John L.
I cannot and will not be able to do any authoritative testing !
I am not opinionating when I state an observation that the EnABL pattern has not been tested within a driver/port situation where alternating pressures act upon edge/contour boundaries.
Also, John K's baffle surface results were first for a ring configuration that is not used (because it was known empirically to have no effect in such a fixed planar application?), then with the second test, the blocks were of insufficient size for baffle edge use, making the second baffle test no more relevant than the first.
If the tests do not match the application, then what are they supposed to show in relation to the application ?
Hi John K,
Ah, but I am listening !!!
And I am equally unimpressed by the
'after I tell you something, you just can't believe it'
approach being proffered here.
I cannot 'believe' without evidence that your baffle/transient test with observing mic back 9" over the driver provides a realistic audio examination, no matter what way you 'tell' me, because wave motion over a baffle is nothing like that which develops around say a driven loudspeaker dust-cap in the presence of coincidentally impinging wavefronts.
Alex has offered to provide you with an appropriate block dimension size/pattern for ports where energy exchange occurs between the alternating pressures developed within a port and the open air.
Any chance you could try this with the mic over the port (EnABLed) edge ?
Hi Bud,
Did you try the cone dot pattern 3/8" back from a planar baffle edge ?
I believe I read that any cabinet edge treatment with EnABL patterning had to be right at the edge itself, and be raised much higher than is applied to a cone, more like John's Mortite ring only with patterning.
Cheers ........... Graham.
I cannot and will not be able to do any authoritative testing !
I am not opinionating when I state an observation that the EnABL pattern has not been tested within a driver/port situation where alternating pressures act upon edge/contour boundaries.
Also, John K's baffle surface results were first for a ring configuration that is not used (because it was known empirically to have no effect in such a fixed planar application?), then with the second test, the blocks were of insufficient size for baffle edge use, making the second baffle test no more relevant than the first.
If the tests do not match the application, then what are they supposed to show in relation to the application ?
Hi John K,
Ah, but I am listening !!!
And I am equally unimpressed by the
'after I tell you something, you just can't believe it'
approach being proffered here.
I cannot 'believe' without evidence that your baffle/transient test with observing mic back 9" over the driver provides a realistic audio examination, no matter what way you 'tell' me, because wave motion over a baffle is nothing like that which develops around say a driven loudspeaker dust-cap in the presence of coincidentally impinging wavefronts.
Alex has offered to provide you with an appropriate block dimension size/pattern for ports where energy exchange occurs between the alternating pressures developed within a port and the open air.
Any chance you could try this with the mic over the port (EnABLed) edge ?
Hi Bud,
Did you try the cone dot pattern 3/8" back from a planar baffle edge ?
I believe I read that any cabinet edge treatment with EnABL patterning had to be right at the edge itself, and be raised much higher than is applied to a cone, more like John's Mortite ring only with patterning.
Cheers ........... Graham.
Graham Maynard said:
Graham,
The experimental applications of EnABL that have been done on ports and baffles have been done with a variety of methods, which even include aluminum foil and "band aids". The height of those is minimal, yet apparently yield very audible results.
JohnK's test should theoretically amplify the results of an EnABL pattern ring placed on the baffle around the driver, not minimize the effect. He even went one step further and placed a taller Mortite ring to show negligible wave disruption on the baffle as well.
This is all simply to try and isolate whether or not EnABL has any effect as a "boundary layer" modifier.
I think it really becomes far fetched when people start to ponder that .0035" tall pattern blocks could do anything at the low pressures and velocities of air we are talking about in ports and particularly baffle edges.
A proper test of BL EnABL effect would be done with a fluid running over EnABL blocks, or in a wind tunnel.
Despite knowing full well that it was than (much more than) highly unlikely, JohnK still went ahead and did his tests.
I think a lot of people here are just not getting how much education we are getting from JohnK's explanations, illustrations and test results.
No wonder he gets frustrated.....
Cheers
Daygloworange said:
Of even more significance, it's direct empirical evidence that the theoretical analysis done by John predicting no BL effects was undeniably correct. This is regardless of placement, whether on a moving surface such as a driver diaphragm or a non-moving surface such as a baffle or port. John's tests isolated the variables to one and one only, the impact of an application on the order of the enabl dimensions to an acoustic wave passing over it. That impact is essentially nil.
The import of that goes to the center of the debate on drivers. The proof that there is no BL nor even dimensionally related impact (as in diffraction by the application) on an acoustic wave passing over the application leaves only one logical conclusion as to the effect on a driver. That is, the alteration in frequency response is nothing more than classical mechanics, i.e., added mass, damping and localized stiffening of the diaphragm. To conclude otherwise is to deny that facts.
Dave
DLR got it completely wrong .......
Hi,
Having perused the much shorter subjective thread other than the
useful advice regarding the application of the process it is as dull
as dishwater.
Subjectively BudP deems it fit to fill it full of the "night and day" /
"chalk and cheese" subjective descriptions he is so fond of, and
without any objective critisism they appear to me to come across
as more damning than informative to an enquiring mind.
JMO, read the thread, no debate has its consequences on credibility.
(The nature of the thread is simply that the subjective naysayers
with any sense will simply not bother with it, resistance is futile ...)
No debate (in a forum !?) is also boring ..... very boring.
Seems the mistake DLR (hope you don't mind this assumption) made
was that all the non-objective gobbledygook / pseudotechnowaffle /
unrational self opininiation, which is objectively for the most part is
essentially meaningless, would remain in the other thread.
Not a chance ..... who defines what is objective ?
/sreten.
Hi,
Having perused the much shorter subjective thread other than the
useful advice regarding the application of the process it is as dull
as dishwater.
Subjectively BudP deems it fit to fill it full of the "night and day" /
"chalk and cheese" subjective descriptions he is so fond of, and
without any objective critisism they appear to me to come across
as more damning than informative to an enquiring mind.
JMO, read the thread, no debate has its consequences on credibility.
(The nature of the thread is simply that the subjective naysayers
with any sense will simply not bother with it, resistance is futile ...)
No debate (in a forum !?) is also boring ..... very boring.
Seems the mistake DLR (hope you don't mind this assumption) made
was that all the non-objective gobbledygook / pseudotechnowaffle /
unrational self opininiation, which is objectively for the most part is
essentially meaningless, would remain in the other thread.
Not a chance ..... who defines what is objective ?
/sreten.
Hi Daygloworange,
You say port testing has already been done; but was this using a transient, or with regular wavemotion generated pressures/velocities?
If John K's test were repeated on a port and the results were not significant there either, compared to what is heard, then would this not show that the impulse/time test is not the correct tool to be investigating EnABL with ?
On the other hand, if it did show change within a tuned port, then cannot similar not be expected to arise within the volume of a driven cone?
Please do not think I fail to understand the significance of John K's tests, for what has not been revealed by them is every bit as important.
Cheers ........ Graham.
You say port testing has already been done; but was this using a transient, or with regular wavemotion generated pressures/velocities?
If John K's test were repeated on a port and the results were not significant there either, compared to what is heard, then would this not show that the impulse/time test is not the correct tool to be investigating EnABL with ?
On the other hand, if it did show change within a tuned port, then cannot similar not be expected to arise within the volume of a driven cone?
Please do not think I fail to understand the significance of John K's tests, for what has not been revealed by them is every bit as important.
Cheers ........ Graham.
Notice how quiet I've been after JohnK's last data? I realy don't have any tests to prove the contrary yet.Daygloworange said:
I think, if anyone is going to question results from a test, is to either do tests that show differently, or ask for more data from the test in question.
So I agree that JohnK has provided sufficient data to prove his point for this particular type of driver and baffle.
Re: DLR got it completely wrong .......
I've got to agree with you on the first part. It's ironic given the glee of some when they were told that there would be a separation. The answer to the second one is easy. By a definition that should logically apply, objective in this context means:
It should be overwhelmingly obvious as to which comments are objective and which ones are not.
Dave
sreten said:Hi,
Seems the mistake DLR (hope you don't mind this assumption) made
was that all the non-objective gobbledygook / pseudotechnowaffle /
unrational self opininiation, which is objectively for the most part is
essentially meaningless, would remain in the other thread.
Not a chance ..... who defines what is objective ?
I've got to agree with you on the first part. It's ironic given the glee of some when they were told that there would be a separation. The answer to the second one is easy. By a definition that should logically apply, objective in this context means:
It should be overwhelmingly obvious as to which comments are objective and which ones are not.
Dave
One of the things I was going to address is the momentum exchange between a vibrating surface and the air (or other fluid) in contact with it. I wrote something up but I just think it's too complex to really add much to the discussion. Plus, if you are really interested you can go to the library and look it up in any good book on fluid dynamics that has a decent section on acoustics.
But in simple words, what is required it to write a momentum a balance at the surface. Right out of F = ma. What find is that you start with the basic equation of fluid dynamics which states that the acceleration of the fluid is equal to the sum of the pressure forces and a group of shear forces resulting from viscous action. When an analysis is made to see which of these terms contribute to the momentum exchange it is found that the fluid acceleration is equal to the pressure gradient in the direction of the surface velocity. If the surface velocity is in the direction normal (perpendicular) to the surface, then this states that the normal pressure gradient is equal to the time rate of change of the surface velocity. When the viscous forces are examined it is found that they aren't a factor at audible frequencies, and in fact don't become significant until gigahertz frequencies are reached. Once the radiation leaves the cone the wave development remains a linear relationship between presssure (and gradients) and velocity (and gradients) which leads to the linear wave equation. Furthermore, even if you look at cases where the pressures are so high at the surface than nonlinear acoustics must be considered, there is nothing that enters the picture that would result in enable patches altering the momentum transfer from cone to air. The nonlinear effects would be just as prevalent in treated and untreated cones, etc.
As far as enable patches disrupting wave behavior all that is really needed is to look at what is fairly well understood in acoustics, and further demonstrated by my simple experiments isolating the patches from a vibrating surface. Before something becomes acoustically visible it needs to be of the order of 1/10 a wave length or greater in size. At 20k Hz that comes in at about 0.067". If you consider an enable patch 0.0035" high, it would be expected to see something altered in the 380,000 Hz range. With a 1/8" obstruction an effect would be expected at around 10800 Hz. This is obviously consistent with the data I took.
So from everything I have looked at I can summarize as this: Enable patterns as would be applied to a driver cone can not affect the propagation of audible acoustic waves on any surface, cone, dust cap, phase plug.... Enable patterns as applied to cones can not alter the mechanism of transfer of momentum from the cone to the air. This leaves us back where we started, all that enable can do is alter the distribution of momentum over the cone surface, or as previously stated, Enable can only alter the distribution of cone surface velocity with observed effects in frequency response, etc. There just isn’t much more to say other than for the sake or arguing. Actually I wish there were some other interesting thread around because at this point the horse is so dead it’s starting to smell. I almost wish something would show up out of left field to point this in another direction.
The other thing, as I expect many of the readers here have, I check in on the other split of this thread and frankly all I see is a lot of “how to do it” with next to no “this is what it did.” Actually I was hoping to see a lot more people coming out of the woodwork reporting their successes or failures.
But in simple words, what is required it to write a momentum a balance at the surface. Right out of F = ma. What find is that you start with the basic equation of fluid dynamics which states that the acceleration of the fluid is equal to the sum of the pressure forces and a group of shear forces resulting from viscous action. When an analysis is made to see which of these terms contribute to the momentum exchange it is found that the fluid acceleration is equal to the pressure gradient in the direction of the surface velocity. If the surface velocity is in the direction normal (perpendicular) to the surface, then this states that the normal pressure gradient is equal to the time rate of change of the surface velocity. When the viscous forces are examined it is found that they aren't a factor at audible frequencies, and in fact don't become significant until gigahertz frequencies are reached. Once the radiation leaves the cone the wave development remains a linear relationship between presssure (and gradients) and velocity (and gradients) which leads to the linear wave equation. Furthermore, even if you look at cases where the pressures are so high at the surface than nonlinear acoustics must be considered, there is nothing that enters the picture that would result in enable patches altering the momentum transfer from cone to air. The nonlinear effects would be just as prevalent in treated and untreated cones, etc.
As far as enable patches disrupting wave behavior all that is really needed is to look at what is fairly well understood in acoustics, and further demonstrated by my simple experiments isolating the patches from a vibrating surface. Before something becomes acoustically visible it needs to be of the order of 1/10 a wave length or greater in size. At 20k Hz that comes in at about 0.067". If you consider an enable patch 0.0035" high, it would be expected to see something altered in the 380,000 Hz range. With a 1/8" obstruction an effect would be expected at around 10800 Hz. This is obviously consistent with the data I took.
So from everything I have looked at I can summarize as this: Enable patterns as would be applied to a driver cone can not affect the propagation of audible acoustic waves on any surface, cone, dust cap, phase plug.... Enable patterns as applied to cones can not alter the mechanism of transfer of momentum from the cone to the air. This leaves us back where we started, all that enable can do is alter the distribution of momentum over the cone surface, or as previously stated, Enable can only alter the distribution of cone surface velocity with observed effects in frequency response, etc. There just isn’t much more to say other than for the sake or arguing. Actually I wish there were some other interesting thread around because at this point the horse is so dead it’s starting to smell. I almost wish something would show up out of left field to point this in another direction.
The other thing, as I expect many of the readers here have, I check in on the other split of this thread and frankly all I see is a lot of “how to do it” with next to no “this is what it did.” Actually I was hoping to see a lot more people coming out of the woodwork reporting their successes or failures.
Hi John K,
My challenge to test response with EnABL in a port stands because you have been observing for (disturbed/reflected) wavefront amplitude changes in time, not the modification of wavemotion at and due to localised surface pressure change related effects.
Any chance ?
Cheers ......... Graham.
My challenge to test response with EnABL in a port stands because you have been observing for (disturbed/reflected) wavefront amplitude changes in time, not the modification of wavemotion at and due to localised surface pressure change related effects.
Any chance ?
Cheers ......... Graham.
Graham Maynard said:
Actually I would think it would show that the people who claim to have heard changes in the sound of port on a speaker are probably hearing what they what they want to hear, and not any sort of real change.
Remember the measurement tools being used here are the same ones that are used by Seas, Scan Speak etc. when they design the drivers in the first place. If tools such as MLS measurements are adequate to design the drivers in the first place, they are adequate to measure the phenomena being being talked about here.
To me this is a lot like insisting that Jessica Simpson is smart, and when a standard IQ test taken thousands of times by other people shows that she really isn't that bright, blaming the test.
Regards,
Dennis
Graham Maynard said:
Graham,
Haven't done the tests yet. Day job keeps getting in the way, but it will be tested shortly.
With the help of Alex from Oz's Excel spreadsheet, I will generate computer generated and cut adhesive backed vinyl into EnABL patterns for application on ports and baffle edges, and they will be tested and measured.
If there was a measured change in a port application, then yes, I would agree, other tests would have to be derived to isolate the changes measured.
But let's see first if there are any changes to be measured at the port.
I will go one step further. A good friend of mine, who's business is located a few doors down from mine, is a specialist in acoustics and vibration control.
http://www.jsal.freeservers.com/Main.htm
I'll present him with the details and claims of the EnABL patent and get his expert opinion.
I also have a friend who is a leading edge expert on fluid dynamics and airfoil shapes, who works on turbines and wind powered generators. I'll pick his brain about it as well.
Cheers
Daygloworange said:
G'day Daygloworange,
Where is the transparency?
BEFORE ANY TESTING IS DONE it is important to confirm to ALL contributors in this thread that you are testing EXACTLY the application of EnABL that I have described.
I am the only one making the outrageous claims with regard to ports and baffles.
Therefore, it seems more than reasonable that you post details of the proposed test application so that I can publicly confirm its relevance and validity in relation to my own experiments.
All contributors should also be given the chance to comment on the testing conditions and proposed set of measurements.
It appears that you are serious in giving due diligence to the testing of EnABL and providing some proper objective (truly unbiased) measurement data.
So, lets conduct this investigation openly and with input and consultation from all interested parties.
There is no point generating yet another abstract set of measurement data.
Does this sound reasonable?
Cheers,
Alex
Alex,
No need to jump the gun. I haven't gone ahead with anything yet.
Other than look at your spreadsheet, and confirm with RAW Acoustics that they would agree to test EnABL on baffles and ports, I haven't done anything. As I've mentioned, I've been too busy with work.
You can bet your bottom dollar that I won't go through all the effort of getting the patterns made, sent off for application and testing, only to have the results poo poo'd.
Since you are the one who has the most experience with these applications of EnABL, we will do it in such a way to best replicate your results.
No worries. I will consult with you first, before any work is done.
Cheers
No need to jump the gun. I haven't gone ahead with anything yet.
Other than look at your spreadsheet, and confirm with RAW Acoustics that they would agree to test EnABL on baffles and ports, I haven't done anything. As I've mentioned, I've been too busy with work.
You can bet your bottom dollar that I won't go through all the effort of getting the patterns made, sent off for application and testing, only to have the results poo poo'd.
Since you are the one who has the most experience with these applications of EnABL, we will do it in such a way to best replicate your results.
No worries. I will consult with you first, before any work is done.
Cheers
Alex from Oz said:
uh..no... I don't believe anyone is required to pass some sort of "pre-screening" of their techniques and methods. Let's wait and see how the tests progress. If they choose to divulge the test setup, that's their business...
You seem to be insinuating that John K's results are an abstraction... doesn't seem that way to me...
those who wish to comment on the validity of results presented will do just that, I'm sure. And, no you're not the only one claiming significant improvement results from dots on baffles and such by a long shot.
John L.
Graham Maynard said:
The port is a very different problem than edge diffraction or damping standing wave on a cone. It's more of a classic fluid dynamics problem and there can be a classical, oscillatory fluid boundary layer on the port walls. However, there are also much bigger disruptions to the fluid dynamics caused by the entrance and exit effects. A small enable patch isn't going to do much to either the wave propagation in the port or to any boundary layer on a port wall compared to the typical port termination problem.
On the other hand, if the obstruction is of such a size as to seriously restricts flow through the port then the resistive nature of the port will need to be considered and there could potentially be a change in the characteristic acoustic impedance of the port, due to changes in the effective port area, which could result in different wave reflections, etc, in the port. But I wouldn't call this an enable effect since it would really be just standard acoustic phenomena. It seems to me that the idea of enable treatment is that a small, seemingly insignificant change results in a big difference in sound. Should we next call filling the port with straws a form of enable? Where do we draw the line between what is referred to as enable and what is more of less standard acoustic treatments, tried and true, that have been applied over the years. I’m not incline to consider placing ¼” or ½” blocks of felt around a baffle edge an enable treatment, no matter what the pattern of the block is.
If you want me to paint dashes on a port wall, or use my pin striping tape and measure the output I'll be happy to do it. There won't be any different, if I add 1/8" high Mortite rings there may be a difference, if I fill the port with straws I'm pretty sure there will be a difference.
Alex from Oz said:
I think it is fine if you want to test your approach, but my interest is with what Bud has defined as Enable. And I am really only interested in what enable can do when applied to a driver. My tests were never really aimed at diffraction or ports. That was an aside due to the responses posted here. The crux on my tests were, and remain, isolating an enable pattern, as would be applied to a driver, from cone vibration and studying the passage of acoustic wave over them.
What is appropriate here is, what ever is tested, is to report it as such. If you want to test scalloped edges and call it enable, fine. Just make sure you tell us about the edge treatment. If you want to stick a sock in a port and call it enable, fine. Just let us know whether the sock was cotton or wool.
JohnK,
His name is Paul (can't remember his last name right at the moment). He and another friend of mine were collaborating on the wind turbine stuff.
I will contact him and show him the EnABL patent, and see if he would like to comment.
I'll pass along his contact info to you when I do get to talk to him. This guy is pretty well versed in airfoil shapes. He drives around with this rig on top of his car for testing, a la Burt Rutan, mind boggling stuff...
Can anyone point me to where I could find the patent info on EnABL, so I can pass it on to these guys?
Cheers
His name is Paul (can't remember his last name right at the moment). He and another friend of mine were collaborating on the wind turbine stuff.
I will contact him and show him the EnABL patent, and see if he would like to comment.
I'll pass along his contact info to you when I do get to talk to him. This guy is pretty well versed in airfoil shapes. He drives around with this rig on top of his car for testing, a la Burt Rutan, mind boggling stuff...
Can anyone point me to where I could find the patent info on EnABL, so I can pass it on to these guys?
Cheers
auplater said:
John L, I am perplexed by your comments?!
The proponents of EnABL been
- open in describing exactly how the process is applied
- placed under intense, relentless scientific scrutiny
- been ridiculed for providing no objective data
Most of this thread is filled with
- test results which some claim as proof that EnABL does not work
- requests for clarification of the posted test results
- questions regarding the suitability of the tests performed
- sarcasm from the 'objectivists' when the rest of us don't just roll over and accept the results.
Let's suppose I acquired some test gear and posted measurements as PROOF that EnABL worked.
Without full and complete details of the test conditions would you, or john k or dlr and anyone else roll over accept and that without scrutiny?
ABSOLUTELY NOT!
Those who are willing to comprehensively test EnABL must be put under scutiny in relation to technical details around exactly what is tested and how.
There is no sensible reason not to have discussion and disclosure prior to testing.
Anyone who really wants to ensure the objectivity of this technical thread should be delighted to take this approach.
Cheers,
Alex
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