Breaking in new sub-woofer?

[sacsking916 5,000+ posts]

i'd say listen to the mods. there is a reason they are mods. they know their stuff and they wont lie to you

that is not why they are mods. they are mods because they know how to be good mods, the knowledge they posess is just a benefit

 

[Falcons 5,000+ posts]

but most of them have been here long enough to learn a thing or two about car audio

 

[sacsking916 5,000+ posts]

but most of them have been here long enough to learn a thing or two about car audio

as i said, they are there cause goob picked them cause he can trust them and there judgement. the knowledge they posess is an added bonus.

 

[Falcons 5,000+ posts]

i know lol im not fighting with you im agreeing holmes

 

[pro-rabbit 5,000+ posts]

I understand what you are saying about added stress to the joint due to less suspension travel. But the problem with that idea is, once the suspension loosens up and allows higher suspension travel, that stress is still present (and largely the same) because the suspension is moving further, still applying the relatively same amount of stress on the glue joints. It would be equivalent to suggesting stiff suspension speakers with less cone excursion are more likely to break than speakers with looser suspension that have higher excursion potential.
Say you have 1000 watts on tap. When the sub is new, cone travel is (slightly) less. When the sub is older and suspension compliance loosens up, cone travel is (slightly) higher. When the suspension is stiffer, you are suggesting this adds more stress to the t-joint because the spider is trying to resist motion more. But, once the suspension loosens up, cone travel goes up, and even though the suspension is not as stiff as it use to be, stress on the t-joint (and spider landing joint) will be approximately the same, because even though the suspension is looser, its not 'stretching' further. Remember, that 1000 watts transfers a certain amount of energy to the speaker's suspension, regardless of suspension compliance.

Look at it another way. Say suspension compliance is 0. The cone will not move at all. Now we send that 1000 watts through the coil. NO suspension travel, none. Have we increased stress on the t-joint by having no suspension travel? Have we lowered the stress on it? Or is it approximately the same? 1000 watts creates a certain amount of 'work', so the answer is the stress will be similar.

Actually that would only be accurate if the travel before and after are close to the same. The drivers in which I am speaking of is not the case. There is a huge difference in moving less then 1" to moving over 3". I will have to see if I can come up with a video to explain this a bit better then I am doing.

It is highly typical from any "large motor" driver that uses cheap spiders. The triple joint can and will fail if the suspension is far to stiff and the suspension tries to move to far. Once the spider is broken down a bit the travel is then easier to obtain and less stress is actually on the joint.

Give me a bit to think of a good way to demonstrate what I'm trying to describe lol..It will help once I figure something out.

 

[audioholic 5,000+ posts]

Actually that would only be accurate if the travel before and after are close to the same. The drivers in which I am speaking of is not the case. There is a huge difference in moving less then 1" to moving over 3". I will have to see if I can come up with a video to explain this a bit better then I am doing.
It is highly typical from any "large motor" driver that uses cheap spiders. The triple joint can and will fail if the suspension is far to stiff and the suspension tries to move to far. Once the spider is broken down a bit the travel is then easier to obtain and less stress is actually on the joint.

Give me a bit to think of a good way to demonstrate what I'm trying to describe lol..It will help once I figure something out.

I understand what you are saying, but I think you are missing my point. Before and after the 'break-in' period, the enclosure doesn't change, and the wattage doesn't change (much, it will slightly due to changes in impedance rise), the only change is the change in suspension compliance. The spiders resist excursion (always trying to re-center the cone assembly) while also helping resist coil rock and misalignment. As the compliance of the spiders loosens up, common sense would suggest this means less stress on the glued joints holding these moving parts together (like the t-joint). But, since we know acoustic compliance and input power are (basically) the same, its easy to understand that cone excursion will and does increase. How much does it increase? It increases in an amount relative to how much the suspension loosens (obviously).

How much difference in cone travels is experienced before and after the break-in depends on how much the suspension resistance changes. The end result will be the suspension travels further, and to the point at which is displays the same amount of resistance as it did before the break-in period (again because the other two factors, power and enclosure size, have not changed). So since the newly looser suspension is moving further to display the same resistance for that given power and enclosure, resistance (and hence stress) on the joints holding those moving parts together will be the same.

In other words, say an imaginary suspension allows 1 inch of travel when its new and stiff. Once its broken in, its compliance is doubled, and travel is now 2 inches. Stress on the glue holding it all together will be approximately the same since the suspension is giving the same resistance at 1" pre-break-in and at 2" post-break-in. Will the stress be exactly the same? No. Things like power compression will alter power available somewhat, and the added friction from the components moving further will decrease that doubling of excursion somewhat, but stress on the joints holding it together wont be affected so directly by these factors and will remain roughly the same.

Hope that makes sense.

 

[pro-rabbit 5,000+ posts]

I understand fully what you are saying but I know from first hand tests the real world results. I seen how "pre break in" with low grade stiff spiders will cause the triple joint to fail and quickly. After break in the triple joint would not fail unless it was pushed far beyond the limits of the spider.(with a stiff suspension is not hard when many "customers" think they are meant to have a large amount of movement)

It may seem odd or illogical considering your knowledge base but I can assure you that it is 100% real. I can not go into much detail here, but I can PM you some of the test descriptions that were used and the results of each test. I can not get into great detail as I am not allowed to, but I think I could give you enough info to help understand what I'm trying to describe yet being to vague in the public to help my part of the conversation.

I understand the compliance in the idea of "stress" on the triple joint before/after "break in" and that they should be so close it should be negligible, and for the most part and with most companies they are indeed just that and if that part of the sub were to fail it would indeed be user error causing the failure. However, that is not entirely the whole situation and when considering materials and physical traits of said materials the amount of "stress" does change a great deal. Mind you this is only for the first few strokes of said suspension and after that the difference is as just as you describe and can be negated.

Again, this is not directed to any company what so ever and for the vast majority of the companies out there this is not an issue. Just a few companies that use cheap material and cheap resign on the spiders. No, if you(anyone) PM me I can not and will not give you a list of said companies. Just because I know which because of various tests with a wide array of companies does not mean that I am allowed(by contract) to discuss what brands or particulars were used in said tests.

And to be fair, I have worked with and for a wide array of companies not just the last one which happened to be more "publicly known" because of the forum.

The idea of "break in" has been and will almost always discuss the driver finally coming into what the company would consider optimal playing conditions. It does not in most cases mean you can not beat on the sub right away. Many companies do use is as a ploy to void warranty though. I do hope the last part of that statements changes in the near future.

 

[05trailblazer 10+ year member]

i know the answers to that.

 

[maljr1980 10+ year member]

i may be wrong but i always heard its so th voice coil can wear in a grove and doesnt come unseated, but i may be wrong

 

[hispls 5,000+ posts]

LOL. I think audioholic nailed it.

Really tough to disprove either since if you don't "break in" a woofer and it fails you can't then "break in" the same woofer and see if it fails since it's already broken.

 

[goingdef 10+ year member]

i may be wrong but i always heard its so th voice coil can wear in a grove and doesnt come unseated, but i may be wrong

If you need to wear in a groove with the VC you got bigger problems to worry about other then spider/glue joint stress!

 

[audioholic 5,000+ posts]

I understand fully what you are saying but I know from first hand tests the real world results. I seen how "pre break in" with low grade stiff spiders will cause the triple joint to fail and quickly. After break in the triple joint would not fail unless it was pushed far beyond the limits of the spider.(with a stiff suspension is not hard when many "customers" think they are meant to have a large amount of movement)
It may seem odd or illogical considering your knowledge base but I can assure you that it is 100% real. I can not go into much detail here, but I can PM you some of the test descriptions that were used and the results of each test. I can not get into great detail as I am not allowed to, but I think I could give you enough info to help understand what I'm trying to describe yet being to vague in the public to help my part of the conversation.

I understand the compliance in the idea of "stress" on the triple joint before/after "break in" and that they should be so close it should be negligible, and for the most part and with most companies they are indeed just that and if that part of the sub were to fail it would indeed be user error causing the failure. However, that is not entirely the whole situation and when considering materials and physical traits of said materials the amount of "stress" does change a great deal. Mind you this is only for the first few strokes of said suspension and after that the difference is as just as you describe and can be negated.

Again, this is not directed to any company what so ever and for the vast majority of the companies out there this is not an issue. Just a few companies that use cheap material and cheap resign on the spiders. No, if you(anyone) PM me I can not and will not give you a list of said companies. Just because I know which because of various tests with a wide array of companies does not mean that I am allowed(by contract) to discuss what brands or particulars were used in said tests.

And to be fair, I have worked with and for a wide array of companies not just the last one which happened to be more "publicly known" because of the forum.

The idea of "break in" has been and will almost always discuss the driver finally coming into what the company would consider optimal playing conditions. It does not in most cases mean you can not beat on the sub right away. Many companies do use is as a ploy to void warranty though. I do hope the last part of that statements changes in the near future.

Id be glad to read any additional info you have (via PM). Because, and not to be argumentative here, the quality of the spider should not affect what Ive said above.

Again, if the spiders are more stiff when new, the suspension will simply allow less cone travel. 'Compliance' will only affect cone travel, it will not affect stress on the joints we are talking about (t-joint and spider landing). Spider is stiffer, thus cone moves less... versus spiders loosen up and cone moves further... the result will be virtually identical force applied to the joints holding these moving parts together. The amplifier output is not altered, so the same force is being applied to these parts (and the joints). Since you are applying the same force to the joints, the result will be the same amount of stress on those joints. Its simple physics.

Additionally, I dont see how a test could prove otherwise. You can only test a sub for pre-break-in characteristics once, so you either test it with no break-in (hook it up and wail on it) or you break it in and then wail on it. And testing two different subs will not prove anything, as even mass produced subs that are glued using machines will still have slightly different bonding properties due to variances in the amount of glue that contacts each part being bonded, differences in glue curing from one batch of glue and/or subs to another, etc. A definitive test would be extremely difficult. And if we are talking about a sub being manufactured by one of the small 'boutique' build houses that glue things by hand, we can throw any A/B comparison of two different subs right out the window altogether. So I find it difficult to even imagine a test that could prove conclusively what any specific sub would do if we did or did not break it in before flexing the suspension to its limits.

If you know of a manufacturer that has tested the break-in argument, I do not understand why they would not publish their results publicly, let alone expect/demand that you keep those tests and their results quiet here.

Id also like to add that if you were to push a sub hard before breaking it in, and it failed... chances are even if it hadn't failed immediately, it would have failed very soon, as clearly the user was pushing the sub to its ragged limits.

Again, no disrespect intended to you pro-rabbit, we simply disagree respectfully on this topic.

Really tough to disprove either since if you don't "break in" a woofer and it fails you can't then "break in" the same woofer and see if it fails since it's already broken.

Exactly.

 

[audioholic 5,000+ posts]

i may be wrong but i always heard its so th voice coil can wear in a grove and doesnt come unseated, but i may be wrong

This is a common mistake made by people who dont understand how a speaker works internally (no offense maljr1980). Many people think a speaker needs to be broke in like a car's engine, and use the 'wear a groove' argument because that's (somewhat) what happens in an engine. However, a speaker's voice coil does not rub against any surface like an engine's piston rings do, thus there is no 'groove' to wear in.

 

[pro-rabbit 5,000+ posts]

I agree completely with what you are saying and understand where you're coming from on this. Let me read through my notes on my contract to see what all that can be gone over.

The reason many tests like these are kept quite is because in most cases it disproves the idea that you need to "break in" a sub before use and that gives way to the window of warranty selection by the manufacturer. I do have several various tests from many companies, and the over all conclusion is that it is a myth. However, I do have a select few(very very few) companies that have the issue I described and after weeks of testing various ways the conclusion was that a break in time was needed to keep the issue from arising. There was not a glue failure though as that was tested as well. I will try and get back to you as soon as I can with some info via PM and maybe even a few pics if I can. It has been a bit since I last did one of the tests and perhaps I'm not remembering something that was very key to the studies....I am getting old so it is possible.. lol

 

[MONSONwarrior Premium Member]

I love these debates.