New speaker "playing in" period?

[Phil Starr]

Thanks Stevie, and thanks Alex for your data. Stevie I looked at your earlier data, where CMS changed by 21%. I then tried varying just CMS by 21% for a couple of drivers in winisd and guess what, predicted changes in bass response were less than 0.1dB at any frequency above f3 (that's the cut off frequency for any non-nerds still following). This pretty much supports your argument that we wouldn't hear these changes. Dickason is giving lower figures for the changes so obviously there would be less chance for the sound to be noticeably different.

Alex, your data is really interesting, especially in terms of trusting measurements, I would guess humidity is another factor especially with an absorbent paper cone. Are you saying that breaking in a speaker could be more important for higher frequencies than for simple things like box alignment?

I've repaired a lot of cabs over the years, one of the things I've noticed is that old speaker cones are lighter in colour and have a more matte surface than new cones even of the same model. If surrounds or dust caps come away they usually come away with fibres from the surface layer of paper attached. Clearly the bonding between the fibres that make up the cone are breaking down over time. Given that most of the higher frequencies we hear from a speaker are above the frequency where the cone starts to flex then I would expect the mid/highs to change over time changing the tonal balance in consequence.

[lurksalot]

Hmmm , maybe there is more to this, maybe the drivers are much cleaner nowadays, I remember earlier days when gigs were full of an acrid ,pungent, thick sticky atmoshere of nicotene , for every thump that loosened the tone , there must have been a half decent layer of crud to stiffen it back up again ,






But I'll get my coat and comfy shoes.

[R Baer]

[quote name='garythebass' timestamp='1355320740' post='1896884'] ...I think it's a bit unfair to accuse Bill, Alex or Mr Baer of trying to push their products, since none of them, to my knowledge, is offering a break-in service or selling sine-waves/test equipment. They are merely giving their opinion on what they believe will benefit us if we invest in new gear. If break-in is just 'snake oil', no-one is hurt and no-one loses out...[/quote]

Thank you for your understanding. I don't quite understand those who are saying we are pushing this, or that, or that this is all just marketing hype by a manufacturer to sell cabinets. I see no marketing benefit to telling our customers our cabs go through a break-in period. As we don't sell anything to accomplish this, there is certainly no money to be made from doing so. In fact, we don't recommend doing anything other than simply playing your cabinet to break it in. The OP asked for opinions, so I gave him mine based on my experience with the drivers we use in our cabs. If I didn't absolutely believe that the cabinet's tone changes after break-in, then what could I possibly have to gain by telling my customers they do? At this point, this thread just reminds me of the Monty Python argument sketch.

[url="http://www.youtube.com/watch?v=kQFKtI6gn9Y"]http://www.youtube.com/watch?v=kQFKtI6gn9Y[/url]

Edited December 13, 2012 by R Baer

[4 Strings]

[quote name='LawrenceH' timestamp='1355330905' post='1897066'] Larry Graham is outside the operational parameters of the model. MK v Flea. Gun to head. If you don't answer hell is an eternity of whichever one you don't want it to be most... [/quote]

MK on anything, through anything every time.

[Big_Stu]

[quote name='gjones' timestamp='1355328056' post='1896999']Is this one still going? It must be a record![/quote]

...... and so it should be; vinyl is always best - it's been proven in another thread!

[LawrenceH]

[quote name='Big_Stu' timestamp='1355399774' post='1897820']
...... and so it should be; vinyl is always best - it's been proven in another thread!
[/quote]
Oh damn, I forgot to put that in! MK is on CD, Flea on 1/4 inch tape.

Phil, Stevie - just playing around with sims I found more obvious differences with Cms in some drivers than others, but was still varying it by a factor of at least 2 - very much depends on the degree to which materials will change in the real world (and that kind of break in would probably be effectively over after a few seconds!), but overall it's intuitively surprising (to me) how insensitive performance is to that fundamental parameter. Rms variation only appears in the equation for one derived parameter - Qms - so how mechanical resistance changes over time would be interesting.

Just thinking out loud, it might be easier to reconcile reports of the low audibility of mid-range/treble effects with data like Alex's by considering that a lot of the changes would be at frequencies dominated by non-pistonic effects. Many drivers in-cab will be crossed below this point so raw driver response is not so relevant, also PA and definitely bass cab drivers are often asked to work higher than ideal for crossing, so manufacturers work more on fine-tuning behaviour higher up for these via more complex cone behaviour.

[alexclaber]

[quote name='LawrenceH' timestamp='1355401158' post='1897837']Just thinking out loud, it might be easier to reconcile reports of the low audibility of mid-range/treble effects with data like Alex's by considering that a lot of the changes would be at frequencies dominated by non-pistonic effects. Many drivers in-cab will be crossed below this point so raw driver response is not so relevant, also PA and definitely bass cab drivers are often asked to work higher than ideal for crossing, so manufacturers work more on fine-tuning behaviour higher up for these via more complex cone behaviour...[/quote]

The list of bass cabs where the woofers have any kind of crossover on them is quite a short one (Baer, Audiokinesis, some Barefaced, some Bergantino, anything else?) - the vast majority are running full-range. If we could run all our woofers full-range and get the performance we want then I would - big inductors are annoying components whilst passive crossovers and hot voice coils aren't the best combination.

[Ba55me15ter]

Can we all just stop distracting Alex please so he can get on with making my S12T.

Thank you.

[LawrenceH]

[quote name='alexclaber' timestamp='1355407139' post='1897985']
The list of bass cabs where the woofers have any kind of crossover on them is quite a short one (Baer, Audiokinesis, some Barefaced, some Bergantino, anything else?) - the vast majority are running full-range. If we could run all our woofers full-range and get the performance we want then I would - big inductors are annoying components whilst passive crossovers and hot voice coils aren't the best combination.
[/quote]

Yep I think we're well aware of this, and it was kind of my point - I'd think the contribution of bass cabs to the world of high fidelity testing has historically been fairly minimal! Hence you'd expect it might be more audible in bass cab scenarios simply because they ask more of the woofer - even if they cross it's usually too high for 'hifi'.

[Mr. Foxen]

[quote name='alexclaber' timestamp='1355407139' post='1897985']
The list of bass cabs where the woofers have any kind of crossover on them is quite a short one (Baer, Audiokinesis, some Barefaced, some Bergantino, anything else?)
[/quote]

The Peaveys with the 18s and 8" mids I think have a proper crossover. also the Ampeg isolvent, or whichever the one that is three way that Vic Wooten used/endorsed at one point?

[pete.young]

[quote name='alexclaber' timestamp='1355407139' post='1897985']
The list of bass cabs where the woofers have any kind of crossover on them is quite a short one (Baer, Audiokinesis, some Barefaced, some Bergantino, anything else?)
[/quote]

My EA VL110's have a 3-way crossover. I don't know whether the more recent EA cabs do though.

[stevie]

[quote name='alexclaber' timestamp='1355317189' post='1896794']
The attached plots are the same driver, the first measured in the summer, the second measured in the winter - ignore the LF stuff because it wasn't set up for that, it's a midrange/treble response measurement. The lower temperature changes the cone and the suspension stiffness - and look what that does to the frequency response curve!
[/quote]

Alex, thanks first of all for staying with this and for the measurements. I know we have diametrically opposed views on this issue (at the moment) but that doesn’t mean we cannot discuss the facts.

When you’re trying to figure out a puzzle like this one, it helps if you keep the variables to a minimum. Unfortunately, these curves add another variable – temperature. I appreciate you’re trying to show that stiffening the surround effects the frequency response of the speaker. But dropping the temperature by 10 degrees (was the ambient temperature 8 degrees?) not only affects the suspension, it affects everything. The voice coil resistance and inductance will drop as the temperature drops, the VC gap will change, the stiffness of the cone will change. Driver fs can rise by as much as 75 - 80 percent - compared with the 10 to 20 percent difference we see after break-in.

So, in some ways this is a bit of a strawman, in that you are proving something that nobody is contesting: everybody knows that varying the temperature of a loudspeaker changes its performance.

Then there is the matter of whether the differences shown are actually audible. It would be more useful to concentrate on the LF end because the data is easier to obtain and because this is where people are claiming to hear noticeable differences. Also, anyone on this forum with a copy of winSD who wishes to do so can plug the figures in and verify them, as I see Phil and Lawrence have already done.

[Phil Starr]

I'd add my thanks to Alex, it opens another topic for debate, perhaps. It could be relevant however.

My problem is that I've heard the changes in critical listening tests, and more than once. I fully accept Stevie's arguments about objectivity, I taught A level students about double blind testing and statistical significance for years. I know how easy it is to hear something that isn't there but for me the effect wasn't insignificant so I still feel there is something to explain. 20% changes in compliance don't do it, Though I might have a go at 20% changes with a wider range of speakers in winISD.

It may be that what I heard were changes in higher frequencies than I thought, Alex is showing the possibility that the flexibility of the cone changes with temperature and time and 'breaking in' a speaker may be more about changes in the compliance of the cone than changes in the suspension.

There's something here that I, for one, don't quite understand. I'm expecting someone can come up with something I've missed but solving the puzzle is interesting and may lead to some new understanding. It could be that none of us know. That possibility is why we get so cross with people who just contradict with no evidence. As Monty Python said argument isn't just contradiction.

Edited December 18, 2012 by Phil Starr

[TimR]

It's a mechanical device. Moving parts wear. In the same way that strings loose elasticity over time so do speakers.

Even if it is the high frequencies that are affected, we all know that it's the highs that define the lows. Bass is bass, what makes bass 'rumbly', 'tight' or a whole host of other fluffy descriptions is the presence and amount of high frequency.

My dad had a pair of celestion PA speakers that must have been 30years old. They sounded very wooly, no topend definition at all. We swapped them with new drivers and they sounded different.

The sound is going to change over time. We all accept that. The question is whether 10hours is noticable.

30mins is noticeable with my strings but after a year they're as dead as they're going to get. I guess the real question is how long do speakers take to stabilise into that flat part of the slope.

Edited December 19, 2012 by TimR

[4 Strings]

[quote name='Phil Starr' timestamp='1355823195' post='1903064']
I'd add my thanks to Alex, it opens another topic for debate, perhaps. It could be relevant however.

My problem is that I've heard the changes in critical listening tests, and more than once. I fully accept Stevie's arguments about objectivity, I taught A level students about double blind testing and statistical significance for years. I know how easy it is to hear something that isn't there but for me the effect wasn't insignificant so I still feel there is something to explain. 20% changes in compliance don't do it, Though I might have a go at 20% changes with a wider range of speakers in winISD.

It may be that what I heard were changes in higher frequencies than I thought, Alex is showing the possibility that the flexibility of the cone changes with temperature and time and 'breaking in' a speaker may be more about changes in the compliance of the cone than changes in the suspension.

There's something here that I, for one, don't quite understand. I'm expecting someone can come up with something I've missed but solving the puzzle is interesting and may lead to some new understanding. It could be that none of us know. That possibility is why we get so cross with people who just contradict with no evidence. As Monty Python said argument isn't just contradiction.
[/quote]

I think this is where I am, too (a little confused!). I have no evidence apart from my own anecdotal, I can respect that from the experience of likes of Alex and Maurice, and also the apparently opposing view presented from published articles by leading lights in the field. I also feel that the changes in my speakers were more than subtle and insignificant but I can offer no explanation when confronted with measurements.

You could say that measurement is me playing the same notes as Bernard Edwards in exactly the same way and so must sound like him, I clearly don't (no matter how hard I try!). Speakers don't develop 'feel' as they get used, so what is it?

[Bill Fitzmaurice]

[quote name='4 Strings' timestamp='1355912277' post='1904223']
I have no evidence apart from my own anecdotal, I can respect that from the experience of likes of Alex and Maurice, and also the apparently opposing view presented from published articles by leading lights in the field.
[/quote]Your own anecdotal can be just as vaild as some 'leading lights'. Take Vance, for example. For many years and editions of his book he espoused the notion that stuffing a sealed cabinet with damping duplicated the effect of a larger cabinet. He was wrong. He fell into the trap of accepting someone else's data and opinion at face value without confirmation, in this case that of Tom Nousaine, and Tom's conclusion was erroneous due to his having used incomplete data to arrive at it. I didn't accept Tom's conclusions without confirming them, and I found them incorrect. So have a number of other sources, and in his latest edition of his book Vance has revised his advise on the subject. The lesson that should be learned is that no source is infallable, and if you think something they say may not be spot on don't hesitate to confirm or disprove it for yourself. One's own anecdotal experience can be the first step in that process.

[Phil Starr]

[quote name='Bill Fitzmaurice' timestamp='1355924143' post='1904527']
The lesson that should be learned is that no source is infallable, and if you think something they say may not be spot on don't hesitate to confirm or disprove it for yourself. One's own anecdotal experience can be the first step in that process.
[/quote]

[quote name='4 Strings' timestamp='1355912277' post='1904223']
I think this is where I am, too (a little confused!). I have no evidence apart from my own anecdotal, I also feel that the changes in my speakers were more than subtle and insignificant but I can offer no explanation when confronted with measurements.
[/quote]
Bill is right of course, we should always be sceptical and just putting numbers to something doesn't prove anything.

The problem is that at the same time everything Stevie said about how observations are made and how the expectations of the observer affect what is observed are also true. Listening tests on speakers are notoriously unreliable and we know that we are all unreliable witnesses and see and hear what we want to see sometimes. I'm in the camp that believes it hears speakers 'break in' but I have no data and am left wishing I had taken measurements.

The way to resolve this though is in the science, to take measurements, say how you took them and let other people check them.

The problem with giving advice in these fora is that there are things we pretty much know about speaker design and other things which are still to be resolved, like stuffing cabs and breaking in. Most people who ask questions want a simple answer: can I use this speaker in this box? Can I run four of these speakers off this amp? Sometimes the answer isn't simple or we can only answer it with the benefit of experience rather than sound theory. What is the expert to do then? Personally I hedge my answers with 'could', 'maybe' 'perhaps' type words and hope the OP notices that the advice comes with a health warning.

I think the idea of breaking in a speaker isn't so much confusing as one we cannot be certain of. If someone has the killer data they haven't pointed to it yet.

[Jus Lukin]

-

Edited February 16, 2022 by Jus Lukin

[ShergoldSnickers]

It's just occurred to me that when I bought my Hi-Fi speakers (Epos ES14) in the early 90s, they didn't sound right at first. They were a bit bass light and slightly harsh, very different from a previous audition of a well used pair. After a few hours they did develop more of a full bass end and the treble smoothed out also.

I had previously been in contact with the person who designed them - a Robin Marshall - who also designed speakers for Monitor Audio and Mordaunt Short, so I asked him about this. I was told that the bass/mid driver takes a little time to settle in, but playing at reasonable levels and using music with good kick drum content would sort it. If I remember correctly, he also stated that the treble driver will sound harsh from new, but also 'loosens up'. The speaker drive units were actually designed by Robin Marshall and made to his specs - including as much smooth natural treble roll-off on the bass-mid driver as possible, the crossover being a capacitor, getting round the need for a more complex cross-over. I can only assume he was intimately knowledgeable about the drive units he'd designed, and that he knew how they would function from new.

OK it could all be complete nonsense, but I heard the effect before I was told it existed, and was given what seemed like a reasonable explanation. Anecdotal granted, but I thought I'd bung it in nontheless.

[Jus Lukin]

-

Edited February 16, 2022 by Jus Lukin

[stevie]

[quote name='Bill Fitzmaurice' timestamp='1355924143' post='1904527']
Your own anecdotal can be just as vaild as some 'leading lights'. Take Vance, for example. For many years and editions of his book he espoused the notion that stuffing a sealed cabinet with damping duplicated the effect of a larger cabinet. He was wrong. He fell into the trap of accepting someone else's data and opinion at face value without confirmation, in this case that of Tom Nousaine, and Tom's conclusion was erroneous due to his having used incomplete data to arrive at it. I didn't accept Tom's conclusions without confirming them, and I found them incorrect. So have a number of other sources, and in his latest edition of his book Vance has revised his advise on the subject. The lesson that should be learned is that no source is infallable, and if you think something they say may not be spot on don't hesitate to confirm or disprove it for yourself. One's own anecdotal experience can be the first step in that process.
[/quote]

Scientists [i]will[/i] change their minds when presented with new and convincing evidence. Theories persist until a better one is proposed, reviewed and accepted. Given that the Loudspeaker Cookbook has been in print in its various editions for 25 years, it is hardly surprising to find that one piece of information has changed.

The fact that this expert has revised his opinion in the light of new evidence makes him more credible, not less, but I don’t think he has ever claimed to be infallible.

[Phil Starr]

[quote name='andyjingram' timestamp='1356006348' post='1905539']

Perception is fallible, but we can't put everything we notice in the world down to preconceived notions or suggestion.

A very thorough test of multiple speakers by multiple examiners providing repeatable results would be the only way to truly prove any of this, but that costs time and money. Unike testing compounds for big pharma, the results would be very unlikely to make anyone any real money, so I can't see that strict enough science will ever be applied to get the kind of results (for or against) that we might like to see here.
[/quote]
Hi Andy, I pretty much agree but in practical terms this is low hanging fruit. It's the sort of project I'd have asked A level students to do. We already know how big a change in frequency response needs to be to be noticeable, so all we need to do is show a change in frequency resonse of that size. Several people here have gear to measure frequency response at varying degrees of sophistication and some, like Alex and BFM must do this regularly as part of their design process. As well as frequency responses we have a well worked out model (Thiele/Small) of the behaviour of speakers at low frequencies and can measure the TS parameters at home.

At the moment there is no objective evidence to suggest that 'breaking in' happens and is audible, at least none here. It may be that this evidence exists and will emerge or that someone will do some tests which,whilst not being conclusive, will show that at least one speaker in one test showed a measurable change in frequency response with use.

Stevie may be right and this is a bit of folklore passed down without much questioning but an absence of data doesn't prove anything. I'm curious as to the answer.

[Mr. Foxen]

I bet BFM has measured worn out speakers and has data to show a noticeable change in response. Shame that Acme guy wants the old speakers back as otherwise Alexclaber would have his work out woofers to play with.