel you use for the burning. Some people favour butane over propane as it has greater mass and helps to give deeper basses and a more airy top end.

---

Sure that wasn't what Hendrix used...



>

--------------------
planet nine
lincoln, uk.

Quote RegressiveRock:

---

Quote John Willett:

---

Quote Evie McCreevie:

---

I've recently got a new pair of AKG 701s...

Various 'authorities' on the net recommend 'burning-in' for 300(!) hours. Others say it makes little or no difference.

Surely this can be proved conclusively - once and for all - by some boffin or manufacturer?

Simply measure any decent cans' response when brand new, then after burning in. Check for a measurable difference, and evaluate if that difference is in any way beneficial.

Has this been done?

---

I have various things from various manufacturers.

But with the K701 it seems that the consensus is that it needs a very long burning in time and I think about 500 hours is the norm for these.

I know 0VU had (has) a pair and I am sure he said that they needed a very long burn-in; were pretty nasty at the start and great when finished.

---

Burn in: proven. For the AKG701 there's a definitely settling in and deepening of the bass response and improvement of the general frequency balance.

500 hours? Mmmm... I'm not sure I agree with 2 guys (JW and 0VU) I respect immensely: sorry but the major differences are gone pretty quickly - say 50 hours tops playing my iTunes library loud and placed around the box.

Reg

---

Normally I agree that about 48 hours is fine.

But for the K701 I have heard many many people saying that they need a very long burning in time and 500 hours is what has been said by many.

--------------------
John - Sound-Link ProAudio
President - Federation Internationale des Chasseurs de Sons

Quote John Willett:

---

I have various things from various manufacturers.

But with the K701 it seems that the consensus is that it needs a very long burning in time and I think about 500 hours is the norm for these.

---

500 hours? shurely shome mishtake? That's 21 days of solid playing(!) Blimey, pleased I went with the DT880s, now. They did need some burning in, mind.

Quote John Willett:

---

[Normally I agree that about 48 hours is fine.

But for the K701 I have heard many people saying that they need a very long burning in time and 500 hours is what has been said by many.

---

Mine seemed to settle in after a couple of weeks of ‘normal’ use (50+ hours-ish?). The bass deepened and the front-to-back imaging increased.

I might be goaded into believing that they continued to improve beyond this period, but it could be a combination of wishful thinking and familiarity.

When my 701s give up the ghost I’m straight back for another pair with no hesitation at all.

--------------------
An Eagle for an Emperor, A Kestrel for a Knave.

This is what 0VU said on the matter in this thread back in 2009:

Quote:

---

I'd give them at least 100 hours before trying to do anything with them as before that they're actually pretty nasty sounding and very disappointingly harsh and bass light. I've found with all the pairs I've bought that there's quite a marked change at about 100 hours or so. They then go on steadily but noticeably improving over the next 100 hours or so, and then more subtly for a while longer. After 300 hours any change is slow, very subtle and probably due as much to wear and tear and normal aging as to 'running in'.

If you can bear the wait, I'd say leave them alone for 200 hours, and maybe up to about 300 if you can stand the suspense They should, however, be quite usable as a reference after about 200 hours. Just don't try to use them straight away as you'll wonder why you bought them!

Curiously, the K702s seem to need even more running in. I've only got one pair so far but they needed about 200-250 hours to pass the first big change point and didn't settle in to the K701s 200 hour sound until past 300 hours. That is however, only based upon one pair, whereas the K701 comments are based upon nine or ten pairs that I've bought for myself or other people so far.

Incidentally, the K702s are even better than the 701s Not a huge leap; more an incremental improvement but everything is just a little bit more 'refined'/'developed'/improved/etc. Hard to describe; they're just that bit more 'special'. And a less ...er... obvious colour too


700-800 hours sounds pretty extreme to me. I can't reliably discern any change between pairs once they pass 300-400 hours (I've had the luxury of having several pairs here and being able to compare them at different run times). The K701s (and now K702s) seem to need more settling time than any other piece of gear I've ever bought. Certainly the Sennheisers I used before them (and still have and use from time to time - HD580/600/65/25) only need a fraction of that to hit their stride; I'd say 20-50 hours (ish) and they're pretty much settled.


The K701s do seem to benefit more than the Sennheisers from a good powerful amp. It's odd in that I find that in some ways they're more forgiving than Sennheiser HD600/650s of what they're driven by (i.e. they sound better than the Sennheisers when plugged into a fairly average/crap headphone socket on a piece of gear, even though the HD600/650 are probably easier to drive and need less power to sound at their best) but when given a good powerful amp (and they do like something with plenty of power) the improvement in the K701s is greater than I get from putting the Sennheisers on a better amp.

---

So 0VU recommends around a fortnight of constant running to achieve the optimum sound quality... and while that seems rather more than my own experiences I gladly defer to his opinion as he certainly has better ears than me.

Hugh

--------------------
Technical Editor, Sound On Sound

It is a little bit amusing that when someone from hi-fi world says they can hear a difference they are told to back it up by measurements or double blind tests.

Yes most of the headphones I have used have got better as they break in, not sure about some Ultimate Ears (armature) or some old curl-up Yamahas- they stayed crap. Much as turntable cartridges and loudspeakers do.

Does something like this help?

http://www.gr-research.com/myths.htm

http://www.head-fi.org/forum/thread/482386/building-a-headphone-measuremen t-lab/180

(there is a link about 4 post in on this page- it links to a pdf but the link is very long)

my experience is the same as that of 0Vu... i usually whack em on a football, and run them for a week in a cupboard out of the way....

i can reliably tell the difference between a NEW set, and a run in "new" set....

without being told which is which.

i know any number of other people that can also do the same....

0VU, i'm pretty sure, doesn't need to A/B but can tell if they're run in just by picking them up and having a quick listen, the man has the longest audio memory i've ever encountered.

Nuff said by you all. I agree!!!

Headphone transducer burn in is a myth. All those 50 hour burn in sessions are a waste of time.

Who says so? Not me, Horst Werner from AKG

Quote:

---

From our experience and knowledge we cannot confirm that there is a burn in effect of the transducers taking place.

Normally the sound of headphones changes only over many years and then mainly caused by the ear pads (less low end since the ear pads get more densely by sweat etc.).

However, during the first hours of use of headphones, the ear pads - in the beginning a little stiff ... start to accommodate to the users ears and head and the sealing becomes better, as a result the bass can be increased a little, on the other hand the distance between the headphones and the ear may become closer, i.e. fewer air volume between ears and headphones is available and thus less bass.

Horst
AKG

---

So, you can wear in headphones (just like Hugh's shoes analogy), but you actually have to wear them, and it doesn't matter if you listen to anything or not. Probably you get a similar result if you put them on a football, or whatever.

Based on AKG's statement: blasting audio through phones left lying around overnight has no effect whatsoever. I guess this practice could be the origin of some of those '500 hour burn in' stories. I imagine a few people are diligently burning in their new headphones for weeks but rarely wearing them.


I was wondering why manufacturers don't simply burn in headphones for you - they could avoid all this hassle and confusion about burn in. I think the above statement from AKG is the explanation, and it's basically for the same reasons that manufacturers don't wear in shoes for you.

Dont burn em in
Stick them in the lower oven of the AGA
Cures most pro audio problems in my house.

--------------------
I am the Walrus.

Quote Axonaut:

---

Headphone transducer burn in is a myth. All those 50 hour burn in sessions are a waste of time.

Who says so? Not me, Horst Werner from AKG

Quote:

---

From our experience and knowledge we cannot confirm that there is a burn in effect of the transducers taking place.

Normally the sound of headphones changes only over many years and then mainly caused by the ear pads (less low end since the ear pads get more densely by sweat etc.).

However, during the first hours of use of headphones, the ear pads - in the beginning a little stiff ... start to accommodate to the users ears and head and the sealing becomes better, as a result the bass can be increased a little, on the other hand the distance between the headphones and the ear may become closer, i.e. fewer air volume between ears and headphones is available and thus less bass.

Horst
AKG

---

---

Thanks for that post Axonaut.

When starting this thread, I said:
"Various 'authorities' on the net recommend 'burning-in' for 300(!) hours. Others say it makes little or no difference."

Looks like we're back where we started!

Surely any significant difference between new and 'burned-in' cans would be measurable?

Any 'evidence' produced so far has been purely subjective.

Quote Evie McCreevie:

---

Thanks for that post Axonaut.

When starting this thread, I said:
"Various 'authorities' on the net recommend 'burning-in' for 300(!) hours. Others say it makes little or no difference."

Looks like we're back where we started!

Surely any significant difference between new and 'burned-in' cans would be measurable?

Any 'evidence' produced so far has been purely subjective.

---

Not really an answer, but here's a post that has it all... Apparently different viewpoints from two representatives of the same manufacturer (including a familiar name), a real test of speaker drivers demonstrating a change in response, etc...

http://www.head-fi.org/forum/thread/154481/burn-in-time-myth-or-fact

And when all is said and done, what are you going to do about it?

You get used to a new room, a new instrument, a new piece of equipment in various ways. So the process isn't completely one-sided!

Quote Axonaut:

---

Headphone transducer burn in is a myth. All those 50 hour burn in sessions are a waste of time.

Who says so? Not me, Horst Werner from AKG

Quote:

---

From our experience and knowledge we cannot confirm that there is a burn in effect of the transducers taking place.

Normally the sound of headphones changes only over many years and then mainly caused by the ear pads (less low end since the ear pads get more densely by sweat etc.).

However, during the first hours of use of headphones, the ear pads - in the beginning a little stiff ... start to accommodate to the users ears and head and the sealing becomes better, as a result the bass can be increased a little, on the other hand the distance between the headphones and the ear may become closer, i.e. fewer air volume between ears and headphones is available and thus less bass.

Horst
AKG

---

So, you can wear in headphones (just like Hugh's shoes analogy), but you actually have to wear them, and it doesn't matter if you listen to anything or not. Probably you get a similar result if you put them on a football, or whatever.

Based on AKG's statement: blasting audio through phones left lying around overnight has no effect whatsoever. I guess this practice could be the origin of some of those '500 hour burn in' stories. I imagine a few people are diligently burning in their new headphones for weeks but rarely wearing them.


I was wondering why manufacturers don't simply burn in headphones for you - they could avoid all this hassle and confusion about burn in. I think the above statement from AKG is the explanation, and it's basically for the same reasons that manufacturers don't wear in shoes for you.

---

But I have heard the opposite from the chief headphone designer at Sennheiser.

He recommended 48 hours of pink noise at normal listening levels.

He says it's due to the glue in the headphones settling into the final position.

--------------------
John - Sound-Link ProAudio
President - Federation Internationale des Chasseurs de Sons

As I said before, a lot of this depends on whether or not the design of the headphone (or loudspeaker) relies on one or more critical parameters of the driver to achieve the intended level of performance, and whether that or those parameter(s) vary in the initial hours of use.

It may also be that some manufacturers run longer driver acceptance and tolerance tests or in-house burn-in tests than others, and so subsequent owners experience more or less burn-in effects.

For these reasons I don't think you will ever find a single, universal answer. Some products do change (and hopefully improve) over a 'burn-in' period by the user, and some don't. The same is very much true for loudspeakers too. Some change and some don't. And equally, some manufacturers recommend it and some don't.

The reason why manufacturers don't do the burn-in themselves is entirely practical -- it takes resources including time and space which would inevitably result in higher prices. In a competitive world where the end user can perform this process more easily, it makes sense that the manufacturer hands this across.... and for the more sceptical it also gives them the facility to bounce back end user complaints with the 'try running them in for a few more hours' suggestion

Absolute testing of performance would be possible given a suitable test rig and a number of identical headphone sets with different burn-in periods... and one of the previous links in this thread did provide a site which had done precisely that -- and claimed measurable differences.

But the bottom line is... it really doesn't matter. All headphones will work fine out of the box. And if you are happy with the initial sound then there is no need to concern yourself with burn-in. It is also undoubtedly true that there will be a certain period of getting used to a new set of headphones...

For those that think a burn-in period is required, then burn your headphones in. It can't do any harm and if makes you feel better about things, then great.

No one is going to make life-critical decisions based on headphone (or speaker) performance, so really it doesn't matter. There are far more important things to concern ourselves with.

hugh


--------------------
Technical Editor, Sound On Sound

Quote Hugh Robjohns:

---

...No one is going to make life-critical decisions based on headphone (or speaker) performance, so really it doesn't matter. There are far more important things to concern ourselves with.

---

Hugh, with all due respect, that's an odd remark...

We know no one is going to make life-critical decisions based on ANYTHING discussed on this forum.

But I'd have thought knowing whether headphones are more accurate after burn-in (or not) would be of interest, even importance, to anyone involved in recording and mixing music.

Quote Evie McCreevie:

---

Surely this can be proved conclusively -

---

I'm not so sure it can.
Science hates mythology. But non the less, there is mythological truth. I think you may have found one Evie.
Perhaps 'burning in' is a myth. But that is ok in my book.

--------------------
.. is this thing on?

Quote Evie McCreevie:

---

But I'd have thought knowing whether headphones are more accurate after burn-in (or not) would be of interest, even importance, to anyone involved in recording and mixing music.

---

I'm not sure "accurate" is a useful concept for any sound transducer, particularly when coupled with a brain and ears!

It really can't be that difficult to check - someone, somewhere, sometime must buy more than one set of similar 'phones at the same time. So long as there is a reasonable consistency in sound as they come out of the box it can't be that difficult to stick one pair on pink noise for a couple of days and then see if they still sound the same? The sort of differences attributed to the K701s should be pretty obvious.

A.

--------------------
Andi, www.thedustbowl.net Mixing, Mastering, Audio Editing at The Dustbowl Audio

Quote Evie McCreevie:

---

Hugh, with all due respect, that's an odd remark...

---

Perhaps I was feeling a little odd yesterday!

Quote:

---

But I'd have thought knowing whether headphones are more accurate after burn-in (or not) would be of interest, even importance, to anyone involved in recording and mixing music.

---

Not really. It's just yet another distraction for those who like to worry about the gear rather than use it to make or record good music. Perhaps a sense of proportion would be a good idea here before people start disappearing up their own derrieres!

If you take two top and highly respected headphones -- let's say Sennheiser HD650 and AKG 701 -- they sound completely different to each other, yet both are revered as 'accurate' headphones. If you 'burn' them in for x hours they might sound marginally different from when they were new... but they still sound more different to each other.

And then if you go and move a microphone in front of a guitar a few inches the sound will be radically different, far and above any subtle change caused by running in a pair of headphones.

So really... what's important here?

Personally, I believe that some products do benefit from a running-in period. Some electro-acoustical products (headphones and speakers, primarily) -- but certainly not all -- do experience a change (usually an improvement) in bass extension, resolution, distortion or whatever, through a burn-in period which may be a few hours to many tens of hours. Where practical I will provide that burn-in time.

But... would my recordings or mixes suffer dramatically if I didn't allow that burn-in? No, of course not.

So, as I suggested before: if you feel a burn-in period is warranted then go for it. If you don't, then don't. It's the choice of the end user. Either way it really won't make a lot of difference to what they do: there are far more fundamental and audible things to worry about such as arrangement, room acoustics, mic position, mix balance, processing effects, and so on.

Bottom line: let's keep the notion of 'burning in' in perspective.

Hugh

--------------------
Technical Editor, Sound On Sound

Quote Hugh Robjohns:

---

Bottom line: let's keep the notion of 'burning in' in perspective.

---

+1 I didn't, and wouldn't, 'burn in' my K701s any more than I'd 'burn in' a new car's engine. I just used the darned things and noticed a (pleasing) difference over time.

I certainly wouldn't try to 'make' it happen!

--------------------
An Eagle for an Emperor, A Kestrel for a Knave.

We've spent almost 168 burn in hours just discussing the issue.

My problem comes when people say I listened to them and then I listened again 100 hours later and it sounded better. I thought a reliable A/B comparison needed to be a few seconds between the change over to be effective. So the only way to know is to compare new for 'part-worn' as some above have done. Which you aren't able to do. I wouldn't worry about it, just use them. Stick them playing in a cupboard if you want between sessions, can't do any harm really.

We have been here before with monitors.
All bollocks IMO because IF kit changed significantly over that period if time then the original specification is not worth the paper it is (barely these days!)written on.

Springs do not wear out/get weaker. They just break.

Dave.

Quote ef37a:

---

All bollocks IMO because IF kit changed significantly over that period if time then the original specification is not worth the paper it is (barely these days!)written on.

Springs do not wear out/get weaker. They just break.

---

You're welcome to your opinion, Dave, and I respect that even if I don't completely agree... but I feel the need to point out that your arguments hold no more water than those arguing the case for burning in.

Firstly, in my experience the specifications for products are generally derived from units that have been fully burned in.

And secondly, while springs made of metal don't usually change in their springyness, plenty of other springy bits of metal do. Different materials behave in different ways. A steel spring doesn't work-harden when it is flexed... but a piece of steel sheet certainly does. The properties depend on the detail composition of the material and the way it has been created or treated.

Nuff said...

hugh

--------------------
Technical Editor, Sound On Sound

Quote Hugh Robjohns:

---

derrieres!

---

Quote Hugh Robjohns:

---

Bottom

---

Care to tell us more about this fixation Hugh?

Quote ef37a:

---

Springs do not wear out/get weaker. They just break.

Dave.

---

Dave

how does that work then? Are they as likely to break on the first flex as they are on the billionth? If not, and if they don't wear-out, then why not. I think those springs have an expected life during which they will operate within spec, but they are still "wearing-out" which means that they are still changing from flex to flex. The trick is to use materials and design such that the wear and tear of normal use has the minimal impact on the operational spec of the item. Thus your spring may not become less "springy" but it is becoming more "brittle" with use.

A.

--------------------
Andi, www.thedustbowl.net Mixing, Mastering, Audio Editing at The Dustbowl Audio

Quote Andi:

---

Quote ef37a:

---

Springs do not wear out/get weaker. They just break.

Dave.

---

Dave

how does that work then? Are they as likely to break on the first flex as they are on the billionth? If not, and if they don't wear-out, then why not. I think those springs have an expected life during which they will operate within spec, but they are still "wearing-out" which means that they are still changing from flex to flex. The trick is to use materials and design such that the wear and tear of normal use has the minimal impact on the operational spec of the item. Thus your spring may not become less "springy" but it is becoming more "brittle" with use.

A.

---

Nope.

Provided the material is never stressed near its plastic point (and I think Hugh was playing a blind here and knew it!)springs really do last "forever".

When did you last hear of a valve spring breaking in an engine? There are thousands of centuries old clocks and guns that just keep working.

Or are we to suppose that speaker suspensions are not so well designed?

And IF burning in were true and I was paying 1000's for speakers I would expect them to come to me right!

Dave.

Quote ef37a:

---

Or are we to suppose that speaker suspensions are not so well designed?

---

I think it's safe to say they aren't made of tempered and hardened steel... and although I've saiud it before, different materials have different properties, characteristics and life cycles.

Quote:

---

And IF burning in were true and I was paying 1000's for speakers I would expect them to come to me right!

---

You would pay £8k (inc VAT) for a pair of PMC's IB2S monitor speakers, and I can guarantee you that even you would notice a significant improvement in character over a few hours of burning in! Specifically, the bass would change from sounding initially like a nasty cardboard box to a deep, smooth, wondefully neutral and clean bottom end.

But if you ask PMC very nicely they might burn them in for you before shipping... if they had the time and space. They usually do for review models

hugh

--------------------
Technical Editor, Sound On Sound

I have to agree. It's more about letting the materials get loose and settle than anything else. I mean we do it with cars and jeans right? Why not audio gear?

PS: I just blast Nirvana overnight. Works every time.

--------------------
noise cancelling headphones