dlr,
Just copying a phrase used in other posts that refer in a derogatory fashion to the Positive Feedback on line magazine in that fashion, a group who were happy to publish the "white paper" originally presented to them by Clark Johnson, one of their contributors. The paper ends with some limited, CSD derived images, of a cone tweeter that I and Larry Arnst, who performed the tests in 1987, thought showed standing wave ringing being curtailed on the EnABL'd driver. The paper can be found here.
http://www.positive-feedback.com/Issue21/standingwaves.htm
My wife has corrected my memory. She said that I also did an edit of the paper when I received the final patent drawings, to be used for the patent, and included them. So another edit in 1994 to add the placement drawings for patterns, on various surfaces.
Bud
Just copying a phrase used in other posts that refer in a derogatory fashion to the Positive Feedback on line magazine in that fashion, a group who were happy to publish the "white paper" originally presented to them by Clark Johnson, one of their contributors. The paper ends with some limited, CSD derived images, of a cone tweeter that I and Larry Arnst, who performed the tests in 1987, thought showed standing wave ringing being curtailed on the EnABL'd driver. The paper can be found here.
http://www.positive-feedback.com/Issue21/standingwaves.htm
My wife has corrected my memory. She said that I also did an edit of the paper when I received the final patent drawings, to be used for the patent, and included them. So another edit in 1994 to add the placement drawings for patterns, on various surfaces.
Bud
"My wife has corrected my memory. She said that I also did an edit of the paper when I received the final patent drawings, to be used for the patent, and included them. So another edit in 1994 to add the placement drawings for patterns, on various surfaces. Bud"
--- and if she is like my wife she most likely remembers what you were wearing and where you were at -- 😀
--- and if she is like my wife she most likely remembers what you were wearing and where you were at -- 😀
BudP said:
Wait, do you mean Clark Johnsen, the guy that writes articles like this about CD "tweaks"?
That somehow "grinding" the edges with a $500 stage prop resulted in OMG audible (improvements of course) effects?
If that doesn't border on insanity....
BTW, why did you choose to demonstrate it on a 50 cents boombox tweeter IIRC, rather than say, a VIFA or Seas midrange cone of that era?
cheers,
AJ
Graham Maynard said:
The nature of EnABL is modification of a driver through added mass and damping in a distributed manner. But the real issue is the output of the driver as a system. As a system, the transfer function (no matter what mechanism is conjectured) is a fully measurable characteristic.
"Music induced alternations" simply have far less in the way of spectrum content than does any impulse used in measurement. You continue to try to make it appear as if music signals impose more complex signals on a driver. They do not.
Dave
AJ,
Actually it was from a Bic three way system, not that it wasn't cheap. And, I had no idea what a Vifa or Seas was, or where to obtain them.
I was poor, that is what I could afford at the time and the test was free, so Mr Arnst decided what to test. Since I knew nothing about CSD, less about what a Franklin computer might be and was sorta familiar with what a microphone was, I didn't argue. I was sent along to him by Cal Perkins, a well known pro sound engineer in the NW. I met him because we were building transformers for Sun Music and he needed some samples designed and built for a Fender amp he was developing, for Fender.
Cal had heard a different set of speakers, because I wanted an opinion from someone who at least knew the rules. After pointing out that the tweeter was out of phase, and correcting that, he said the sound was good enough that I should have the drivers tested. So, I purchased the cheap Bic speakers and contacted Larry Arnst. The speakers Cal heard belonged to someone else.
Bud
Actually it was from a Bic three way system, not that it wasn't cheap. And, I had no idea what a Vifa or Seas was, or where to obtain them.
I was poor, that is what I could afford at the time and the test was free, so Mr Arnst decided what to test. Since I knew nothing about CSD, less about what a Franklin computer might be and was sorta familiar with what a microphone was, I didn't argue. I was sent along to him by Cal Perkins, a well known pro sound engineer in the NW. I met him because we were building transformers for Sun Music and he needed some samples designed and built for a Fender amp he was developing, for Fender.
Cal had heard a different set of speakers, because I wanted an opinion from someone who at least knew the rules. After pointing out that the tweeter was out of phase, and correcting that, he said the sound was good enough that I should have the drivers tested. So, I purchased the cheap Bic speakers and contacted Larry Arnst. The speakers Cal heard belonged to someone else.
Bud
Hi Dave,
Thanks for your reply. You wrote
>> You continue to try to make it appear as if music signals impose more complex signals on a driver. <<
The signal to the driver does not change, but airmolecule movements nearest to the cone could modify transduction arising in series with voice coil and mechanical impedances.
Music waveforms are already complex, and our parallel processing hearing capabilities are very capable of detecting harmonics at one frequency being out of phase (group delay shifted in time) with those at others, and especially if music energisation is alternating those shifts wrt the fundamental, and thus we might hear EnABL reducing that music induced variation.
Sines won't show this.
I am also thinking more about the full-range aspects here, not multi-driver systems where the harmonic relationships have become severed anyway, not that FRs are free of phase changes either.
Cheers ........... Graham.
Thanks for your reply. You wrote
>> You continue to try to make it appear as if music signals impose more complex signals on a driver. <<
The signal to the driver does not change, but airmolecule movements nearest to the cone could modify transduction arising in series with voice coil and mechanical impedances.
Music waveforms are already complex, and our parallel processing hearing capabilities are very capable of detecting harmonics at one frequency being out of phase (group delay shifted in time) with those at others, and especially if music energisation is alternating those shifts wrt the fundamental, and thus we might hear EnABL reducing that music induced variation.
Sines won't show this.
I am also thinking more about the full-range aspects here, not multi-driver systems where the harmonic relationships have become severed anyway, not that FRs are free of phase changes either.
Cheers ........... Graham.
If this is scraping the CD edge so that it slants in an angle, and then marking the slanted edge with black market. This does make some improvements, but much smaller compared with driver tweaks. I have two of the same CDs and did try it. HDCDs seems to show more significant improvement with this treatement.AJinFLA said:
Graham Maynard said:
That implies directly that drivers are not linear devices. Within their operating ranges they are with the exception of motor non-linearities that EnABL can have absolutely no impact upon other than the impact (amplification of the non-linear output) by the resonances that are altered. There is no shifting of harmonic relationships within the normal range. If harmonics are out-of-phase through group delay, they'll be measured as out-of-phase, it's that simple. They'll also stay that way. What you claim doesn't square with the known physics of piston drivers, full-range or not, like it or not. Group delay is a basic characteristic of a driver, again easily measured.
If a driver has serious problems between the low signal and high signal response, EnABL is not going to correct it.
There may certainly be changes in a driver's output, but using conjecture (and that's all that anyone has actually used in support) to ascribe something counter to the physics is no support for what actually does change with a modification, essentially the resonances inherent in the particular driver. Full-range drivers usually have the most serious issues with resonances (as easily seen in any measurement of them), so I'm not surprised that the biggest impact is reported on them.
Dave
This is way off-topic
I've never gone in for any of this type of tweak, though anti-jitter devices did show audibility on older players. The idea, I think, behind the CD edge tweak is that the treated edge absorbs any "scattered" laser light. The CD pits are read by their transitions, IIRC. That is where the CD production facility influence is found. The timing of the reading of the pits can be altered due to pit spacing and/or pit edge sensing that can introduce jitter. Early CD was highly susceptible to this timing issue due to the total lack of understanding of the concept of jitter. That's well known now.
The idea behind the edge treatment is that the "scattered" laser light can be reflected back by the edge and interfere with the timing of the pit sensing. This, too me, is very dubious, as it implies that the timing of the laser light sensor's detection of the pit transitions can be affected by highly randomized reflections.
In addition, any and all jitter can be controlled or at least minimized at the DAC. I have used various CD and DVD players with outboard DACs. The transport simply has no effect on newer players unless it is failing to read pits and using interpolation as part of its correction, which they do. I'm very familiar with the latter case as the original CD-as-transport I used for years started to fail. The failure was made dramatically apparent with HDCD because I had the setting in the D/A so that HDCD played as recommended with a 6db difference between standard and HDCD. If there was any alteration in the digital data whatsoever, the HDCD algorithm totally failed and the audio level would jump up and down that 6db. This is why you can't use any dither with HDCD, it causes total failure of the HDCD algorithm since it's embedded in the digital signal and is destroyed by any kind of change, dither or error correction interpolation.
If you are hearing a change with a CD edge treatment in an HDCD disc and there is no level change, either the HDCD algorithm is totally corrupted throughout the entire playback time (implying constant error correction interpolation) or the difference must be in the jitter component. If it's the latter, the D/A is incapable of correcting for the jitter of the transport. Good D/A systems re-clock the incoming digital stream and should at this time be able to eliminate any transport induced jitter. The MSB Link DAC I now use upsamples. The transport has no effect that I can detect, though my older Audio Alchemy D/A benefited by the use of the AA anti-jitter device, though this was much more noticeable when the I2S connection was used. The MSB upsampling and re-clocking eliminates all upstream jitter issues.
Dave
soongsc said:
I've never gone in for any of this type of tweak, though anti-jitter devices did show audibility on older players. The idea, I think, behind the CD edge tweak is that the treated edge absorbs any "scattered" laser light. The CD pits are read by their transitions, IIRC. That is where the CD production facility influence is found. The timing of the reading of the pits can be altered due to pit spacing and/or pit edge sensing that can introduce jitter. Early CD was highly susceptible to this timing issue due to the total lack of understanding of the concept of jitter. That's well known now.
The idea behind the edge treatment is that the "scattered" laser light can be reflected back by the edge and interfere with the timing of the pit sensing. This, too me, is very dubious, as it implies that the timing of the laser light sensor's detection of the pit transitions can be affected by highly randomized reflections.
In addition, any and all jitter can be controlled or at least minimized at the DAC. I have used various CD and DVD players with outboard DACs. The transport simply has no effect on newer players unless it is failing to read pits and using interpolation as part of its correction, which they do. I'm very familiar with the latter case as the original CD-as-transport I used for years started to fail. The failure was made dramatically apparent with HDCD because I had the setting in the D/A so that HDCD played as recommended with a 6db difference between standard and HDCD. If there was any alteration in the digital data whatsoever, the HDCD algorithm totally failed and the audio level would jump up and down that 6db. This is why you can't use any dither with HDCD, it causes total failure of the HDCD algorithm since it's embedded in the digital signal and is destroyed by any kind of change, dither or error correction interpolation.
If you are hearing a change with a CD edge treatment in an HDCD disc and there is no level change, either the HDCD algorithm is totally corrupted throughout the entire playback time (implying constant error correction interpolation) or the difference must be in the jitter component. If it's the latter, the D/A is incapable of correcting for the jitter of the transport. Good D/A systems re-clock the incoming digital stream and should at this time be able to eliminate any transport induced jitter. The MSB Link DAC I now use upsamples. The transport has no effect that I can detect, though my older Audio Alchemy D/A benefited by the use of the AA anti-jitter device, though this was much more noticeable when the I2S connection was used. The MSB upsampling and re-clocking eliminates all upstream jitter issues.
Dave
FrankWW said:
Thanks for the information, I downloaded the paper (courtesy of my university). The main part is about the analytical derivation of solutions from the wave equation for a circular and annular membrane with an added damping in the description for the membrane tension. For several boundary conditions (loading schemes) results are shown. It is rather advanced mathematics, so I need to study it more carefully before I can comment on it.
dlr Dave...
Quote "The idea, I think, behind the CD edge tweak is"
Quote "The transport simply has no effect on newer players unless it is failing to read pits and using interpolation as part of its correction"
Quote "The transport has no effect that I can detect"
Dave: it sounds to me that you require a scientific statement or premise as to how things work or operate. Should this rational meet with your understanding and seem credible then that is an ok working system for you. Should the premise or theory not hold up to your scientific scrutiny then it fails to pas your reality check and you can't see that it can work at least not the way it was described to. I guess that this works for most things that are developed inside your system or paradigm but it does not apply for things out side of it.
I can hear the effect of disk edge sanding. I can hear the effect of washing and waxing disks. I can hear the effect of cryo treatment of a disk. I can hear the impact of switching to a better transport. I can hear the effect of changing a power cord or a digital cable on a transport. Hearing these things makes me ask questions such as why and how these changes could have such impact on what I hear. It is because I hear these things that the questions arise. If I did not hear any changes there would be no questions. It is the knowledge gathered from my senses that leads me to question. If science or my understanding of it does not answer or explain my questions that does not change what I know my senses have told me. My sensory input is what drives me to find an explanation so that a better working understanding can be developed. It would seem that you just don't believe all of what I hear and I dont believe all of what science says. So some kind of middle ground needs to be found so we can work together. I see science as a tool that may help reach an explanation rather than an explanation. Am I guessing correctly that you see subjective observations in the same way that I view science?
Quote "The idea, I think, behind the CD edge tweak is"
Quote "The transport simply has no effect on newer players unless it is failing to read pits and using interpolation as part of its correction"
Quote "The transport has no effect that I can detect"
Dave: it sounds to me that you require a scientific statement or premise as to how things work or operate. Should this rational meet with your understanding and seem credible then that is an ok working system for you. Should the premise or theory not hold up to your scientific scrutiny then it fails to pas your reality check and you can't see that it can work at least not the way it was described to. I guess that this works for most things that are developed inside your system or paradigm but it does not apply for things out side of it.
I can hear the effect of disk edge sanding. I can hear the effect of washing and waxing disks. I can hear the effect of cryo treatment of a disk. I can hear the impact of switching to a better transport. I can hear the effect of changing a power cord or a digital cable on a transport. Hearing these things makes me ask questions such as why and how these changes could have such impact on what I hear. It is because I hear these things that the questions arise. If I did not hear any changes there would be no questions. It is the knowledge gathered from my senses that leads me to question. If science or my understanding of it does not answer or explain my questions that does not change what I know my senses have told me. My sensory input is what drives me to find an explanation so that a better working understanding can be developed. It would seem that you just don't believe all of what I hear and I dont believe all of what science says. So some kind of middle ground needs to be found so we can work together. I see science as a tool that may help reach an explanation rather than an explanation. Am I guessing correctly that you see subjective observations in the same way that I view science?
H Dave,
I feel that you cannot imagine what I am attempting to write about.
I had some nasty comments back at me when I broached similar activity within SS amplifiers related to NFB causing *audible* group delay effects which cannot be measured conventionally due to output and source being fractionally separated in time due to frequency dependent series reactance which is energiced by reactive LS loading. (Much like voice coil and cone, with frequency dependent reactive loading of the cone.)
The outcome for me was a SS amplifier which does not suffer from music induced group delay variation due to LS reactivities.
You keep refering everything back to known cone vibration and vibration modes, which is not what I am alluding to.
Cheers .......... Graham.
I feel that you cannot imagine what I am attempting to write about.
I had some nasty comments back at me when I broached similar activity within SS amplifiers related to NFB causing *audible* group delay effects which cannot be measured conventionally due to output and source being fractionally separated in time due to frequency dependent series reactance which is energiced by reactive LS loading. (Much like voice coil and cone, with frequency dependent reactive loading of the cone.)
The outcome for me was a SS amplifier which does not suffer from music induced group delay variation due to LS reactivities.
You keep refering everything back to known cone vibration and vibration modes, which is not what I am alluding to.
Cheers .......... Graham.
Graham Maynard said:
What you are writing with regard to individual driver response is conjecture, nothing more. You have no basis in any empirical sense. Empirical data directly refutes much of it. Science is not inadequate as is implied in much of this thread.
Amps are a different thing altogether and will only serve to confuse the issue. There's no need to mention other posters "nasty comments", it's of no concern when discussing the merits here. I also don't get into amp discussions. They have no bearing on properly made driver measurements. The issues with them are easily eliminated with regard to measurement. Accurate and effective MLS measurements use a feedback signal taken from the driver input terminals that effectively eliminates all upstream issues to obtain the transfer function of the driver exclusive of other influences, pre-amps, amps, everything. I've made measurements with cheap amps, high quality amps, widely varying wiring, interconnects, whatever. I can get nearly perfect repeatability. The issue is nothing more than the driver output as a system. Input signal vs. acoustic output, correlated with the feedback from the input signal.
What you describe concerning speakers is still conjecture based on perceptions attempting to explain those perceptions. Whatever you are hearing is measurable in some form or another and in now way invalidates effective empirical investigations.
Perception involves in-room system response and is a whole new arena for discussion and should really not be part of this thread as far as describing the mechanism. Perceptions by listening in-room add a whole new set of uncertainties that cannot be fully separated. This of course is on top of the well-known short term memory for audio. Believe me I am acutely aware of this as I did a lot of experimenting years back before I ever got into any DIY. I listened only. I switched in/out all kinds of things I was testing or auditioning. I know the influences of the placebo effect and how hard it is to eliminate them or correctly contrast when there's any time at all between tests/auditions. It's my ears that got me into this in the first place.
In the end the output of a driver before, then after modification of any sort is a simple matter and easily measured as far as a system concern. It's not a complicated issue, despite efforts to make it appear so. I trust my ears to tell me there's a difference. There's nothing to trust in ears determining the mechanism of some modification of a driver and I've modified my share.
Dave
Re: dlr Dave...
No, you don't know me. But I'm also not going to get into an argument about what you think you hear. Let's not go there. If you're happy sanding CD edges, keep doing so. All of this shouldn't be in this thread anyway. This will be my last post on any off-topic discussion.
Dave
moray james said:
No, you don't know me. But I'm also not going to get into an argument about what you think you hear. Let's not go there. If you're happy sanding CD edges, keep doing so. All of this shouldn't be in this thread anyway. This will be my last post on any off-topic discussion.
Dave
Not yet (have to lend a digicam first, mine went away with ex-girlfriendBudP said:
). But I can show a picture of the whole speaker, because it is found on ebay all the time. It was sold for about $40/pair at a local food store, and that should tell how it sounds like. Those drivers are 6.5" (and not true molded polyprop but rather look like coated paper, I have to correct that -- forgot to mention that earlier). Not all four driver are equal, the lower ones work into BR loading and have sligthly greater magnets, all else looking equal (I haven't measured them as of now). I didn't use nail polish (turned out to be too soft) but used hard/elastic "nu-enamel" paint from Amstrong, Chicago, which is based on synthetic resin. Was that a wrong choice?- Klaus
Attachments
dlr said:
But is that a valid assumption, that drivers are pistons? I do know that that assumption was made early on, but largely to make the math easier, not because the scientists/engineers believed it strictly true.
Bud, can you point out that eranek reference again?
dave
planet10 said:
That was meant more for the type of driver, as opposed to compression, planar, ribbon, etc., though they are similar insofar as measurements are concerned, though each may have some unique requirements when measuring. Drivers aren't perfect pistons, of course. This is where distortion measurements become useful, especially as power increases.
However, one requirement when evaluating any mod is the measurement conditions have to remain constant. That is, the same or nearly the same power needs to be used for the before/after tests. If this is not followed, then any test results will be flawed, especially if the driver has a less than stellar motor, since distortion, both linear and non-linear, generally increases with driver displacement.
Dave
You will have less luck with PP or coated stiffened papaer.KSTR said:Not yet (have to lend a digicam first, mine went away with ex-girlfriend
- Klaus
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