Walsh termination
_______________________
Moderator Note:
The beginnings of this thread -- the 1st 68 posts have been copied out of 3 other threads.
Beyond the Ariel
OHM Acoustics "Walsh F" Speaker remakes
Help me kill a fostex artifact.
If some of the comments don't make sense it will be because they are out of their original context

_______________________
Hi All,
This is the beginning of a rather curious post. I have been bouncing around a few threads saying speculative sounding things about a speaker driver and associated baffle surfaces treatment, that does not look feasible, on first approach.
A moderator has agreed to create this thread, that has all of the pogo-ing posts in one place so everyone can doubt at once.
What I am portraying in these posts is a concept for controlling edged and smooth taper terminus zones. These zones are responsible for the bulk of what is wrong with modern drivers. They cause reflected standing waves, circulating Raleigh waves and diffractive emissions at the final terminus of a "speaker system". Almost all of these reflected artifacts are transient in nature. This means they do dissipate and without an extended dissipation period, due to particular materials used.
That their dissipation over time has a profoundly corrupting influence upon following sound energy and it's resultant reflections is quite obvious, when you get them to stop. What is not obvious is how pervasive the corruptions are. Speakers should theoretically provide infinite detail, complete with "musician applied color" and instrument induced transients and their resultant decays, all of them. Speakers should reproduce the sound field recorded, with enough spatial cues and time to arrival cues, to allow our millions of years old, audible threat assessment system, with it's semi autonomous correlator, to finish recreating the sonic event being reproduced with a fluency and ease that does not tire us nor force us try to hear beyond some irritating noise that interferes.
This EnABL process, portrayed in the following post series, does remove these transient artifacts, produced by uncontrolled reflections and refractions. This is not a theory. It works. It is also so good at this removal that it will not seem possible, for someone who has not tried it themselves, to believe. The qualitative statements you will find, as the braver and more adventurous DIY'rs try it out, will simply not be creditable. "Nothing could be that good" will be the thought and nothing could be farther from the truth, either. There are levels of treatment, having to do with how much your skill at hearing corruptions has developed, and, how maniacal your activities are. But just the most rudimentary attempt will bring huge benefit to your reproduced sound. The real learning process, after a few treated speakers, will be in determining how much is enough.
I will be providing a guided tour through treating a pair of Lowther drivers. I know next to nothing about these speakers and their idiosyncratic sound, but I am certain to horrify those who are devoted to these devices. I apologize to you for this insult, but the person who owns the Lowther’s has asked politely and pretty forcefully that I proceed.
I will not be making any before and after Quantitative measurements. I am going to leave that to you folks who really do know what you are doing in that realm. Of course that means you will have to treat a set of drivers, or two, but I will not be upset about this. I will suggest that very little, of what is a profound qualitative improvement, is going to show up in the usual tests. At least that has been my experience, but, I am not qualified to do these tests anyway. You who must, should probably start qualifying the results of this process with a CSD plot.
There are two documents on line you can refer to.
The first is posted at Positive Feedback Online, Issue 21 at this url http://www.positive-feedback.com/Issue21/standingwaves.htm This will give you some ground to understand from and does provide a truncated CSD on a cone, "phenolic ring" tweeter at the end of the paper. Take special notice of the last pair of comparisons, this is what all of these words are in honor of.
The other is a patent document found at where ever you can obtain these from. I have never been successful, but then, I have the original hardcopy and so my motivation has been low. The patent number is 5,304,746 and it is currently in force, to the extent that I have millions of dollars just waiting to be spent on lawyers to enforce it.
So read on and enjoy,
Bud
(original post that above was inserted into follows)
Just in case you folks would like to step outside of the normal mass loaded cone termination regimen, please read this.
http://www.positive-feedback.com/Issue21/standingwaves.htm
The entire process was developed on a pair of Ohm F's and turned them into point source radiators, in a spherical sense. Also eliminated the reflections from the materials joints.
Bud
_______________________
Moderator Note:
The beginnings of this thread -- the 1st 68 posts have been copied out of 3 other threads.
Beyond the Ariel
OHM Acoustics "Walsh F" Speaker remakes
Help me kill a fostex artifact.
If some of the comments don't make sense it will be because they are out of their original context

_______________________
Hi All,
This is the beginning of a rather curious post. I have been bouncing around a few threads saying speculative sounding things about a speaker driver and associated baffle surfaces treatment, that does not look feasible, on first approach.
A moderator has agreed to create this thread, that has all of the pogo-ing posts in one place so everyone can doubt at once.
What I am portraying in these posts is a concept for controlling edged and smooth taper terminus zones. These zones are responsible for the bulk of what is wrong with modern drivers. They cause reflected standing waves, circulating Raleigh waves and diffractive emissions at the final terminus of a "speaker system". Almost all of these reflected artifacts are transient in nature. This means they do dissipate and without an extended dissipation period, due to particular materials used.
That their dissipation over time has a profoundly corrupting influence upon following sound energy and it's resultant reflections is quite obvious, when you get them to stop. What is not obvious is how pervasive the corruptions are. Speakers should theoretically provide infinite detail, complete with "musician applied color" and instrument induced transients and their resultant decays, all of them. Speakers should reproduce the sound field recorded, with enough spatial cues and time to arrival cues, to allow our millions of years old, audible threat assessment system, with it's semi autonomous correlator, to finish recreating the sonic event being reproduced with a fluency and ease that does not tire us nor force us try to hear beyond some irritating noise that interferes.
This EnABL process, portrayed in the following post series, does remove these transient artifacts, produced by uncontrolled reflections and refractions. This is not a theory. It works. It is also so good at this removal that it will not seem possible, for someone who has not tried it themselves, to believe. The qualitative statements you will find, as the braver and more adventurous DIY'rs try it out, will simply not be creditable. "Nothing could be that good" will be the thought and nothing could be farther from the truth, either. There are levels of treatment, having to do with how much your skill at hearing corruptions has developed, and, how maniacal your activities are. But just the most rudimentary attempt will bring huge benefit to your reproduced sound. The real learning process, after a few treated speakers, will be in determining how much is enough.
I will be providing a guided tour through treating a pair of Lowther drivers. I know next to nothing about these speakers and their idiosyncratic sound, but I am certain to horrify those who are devoted to these devices. I apologize to you for this insult, but the person who owns the Lowther’s has asked politely and pretty forcefully that I proceed.
I will not be making any before and after Quantitative measurements. I am going to leave that to you folks who really do know what you are doing in that realm. Of course that means you will have to treat a set of drivers, or two, but I will not be upset about this. I will suggest that very little, of what is a profound qualitative improvement, is going to show up in the usual tests. At least that has been my experience, but, I am not qualified to do these tests anyway. You who must, should probably start qualifying the results of this process with a CSD plot.
There are two documents on line you can refer to.
The first is posted at Positive Feedback Online, Issue 21 at this url http://www.positive-feedback.com/Issue21/standingwaves.htm This will give you some ground to understand from and does provide a truncated CSD on a cone, "phenolic ring" tweeter at the end of the paper. Take special notice of the last pair of comparisons, this is what all of these words are in honor of.
The other is a patent document found at where ever you can obtain these from. I have never been successful, but then, I have the original hardcopy and so my motivation has been low. The patent number is 5,304,746 and it is currently in force, to the extent that I have millions of dollars just waiting to be spent on lawyers to enforce it.
So read on and enjoy,
Bud
(original post that above was inserted into follows)
Just in case you folks would like to step outside of the normal mass loaded cone termination regimen, please read this.
http://www.positive-feedback.com/Issue21/standingwaves.htm
The entire process was developed on a pair of Ohm F's and turned them into point source radiators, in a spherical sense. Also eliminated the reflections from the materials joints.
Bud