Vibration damping

Dans le message de
news:[email hidden],
Ted Bennett <[email hidden]> a réfléchi, et puis a déclaré :

Quoted message said:

Sandy said:

Quoted message said:

All that Specialized has provided is smoke and mirrors. My
instincts tell me that when smoke and mirrors are being employed,
there's something being hidden...and it's usually fungible with a
big sign that says "scam".

With all the disbelief expressed this thread, and previously, I am
truly surprised no one is brave enough to give the FTC a nice little
call to put an end to this "scam". Unless, of course, the naysayers
really don't have the right story. Either the stuff works, and
Specialized is entitled to market it as they see fit, or they are
defrauding the public, and should be severely disciplined.

So, who is the taker out there to make the bold step forward and put
his/her reputation on the line, expertise on the table, and undress
this falsehood.

Don't you brave souls all run to the phone, now ...

The FTC has nothing to say about this issue.

Specialized's claims were carefully crafted by crafty wordsmiths, and
they make no fraudulent claims or deceptions as the FTC defines them.
If they say that their Zertz damp some vibration at the top of the
seat tube, compared to the source in the BB, I believe them. Of
course, that may not have any effect on the vibrational spectrum that
the rider meets. The rider always wears pants (with some notable
exceptions http://www.barewitness.org/worldnakedbikeride04.html ) and
often gloves, usually seated on a flexible saddle.

Certainly, Specialized manages to convey the impression that their
bikes are more comfortable than others. That is safe because comfort
is a highly subjective matter. It is fraudulent in a different
sense, a lie of the second kind. If it was possible to prohibit this
and yet retain free speech (and it is not) virually all advertising
firms would vanish in a puff of smoke and a crashing of breaking
mirrors.

Doesn't this sort of thing happen in France, Sandy? I don't think you
have to think long or hard to come up with an example of misleading
puffery in L'Express.

Stop with this outdated "puffery" be it in the US or in France. If it's
false, and you seem to write that it is NOT false, then they are correct.
If it is perceived by a rider, then it is even less false - more factual.
But if it is false, as many claim here, yes, the FTC can correct the
situation, were they to have an interest. Those who appear to have such an
interest also seem to have an interest in propping up their own erudition
without the courage of confronting Specialized directly. Again, who is
brave enough to take that step ? I don't "buy" every statement from
marketing. Nor do you. But it takes more than harumphing to settle this.
--
Sandy
Verneuil-sur-Seine
*******

La vie, c'est comme une bicyclette,
il faut avancer pour ne pas perdre l'équilibre.
-- Einstein, A.

dvt said:

Sorry, no test data on their claims. Heck, I haven't even ridden a
Zertz-equipped bike, although I have been very happy with the two
Specialized bikes I have owned and I've been very happy with their
customer service. But the claims they make and the way they present the
data instill scepticism.

I test rode an S-Works Tarmac, and a Roubaix. The former I rode from
Mike's Bikes in the South of Market neighborhood in San Francisco:
the street conditions there being more characteristic of a war zone
than a modern city. I was really surprised at how little I felt the potholes,
it was a striking comparison to my Al Team Fuji with a carbon fork.

Now, I don't claim the Zertz does anything. But the accumulation of factors
in the design clearly is doing something. It wasn't just the tire
pressure.

Dan

Ted Bennett said:

Mark Hickey said:

dvt said:

Sandy wrote:
> With all the disbelief expressed this thread, and previously, I am truly
> surprised no one is brave enough to give the FTC a nice little call to put
> an end to this "scam".

The data is not a lie, as far as I can tell.

Precisely. I could legally and truthfully claim my frames "damp 50%
more vibration than Brand X". The fact that this makes no difference
wouldn't enter into the equation - other than on a moral basis, which
is what keeps me from doing so (better to sleep well than to sell the
occasional extra frame due to hype).

Mark "zzzzzzzzzzzzz" Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

Oh, man am I happy to see this. I might even consider purchasing one of
your frames now. If only other sellers would adopt this attitude, we
could free up a lot of marketers for productive work.

Hey, if they could DO productive work, they wouldn't be marketers!

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

David L. Johnson said:

Ted Bennett said:

Oh, man am I happy to see this. I might even consider purchasing one of
your frames now. If only other sellers would adopt this attitude, we
could free up a lot of marketers for productive work.

I have one of Mark's frames, and am very happy with it -- except that it
keeps wanting to veer right on me....

Just doing my bit to make the world a better place.... ;-)

Quoted message said:

So, Mark, is that why you don't sell track frames, that they have to turn
left all the time?

Hey, I can't help it if everyone races the wrong way! Besides, if
they veered left, it'd put you into traffic.

Mark "Hmmmm... what's this do to my UK customers?" Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

Quoted message said:

David L. Johnson said:

Quoted message said:

With all the disbelief expressed this thread, and previously, I am
truly surprised no one is brave enough to give the FTC a nice
little call to put an end to this "scam". Unless, of course, the
naysayers really don't have the right story. Either the stuff
works, and Specialized is entitled to market it as they see fit, or
they are defrauding the public, and should be severely disciplined.

Quoted message said:

Or, maybe it doesn't make a dime's worth of difference, but the
company can get either buyer testimonials or "test data" to justify
their claims. Companies can get such data and testimonials for all
sorts of products, from cancer cures to miracle carburetors.

I was given a set of Bontrager handlebar dampers that look like
elongated bar end plugs made of soft rubber with "swirl" spokes
between inner and outer mass. The demo was that a bare set of
handlebars dropped on the concrete floor clanged loudly and with the
plugs in, only the high frequencies remained.

What was overlooked is that my bars with a full wrap of Cinelli bar
tape don't clang at all, high or low frequency. I'm amazed how these
marketing guys come up with this stuff. These bar plugs are claimed
to insulate the rider from road texture generated buzz as in:

http://tinyurl.com/7xxok

This is probably the same spiel they give for the damping of carbon
fiber frames.

So, what is your point: that damping handlebar vibration is possible by the
addition of constrained elastic materials? Well yeah, that's what Bontager
claims also. That using a mass suspended in the elastic material to tune the
frequencies to be damped is not possible?

You have not tested the product and found it ineffective and you haven't
expressed anything meaningful to disprove the claims made.

If you simply think that this is not a necessary investment, then sure, you're
entitled to your opinion. It will be noted along with the very wide range of
cycling related inventions that you consider needless.

Now, I've got no dog in this, I don't use the 'zerts or whatever gadawful name
that was, or the handlebar gadgets. But I am amazed at how the criticism of
these products is as full of jargon, rhetoric, handwaving and plain old [censored]
as the advertising copy itself. Probably moreso, since the manufacturer is
presenting an honest to God product backed by their own money and exposed to
CPSC recalls, lawsuits, insurance claims and all the other slings and arrows of
modern business.

Ron

Dan said:

I think you are onto something good here Jobst. If anybody is tempted to
fork out big bucks for a frame with gimmicky dampers they should wrap the
chainstays and seatpost of their old bike with bar tape and see if they can
detect a difference.

In other words, you agree that the principle claimed by the manufacturer is
valid, but you prefer to apply damping to the outside of the tube for whatever
reason.

Quoted message said:

The bar wrap will probably damp more vibrations than
Zertz.

No, it probably won't. It will do every bit as well at preventing a ringing
sound, but probably nothing effective in lower frequency vibration felt in the
frame.

Ron

"RonSonic" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Dan said:

I think you are onto something good here Jobst. If anybody is tempted to
fork out big bucks for a frame with gimmicky dampers they should wrap the
chainstays and seatpost of their old bike with bar tape and see if they
can
detect a difference.

In other words, you agree that the principle claimed by the manufacturer
is
valid, but you prefer to apply damping to the outside of the tube for
whatever
reason.

The principle of damping is certainly valid but the manufacturer has not
demonstrated that Zertz achieve any damping of any frequency. I just think
it would be good for persons tempted to buy a Zerty bike to try a cheaper
and probably better damping sytem first although I doubt that an objective
rider would detect any difference. I suppose that I do agree that damping
out vibrations can make a bike more comfortable but Zertz and bar tape won't
do it. Shocks and fat tires would.

Quoted message said:

Quoted message said:

The bar wrap will probably damp more vibrations than
Zertz.

No, it probably won't. It will do every bit as well at preventing a
ringing
sound, but probably nothing effective in lower frequency vibration felt in
the
frame.

So you agree that bar tape will damp out vibrations. Preventing a ringing
sound is damping out a high frequency range and bar tape may very well do a
better job of this than Zertz but such high frequencies have nothing to do
with riding comfort unless the ringing is making your head ache. I doubt
that Zertz or bar tape will damp out anything that is related to cycling
comfort.

Quoted message said:

Ron

Sandy said:

But if it is false, as many claim here,

Can you provide a citation of that?

--
Dave
dvt at psu dot edu

Dans le message de news:[email hidden],
dvt <[email hidden]> a réfléchi, et puis a déclaré :

Quoted message said:

Sandy said:

But if it is false, as many claim here,

Can you provide a citation of that?

Not a citation, but a clear recall of the comments from F Krygowski [sp?]
and M Hickey.
They took me to task a while back, and I'm sure that the archives (the
searching of which would involve work, and it's Friday, and it's dark, and
research isn't too interesting) would guide you. If I have mischaracterized
their comments, they have only to tell me that, here, and I will go look up
(tediously) those past conversations. Or you could, if you like.
--
Bonne route !

Sandy
Verneuil-sur-Seine FR

Sandy said:

Dans le message de news:[email hidden],
dvt <[email hidden]> a réfléchi, et puis a déclaré :

Quoted message said:

Sandy wrote:

Quoted message said:

Quoted message said:

Quoted message said:

But if it is false, as many claim here,

Quoted message said:

Quoted message said:

Can you provide a citation of that?

Quoted message said:

Not a citation, but a clear recall of the comments from F Krygowski [sp?]
and M Hickey.
They took me to task a while back, and I'm sure that the archives (the
searching of which would involve work, and it's Friday, and it's dark, and
research isn't too interesting) would guide you. If I have mischaracterized
their comments, they have only to tell me that, here, and I will go look up
(tediously) those past conversations. Or you could, if you like.

I'm not interested enough to dig it out.

--
Dave
dvt at psu dot edu

"Dan Connelly" <d_j_c_o_n_n_e_l@i_e_e_e.o_r_g> wrote in message
news:[email hidden]...

Quoted message said:

dvt said:

Sorry, no test data on their claims. Heck, I haven't even

ridden a

Quoted message said:

Quoted message said:

Zertz-equipped bike, although I have been very happy with the

two

Quoted message said:

Quoted message said:

Specialized bikes I have owned and I've been very happy with

their

Quoted message said:

Quoted message said:

customer service. But the claims they make and the way they

present the

Quoted message said:

Quoted message said:

data instill scepticism.

I test rode an S-Works Tarmac, and a Roubaix. The former I

rode from

Quoted message said:

Mike's Bikes in the South of Market neighborhood in San

Francisco:

Quoted message said:

the street conditions there being more characteristic of a war

zone

Quoted message said:

than a modern city. I was really surprised at how little I

felt the potholes,

Quoted message said:

it was a striking comparison to my Al Team Fuji with a carbon

fork.

Quoted message said:

Now, I don't claim the Zertz does anything. But the

accumulation of factors

Quoted message said:

in the design clearly is doing something. It wasn't just the

tire

Quoted message said:

pressure.

How did it compare with your Fuji in other respects, like when
climbing or sprinting? I would think that any frame with
significant shock absorption would also need a lock-out to be
solid in a sprint. -- Jay Beattie.

Jay Beattie said:

How did it compare with your Fuji in other respects, like when
climbing or sprinting? I would think that any frame with
significant shock absorption would also need a lock-out to be
solid in a sprint. -- Jay Beattie.

Sprinting was fine. The bottom bracket quite stiff. I didn't climb with it,
but I saw nothing to indicate it would be a problem.

Dan

Dan said:

The principle of damping is certainly valid but the manufacturer has not
demonstrated that Zertz achieve any damping of any frequency. I just think
it would be good for persons tempted to buy a Zerty bike to try a cheaper
and probably better damping sytem first although I doubt that an objective
rider would detect any difference. I suppose that I do agree that damping
out vibrations can make a bike more comfortable but Zertz and bar tape won't
do it. Shocks and fat tires would.

True enough. One of the favorite bikes I've ever ridden:
http://www.djconnel.com/photos/VietnamThailand2005/hue_djcbike.jpg

Another similar one I rode up behind:
http://www.djconnel.com/photos/VietnamThailand2005/hue_loadedcyclist.jpg

I rented the bike in Hue, Vietnam, mid-November for 10000 dong / day (approx $0.65).
No security deposit, BTW, or any verification of personal info. (Scam attempts
are extremely common, while theft, apparently, is not).

Anyway, I'm sort of amused by what are considered low-end transportation
bikes in the US -- even ultra-cheap full-suspension rigs. This was much
better.

Anyway, obviously the issue on the Specialized bike is to have comfort
on rough roads combined with crisp handling, light weight, and low rolling
resistance. It is, after all, a racing bike. So fat tires and low pressure
isn't necessarily the way to go.

Dan

Sandy said:

... a clear recall of the comments from F Krygowski [sp?]
and M Hickey.
They took me to task a while back, and I'm sure that the archives (the
searching of which would involve work, and it's Friday, and it's dark, and
research isn't too interesting) would guide you. If I have mischaracterized
their comments, they have only to tell me that, here, and I will go look up
(tediously) those past conversations.

I don't think anyone said the graphs Specialized posted were false.
What we said were things like: Why would anyone be interested in
damping vibrations in the frequencies of musical notes? (440 Hz is a
standard "A" musical note, after all.) One does not normally perceive
sound with their ass.

The frequencies that might bother your ass will not be in the musical
range. Furthermore, Specialized plotted the difference in ... what?
(The label on the vertical axis is unreadable)... between the axle and
the saddle, or between the axle and the handlebars.

And golly gee, whatever they're using to measure vibration is reduced!
Holy cow! How convincing!

But wait - shouldn't they be comparing the results of frames _with_ vs.
_without_ their magic inserts? Hmmm - the graphs don't actually do
that. Is it probable that _any_ frame would do _some_ vibration
damping? Actually, yes. IOW, their graphs are designed to be
truthful, yet misleading.

Those who have no training in interpreting such things can obviously be
very impressed by scientific looking garbage. ("Fast Fourier
Tranforms! Wow!!!"😉 It takes a little background to recognize the
techno-blather.

Furthermore, as discussed previously, there's been no explanation for
how a 440 Hz vibration is going to make it from the road through the
many-times-softer tire, and the many-times-softer saddle. IOW, they've
got a gimmick they _claim_ will remove vibration frequencies that are
probably not there to any detectable extent, because they're absorbed
by other components.

To the aggressively gullible, these points are incomprehensible. They
say "It's advertized, and the government that takes care of us all has
not complained, so it MUST be true!!!"

But we've been around and around on those points. There's not much
point in trying to educate the gullible.

- Frank Krygowski

I went shopping for a new bike a few weeks ago, after my commuter bike
was stolen. I decided that a cyclocross bike was the perfect thing and
narrowed my choices down to Specialized Tricross Comp and an aluminum
Redline Conquest. The Specialized bike hads Zertz fork, seatpost, and
handlebar. The Specialized bike gave a much more comfortable ride and
felt like more my old steel touring bike, but lighter. The Redline was
rock-solid, which would probably be good for a twenty-year-old athlete,
but no so good for a forty-eight-year-old enthusiast.

So far I've been on one ride of 50 miles and several shorter rides of
about 30 miles in addition to my regular short commute and have found
the bike very comfortable and easy to live with. I think that the Zertz
inserts help my comfort level on the bike.

Sandy said:

... it seems that we simply don't know the
answer, right ? That the /opinions/ offered against the Specialized claims
are no more substantial than the claims themselves. And, that they are not
untrue, false, misleading, etc. OK.

It is not essential that you stick your hands into the flames to
verify that the fire in front of you is as hot as the ones that you
have had experience with in the past. Tuned vibration damping systems
have been around for a long time, they are well understood, and they
can be quite effective...but they're effectiveness is *known* to be
limited to a narrow frequency range (and, for that matter, plane of
motion in most cases), so the claims made by Specialized can be judjed
meritless merely on the basis of their being at variance with the
known capabilities of the technology. Like the thousands of patent
applications presented over the years for perpetul motion machines,
the mere fact that they are making claims in excess of the limitations
of the tech is adequate grounds to dismiss their wodnergadget as a
marketing ploy if not an outright fraud; it may very well work for a
very small range of frequencies, but the range that requires damping
is very large, and the frequencies at which such a technique would be
likely to be effective are highly unlikely to be within the range of
those damped. In point of fact, if you look at the graphs they
present, it appears that the greatest damping is in the area of 400Hz,
and that the damping is negligible or absent in the area of the
greatest vibration they recorded (down around 50Hz), where the
amplitude of the noise was an entire order of magnitude greater.
Thus, even their own numbers say it's not doing much...if anything.
There is nothing whatsoever presented which shows that the same loss
of frequency transmission would not have taken place in a Zertz-less
frame, and without that, their claims have no basis.

The burden is on them to show that the device is effective; it is not
on us to demonstrate that it isn't.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

Frank Krygowski said:

Quoted message said:

... a clear recall of the comments from F Krygowski and M Hickey.

Quoted message said:

Quoted message said:

They took me to task a while back, and I'm sure that the archives
(the searching of which would involve work, and it's Friday, and
it's dark, and research isn't too interesting) would guide you. If
I have mischaracterized their comments, they have only to tell me
that, here, and I will go look up (tediously) those past
conversations.

Quoted message said:

I don't think anyone said the graphs Specialized posted were false.
What we said were things like: Why would anyone be interested in
damping vibrations in the frequencies of musical notes? (440 Hz is a
standard "A" musical note, after all.) One does not normally
perceive sound with their ass.

Quoted message said:

The frequencies that might bother your ass will not be in the
musical range. Furthermore, Specialized plotted the difference in
... what? (The label on the vertical axis is unreadable)... between
the axle and the saddle, or between the axle and the handlebars.

Quoted message said:

And golly gee, whatever they're using to measure vibration is
reduced! Holy cow! How convincing!

Quoted message said:

But wait - shouldn't they be comparing the results of frames _with_
vs. _without_ their magic inserts? Hmmm - the graphs don't
actually do that. Is it probable that _any_ frame would do _some_
vibration damping? Actually, yes. IOW, their graphs are designed
to be truthful, yet misleading.

Quoted message said:

Those who have no training in interpreting such things can obviously
be very impressed by scientific looking garbage. ("Fast Fourier
Transforms! Wow!!!"😉 It takes a little background to recognize the
techno-blather.

Quoted message said:

Furthermore, as discussed previously, there's been no explanation
for how a 440 Hz vibration is going to make it from the road through
the many-times-softer tire, and the many-times-softer saddle. IOW,
they've got a gimmick they _claim_ will remove vibration frequencies
that are probably not there to any detectable extent, because
they're absorbed by other components.

Quoted message said:

To the aggressively gullible, these points are incomprehensible.
They say "It's advertized, and the government that takes care of us
all has not complained, so it MUST be true!!!"

Quoted message said:

But we've been around and around on those points. There's not much
point in trying to educate the gullible.

But Ron Sonic says:

Quoted message said:

Quoted message said:

So, what is your point: that damping handlebar vibration is
possible by the addition of constrained elastic materials? Well
yeah, that's what Bontrager claims also. That using a mass suspended
in the elastic material to tune the frequencies to be damped is not
possible?

Quoted message said:

Quoted message said:

You have not tested the product and found it ineffective and you
haven't expressed anything meaningful to disprove the claims made.

Quoted message said:

Quoted message said:

If you simply think that this is not a necessary investment, then
sure, you're entitled to your opinion. It will be noted along with
the very wide range of cycling related inventions that you consider
needless.

How about showing that this stuff does any palpable good rather than
others having to prove that there is no magic in day-glo orange
rubber. As I said, the convincing demo I got was that a bare aluminum
handlebar clanged without the damper, and with the mere 17g of
material stuffed into each end of the bar, damped out the mid range
clang. Meanwhile my bars with bar tape damp out all acoustic
resonances. If there is more to it then the advertising demo is ill
chosen to show the effect.

Besides, I have no complaint in those frequency ranges. It's rough
roads with embedded rock that bounce me around.

Jobst Brandt

Quoted message said:

How about showing that this stuff does any palpable good rather than
others having to prove that there is no magic in day-glo orange
rubber. As I said, the convincing demo I got was that a bare aluminum
handlebar clanged without the damper, and with the mere 17g of
material stuffed into each end of the bar, damped out the mid range
clang. Meanwhile my bars with bar tape damp out all acoustic
resonances. If there is more to it then the advertising demo is ill
chosen to show the effect.

Besides, I have no complaint in those frequency ranges. It's rough
roads with embedded rock that bounce me around.

The resonant frequency of a spring-mass system is sqrt(k/M) (units:
sqrt(force/distance/mass) = sqrt(acceleration/distance) = sqrt(1/time^2)).
The k value for a bicycle tire is related to the
derivative of vertical deflection wrt supported
load, where the supported load is approx Mg/2, and the deflection is somewhere in
the range of 5 mm. Clearly deflection (d) is sublinearly proportional to load, as
contact patch is increasing with load. A crude estimate is afforded by just
taking the ratio, which I will multiply by 2 due to the increase in contact
patch wrt deflection. So k ~ Mg/2 / d * 2 = Mg / d. Sqrt(k/M) is then
sqrt( g/d ). Assume I pump my tires up to yield a fixed d. For d = 5mm,
I get 44 sec^-1, or 7 Hz.

So this tells that frequencies up to approximately 7 Hz are transmitted
through the tires efficiently, so frequencies more than a few times this
are strongly attenuated.

Dan

Dans le message de
news:[email hidden],
[email hidden] <[email hidden]> a réfléchi, et puis a déclaré :

Quoted message said:

Furthermore, as discussed previously, there's been no explanation for
how a 440 Hz vibration is going to make it from the road through the
many-times-softer tire, and the many-times-softer saddle. IOW,
they've got a gimmick they _claim_ will remove vibration frequencies
that are probably not there to any detectable extent, because they're
absorbed by other components.

Your argument leads, without exaggeration, to a rule whereby any material
capable of holding together under the forces of typical riding use - be that
solid pasta, bamboo, or the more typical frame materials - will not exhibit
significant differences in the transmission of vibrations, because the
saddle and the wheels and the pneumatics will make those differences
imperceptible. Or are you saying something like the curve is too close for
*you* to tell ?

Quoted message said:

To the aggressively gullible, these points are incomprehensible. They
say "It's advertized, and the government that takes care of us all has
not complained, so it MUST be true!!!"

Quoted message said:

But we've been around and around on those points. There's not much
point in trying to educate the gullible.

The point to doing that would be to get rid of the claim, so future gullible
consumers are not distracted from wondering if it's really true that red
bikes are faster.

With your qualifications, I imagine it would take a five minute phone call
to the FTC to convince them that Specalized is misinforming the public with
deceptive and untrue claims. So, I guess you are going to make that bold
move.
--
Bonne route !

Sandy
Verneuil-sur-Seine FR

Dans le message de news:[email hidden],
Werehatrack <[email hidden]> a réfléchi, et puis a déclaré :

Quoted message said:

Sandy said:

... it seems that we simply don't know the
answer, right ? That the /opinions/ offered against the Specialized
claims are no more substantial than the claims themselves. And,
that they are not untrue, false, misleading, etc. OK.

It is not essential that you stick your hands into the flames to
verify that the fire in front of you is as hot as the ones that you
have had experience with in the past.

.... meaning you figure all frame materials and constructions offer the same,
invariable capacity to damp vibrations ?

Quoted message said:

Tuned vibration damping systems
have been around for a long time, they are well understood, and they
can be quite effective...but they're effectiveness is *known* to be
limited to a narrow frequency range

Sorry I have no credentials as an engineer, but I thought that frequency
attenuation or magnification requires systems of /various/ sorts pertinent
to the characteristics of which frequencies you wish to treat. Things like
violins and tennis racquets may strike a chord [that was fun !].

Quoted message said:

(and, for that matter, plane of
motion in most cases), so the claims made by Specialized can be judjed
meritless merely on the basis of their being at variance with the
known capabilities of the technology.

Do you mean meritless as in "false" ?

Quoted message said:

Like the thousands of patent
applications presented over the years for perpetul motion machines,
the mere fact that they are making claims in excess of the limitations
of the tech is adequate grounds to dismiss their wodnergadget as a
marketing ploy if not an outright fraud;

That's the harumphing I was referring to ...

Quoted message said:

it may very well work for a
very small range of frequencies, but the range that requires damping
is very large,

Both Mr Brandt and Mr Krygowski are at odds with you, here. And they don't
seem, AFICT, to agree between themselves. I would definitely like to
understand if they are in accord.

Quoted message said:

and the frequencies at which such a technique would be
likely to be effective are highly unlikely to be within the range of
those damped. In point of fact, if you look at the graphs they
present, it appears that the greatest damping is in the area of 400Hz,
and that the damping is negligible or absent in the area of the
greatest vibration they recorded (down around 50Hz), where the
amplitude of the noise was an entire order of magnitude greater.

Good point, yes.

Quoted message said:

Thus, even their own numbers say it's not doing much...if anything.
There is nothing whatsoever presented which shows that the same loss
of frequency transmission would not have taken place in a Zertz-less
frame, and without that, their claims have no basis.

It's not fair to say that there is no basis. The basis of the claim is that
within the skeleton, their claims are substantiated by their data. Another
manufacturer may show that their tests show even greater attenuation under
the same input. Or, they may themselves show, in a future "improved Zertz"
version, that they surpass what was obtained in this one.

Quoted message said:

The burden is on them to show that the device is effective; it is not
on us to demonstrate that it isn't.

Not really, if they _have_ shown it, within their limited universe of
demonstration.

I really don't have an investment in this, but I don't think that scoffing
is the way to prove your point.
--
Bonne route !

Sandy
Verneuil-sur-Seine FR
--
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