Genelec The Ones woofer creases/tearing mystery solved

[DonH56]

Force is a vector, with amplitude and direction. If you've ever taken a bike or car around a corner it is a familiar concept. I am not a speaker designer, though have done some, but basic linear mechanics (remembering my one course in mechanical engineering from way back when) will show you why "wrinkles" in the surrounds are needed/helpful since the stress on the surround during excursion (movement) is not equal when you change direction like that (from straight to semicircular at the ends). A circle applies stress evenly at all points (ideally) but when you have an oblong or rectangular driver then stress on the surround comes at different directions where it changes orientation. The "wrinkles" allow the sections at the end to flex more without having the surround non-linearly modulate cone movement and add more distortion.

FWIWFM -Don

 

[73hadd]

I think people are entitled to ask as many questions as they want before spending their money. Sometimes answering annoying questions is part of how manufacturers earn their money. Yes they've spent the thousands of hours on engineering, but educating the market (as Genelec has done here) is a good thing. Manufacturers are, IMHO, less entitled to our money, than we are entitled to their information.

If this were a speaker with a visible woofer I think the OP would have been satisfied by being able to go to store and look at a few, or get a few pictures from other users. Wasn't it less about deliberate ignorance or mistrust, and more about lack of sample set data? (which again, Genelec has solved.)

Worthwhile discussion IMHO. Thank you for the contribution.

 

[Pearljam5000]

Are paper drivers more sensitive to the weather / humidity and have related problems like mold?

 

[thewas]

Are paper drivers more sensitive to the weather / humidity and have related problems like mold?

If the paper is not coated mold can be more difficult to remove/clean than from a smooth surface like a metal or polymere membrane.

 

[617]

Are paper drivers more sensitive to the weather / humidity and have related problems like mold?

'paper' in this context is a complex blend of organic and inorganic fibers and fillers held together with a variety of binders and sizing chemicals. It's hard to generalize which of these composites would perform well in humid environments, but there are paper transducers designed for outdoor applications. PHL makes some very nice ones.

Also as someone else pointed out, these cones are not made with flat sheets of paper, but are paper pulp which is molded into the proper shape.

Paper chemicals - Wikipedia

en.wikipedia.org

Sizing - Wikipedia

en.wikipedia.org

Just to get an idea of how varied 'paper' as a category of material is.

 

[Pearljam5000]

'paper' in this context is a complex blend of organic and inorganic fibers and fillers held together with a variety of binders and sizing chemicals. It's hard to generalize which of these composites would perform well in humid environments, but there are paper transducers designed for outdoor applications. PHL makes some very nice ones.

Also as someone else pointed out, these cones are not made with flat sheets of paper, but are paper pulp which is molded into the proper shape.

Paper chemicals - Wikipedia

en.wikipedia.org

Sizing - Wikipedia

en.wikipedia.org

Just to get an idea of how varied 'paper' as a category of material is.

My brain is used of thinking of paper as :

 

[auraluxstudio]

Now that I have seen these photos, they don't look so bad and look even more smooth close up. Some better than others. Puts my mind to rest a little.

 

[Pearljam5000]

Now that I have seen these photos, they don't look so bad and look even more smooth close up. Some better than others. Puts my mind to rest a little.

The question is would you buy them or avoid bases on that Pic alone?

 

[Scoox]

Now that I have seen these photos, they don't look so bad and look even more smooth close up. Some better than others. Puts my mind to rest a little.

I guess the take-home message is Genelec have been open about it (though it did take some work) and, if this turns out to be a problem down the line, they would have to retrofit all 8351B with an improved driver to preserve customer goodwill and reputation, even if the monitors are out of warranty. It would be very difficult for such a trusted company to get away with trying to brush a critical flaw under the rug. We are talking about a monitor that costs a substantial amount of money and that's being used in many professional studios.

I've owned quite a few monitors over the years and I agree this looks unusual, and given the option I'm sure all of us would prefer a perfectly smooth finish, but Genelec have already shown us images to prove all drivers are like this to slightly varying degrees so it's clearly something they are aware of and I doubt they would have released a flagship product knowing it had a critical flaw, therefore it must be non-critical, and if it is critical users will notice and Genelec will sort it out for us.

The 8361A drivers look a bit more uniform, looking at those pics if you don't mind spending a bit more money you'd get better LF extension and peace of mind.

 

[tktran303]

The problem is that you’re using your eyes judge something.

In acoustics asymmetry or irregularity is important. We need to use our ears and what’s between our ears to judge something.

A perfectly square room, a perfectly round cabinet, a perfectly symmetrical concert hall. A perfectly smooth and shiny surface.

It’s NOT good. It’s just creating opportunities for reflections which means resonances.

Companies need to employ marketers to write things like “deeply impregnated with high tech fibres” and because lay people seem to think smooth and shiny is better.

If that were true we’d line our living rooms with as many mirrors or smooth shiny surfaces as we can. Or easier- bring our speakers into your bathroom and play them.

Speaker cones are the same- it ain’t designed for looks like your car’s finish, it’s designed for sound.

 

[Scoox]

lay people seem to think smooth and shiny is better.

I don't think that's the standard people were using to judge the product here. I myself am a fan of a matte finish because it generally doesn't attract fingerprints and is tougher. However, a matte finish is a similar to white noise, where the randomness happens evenly across the spectrum and nothing stands out. In the original pictures one could observe certain "features" within the rough area of the driver which were referred to as "tears" and "wrinkles". It's the fact that these features stand out and yet don't exhibit any specific predictable geometrical pattern (i.e. they look random) that can and did cause some people to worry, myself included, because randomness and variance usually mean that the manufacturer lacks full control over the manufacturing process, which is not a good thing. Therefore it's not unreasonable that some users seek to investigate how these unplanned features affect the sound coming out of their expensive monitors, and whether the difference in sound will be audibly significant from monitor to monitor.

The other way to look at this is that Genelec engineers design every part of their products using CAD software. The 3D model inside the software didn't feature the wrinkles and was probably smooth like the other areas of the cone. The "wrinkles" were observed afterwards as a result of the manufacturing process and the materials used. The randomness of the wrinkles confirms they are neither intentional nor fully predictable (if they were intentional they would look symmetrical top and bottom, left and right and be identical from monitor to monitor), but Genelec confirms they are not cause for concern.

My theory is that, in order to get rid of these wrinkles, adhesives or other substances would need to be added to the cone material which would make it heavier thereby interfering with its ability to reproduce low frequencies precisely. It's a bit like baking a cake: you adjust the proportions of the ingredients until you get the desired results. Some recipes cause the cake to crack at the top but maybe that's the recipe that tastes best, then you need to decide if you want your cake to look good or to taste good. Likewise, the composite material used for the LF cones is the result of extensive R&D by Genelec engineers leading to the optimal "recipe" that produces the best possible sound whilst remaining mechanically adequate—the wrinkles are the small aesthetic price that has to be paid for arguably one of the best sounding monitors on the market today.

 

[tktran303]

There’s well known driver manufacturers who ended up having to put a pigment into their drivers; from the natural off-white colour with visible yellow fibres interspersed in it) to all black; because customers complained that it looked “dirty”

And other drivers that had a proprietary fibre mix ended up having a cost reduced version for OEM, resulting in a satin gloss finish.

So now you know. No more need to theorise or worry.

 

[Pearljam5000]

The question is, if there are wrinkles to begin with, won't they in time get bigger or deeper or something and then the sound will change or the driver will stop working all together ?

 

[Scoox]

The question is, if there are wrinkles to begin with, won't they in time get bigger or deeper or something and then the sound will change or the driver will stop working all together ?

I assume they don't get bigger over time, since Genelec stress-test their drivers and they have already said it's within the manufacturing tolerances. That said, I have a feeling Genelec will sort out the wrinkles in future drivers just to avoid drama, if possible at all.

 

[mightycicadalord]

I don't see genelec changing anything about their speakers due to some crazy forum user. This was never even an issue from the get go and anyone with a brain would have been more than satisfied with genelecs responses. The only drama I saw was from users who lacked the critical thinking skills to properly interpret the info they were given.

 

[Scoox]

I don't see genelec changing anything about their speakers due to some crazy forum user. This was never even an issue from the get go and anyone with a brain would have been more than satisfied with genelecs responses. The only drama I saw was from users who lacked the critical thinking skills to properly interpret the info they were given.

Actually, engineering companies are constantly looking for stuff to do to keep employees on the payroll. There is always room for refinement and I'm sure we'll see new revisions of this monitor.

 

[caught gesture]

The question is, if there are wrinkles to begin with, won't they in time get bigger or deeper or something and then the sound will change or the driver will stop working all together ?

What about if there are not wrinkles to begin with and in time stress causes distortion or tearing of the driver or something and then the sound will change or the driver will stop working altogether?

 

[-Matt-]

Why all the talk about paper?

The wrinkles are clearly in the rubber compliance surround, NOT in the paper cone itself.

EDIT: I have now looked at the other thread and see that you were actually talking about cracking at the edge of the cone. I think a simple annotation of the photo could have saved a lot of confusion. (Like this):

Red region is cracking at edge of the cone. Blue regions are wrinkles on the rubber surround.

EDIT 2: After looking through the original tread I can see that this topic has already been thoroughly covered. I regret adding to it.

 

[thewas]

@Ilkka Rissanen from Genelec commented about those creases:

Genelec 8351B Teardown (2nd Disassembled)

My good buddy 'Devil's Advocate' asked me to ask a simpleton question, and not directed to anyone specifically: What really is the love affair (infatuation?) with powered/active speakers, anyways? If I must; I can understand 'plug-in' boards, in sum rear access panel. I fully understand (and...

www.audiosciencereview.com

Genelec 8351B Teardown (2nd Disassembled)

My good buddy 'Devil's Advocate' asked me to ask a simpleton question, and not directed to anyone specifically: What really is the love affair (infatuation?) with powered/active speakers, anyways? If I must; I can understand 'plug-in' boards, in sum rear access panel. I fully understand (and...

www.audiosciencereview.com

 

[YSC]

I assume they don't get bigger over time, since Genelec stress-test their drivers and they have already said it's within the manufacturing tolerances. That said, I have a feeling Genelec will sort out the wrinkles in future drivers just to avoid drama, if possible at all.

well if it completely tears off in say, 10 years and came up with some replacements which is improved I will actually be happy, as Genelec type company tend to do free service to refurb old speakers out of warranty with that sort of problem, so I will get a free upgrade