BudP said:
BudP
I was just reading your first post and on this subjet and I was feeling that something was not clear. Sometimes its my writing that is not enough precise (English is not my first language) . Now,I think that we are in sync.
Thanks for your offer for providing some test pattern for me to experiment with. I will definitively come back to you on this subject in approx. 2 months. I have in front of me some major renovation project at my place and I feel that all my weekends will be spent on this. But beware, my interest in this topic is growing each and every day. Maybe I will be able to make some Sonotube enclosure before the end of April and be ready before May hopefully.
Cheers
Utopix.
Mamboni,
I have always thought of them as a diffraction grating, but working with a vertical vector that is unusual in ordinary wave tank experiments, so, I had to modify my thinking just a bit.
We are both involved in this same process and using effectively the same tools, just arrayed differently and applied with different measures, same thoughts though. I am pretty sure that a combination of the two, along with treating both sides of the dome tweeter diaphragms with EnABL, will take your current 90% of the ohm model 5's performance and turn it into about 180%
I too wish I had some pictures of this earlier time in my life, especially one of Bill's face, the physicist friend, to show to you, when I asked him what he thought was going on.... a priceless memory I will carry to my grave.
Bud
I have always thought of them as a diffraction grating, but working with a vertical vector that is unusual in ordinary wave tank experiments, so, I had to modify my thinking just a bit.
We are both involved in this same process and using effectively the same tools, just arrayed differently and applied with different measures, same thoughts though. I am pretty sure that a combination of the two, along with treating both sides of the dome tweeter diaphragms with EnABL, will take your current 90% of the ohm model 5's performance and turn it into about 180%
I too wish I had some pictures of this earlier time in my life, especially one of Bill's face, the physicist friend, to show to you, when I asked him what he thought was going on.... a priceless memory I will carry to my grave.
Bud
EnABLE pattern?
BudP
I’ve been following this thread and am in the process of building the Mamboni speaker system -I’m still waiting on parts and time (just got back from vacation) to finish it. Correct me if I’m wrong--your idea is to stencil in rectangular patterns (EnABLE pattern) with some type of acrylic model paint using a calligraphy pen on or near the top and bottom of the speaker cone.
- Also, you stated that this process should be used on the cabinet itself. Where would you place it?
- Is there an EnABLE pattern straight line stencil for this?
- Are the triangles the same size no matter what size the drivers are?
- Would this work on a cylinder cabinet like the one mamboni used (post #32)
- Is the EnABLE pattern different for tweeters? What tweeters would this work on?
- Do you have stencil for the different sizes woofer?
- Would the constant movement of the cone over time make the acrylic come off?
- Would you be sharing more information on how to get and use the EnABLE pattern and what are the best speakers this process will work on?
- Do you have any pictures of pass projects that you could share?
You stated that you have a conventional system that easily outperforms the Ohm F in all categories. Could you explain more and share the plans on how to make them?
Thanks,
BudP
I’ve been following this thread and am in the process of building the Mamboni speaker system -I’m still waiting on parts and time (just got back from vacation) to finish it. Correct me if I’m wrong--your idea is to stencil in rectangular patterns (EnABLE pattern) with some type of acrylic model paint using a calligraphy pen on or near the top and bottom of the speaker cone.
- Also, you stated that this process should be used on the cabinet itself. Where would you place it?
- Is there an EnABLE pattern straight line stencil for this?
- Are the triangles the same size no matter what size the drivers are?
- Would this work on a cylinder cabinet like the one mamboni used (post #32)
- Is the EnABLE pattern different for tweeters? What tweeters would this work on?
- Do you have stencil for the different sizes woofer?
- Would the constant movement of the cone over time make the acrylic come off?
- Would you be sharing more information on how to get and use the EnABLE pattern and what are the best speakers this process will work on?
- Do you have any pictures of pass projects that you could share?
You stated that you have a conventional system that easily outperforms the Ohm F in all categories. Could you explain more and share the plans on how to make them?
Thanks,
Whew.....
R Jamm,
You have the general plan correct and the pens have been my only means of applying the EnABL process in the past.
c2cthomas and I are collaborating on a stenciling method to replace the pen applied method for many applications. These stencil's will be available, in some DIY usable fashion, pretty quickly. We have plans and methods and even media trials in the works. If we are successfull you will have stencils that are designed for whatever woofer you are going to use.
This is planned with the thought of using Mamboni's felt triangles on the inside of the cone. I am pretty certain that this combo will be ultimately superior to the EnABL process alone. When both sides of a cone are treated with EnABL the cone becomes very transparent to back wave signals, emitting right through the cone and into the listening area. The EnABL process enforces a phase and time coherent wave structure to emitted information and that sort of energy is very good at remaining coherent, regardless of obstructions.
Using the Mamboni process right where he uses it now will help eliminate that possibility and still provide the needed "infinite" cone edge termination to the back side of the driver that allows the EnABL process to completely control the front side information emissions.
Just like the EnABL pattern blocks the Mamboni triangles probably should increase and decrease with the size of the cone they are applied to. I do not know if Mamboni has a rigorous analysis of this size change and I am not at all sure how much change is correct. We will all find out as we go along. I would personally scale the triangles in size, up or down, from his proven concept size found on the 10" woofers he is advocating using.
I would place the linear patten of EnABL blocks down the length of the tube, on opposite sides with a vector between the opposite lines at right angles to the listening area. This will attach all information expression from the tubes to this plane and will likely provide you with the leading edge of the perceived sound field too. I do this with ordinary cabinets, placing the pattern lines vertically, in the middle of the front to back dimension of, and down, all four of the sides. This helps to eliminate the entire speaker system as a perceivable sound source and in my system the speakers are sonically invisible regardless of where you sit, just like Ohm F's are.
I have never had the pattern made with acrylic paint delaminate or shed. I have had the conformal coat acrylic delaminate from the polypropylene surface of the Dynavox woofers in two half round areas, one on each woofer and about a 1/4" diameter. The coating has not come off nor has it altered the sound. It just lifted enough to show at these two places. This is the only event like this I have witnessed and because of it I now "tooth" the surface of plastic cones with 1000 grit sandpaper before applying the pattern and conformal coating. I do not think this will be needed on any other cone, dome, flat ribbon or horn flare material.
All speakers are the best for EnABL use. The process does NOT alter the speakers inherent qualities. As far as engineering concerns go the speaker just acts more like a theoretically perfect model would. I have applied the process to every type of speaker made and find that, while all of them share a clarity of detail, a hugeness and coherence of projected sound field, and, an uncanny rendition of musical colors and musician imposed emphasis, some manufacturers provide products that are just more interesting than others. Vifa, peerless, dynavox, seas, morrel and many others manufacturers drivers have been treated.
From that sort of list, my current system uses:
a 9.375" dynavox polycone woofer with a huge voice coil and a dis-assemble-able basket structure, that allows treatment on both sides of the entire cone surface.
a 6" dia Vifa dome midrange, with the inner perforated metal dome removed, the backing plate holes cut to one hole, the size of the magnet structure pass through hole. A very small back chamber (.4 liter as opposed to the 1.6 liter suggested) made from an ABS pipe end cap, stuffed with long fiber natural cotton that also extends up through the center magnet hole to form a small dome, trapped by a large opening plastic wire mesh.
two Radio Shack/Linnaeum polycarbonate leaf tweeters
a single Pioneer piezo film, half of a can shaped super tweeter, with the fine mesh grill removed.
All of the drivers and their mounting plate surfaces on the visible side have been treated with both the EnABL pattern and conformal coat material. Except for the Pioneer driver all of them have also had the EnABL pattern and conformal coating applied to the backside of the drivers. The pattern is not noticeable unless you look very closely but the very shiny surface of the conformal coat is quite noticeable.
On the Linnaeum and Pioneer tweeters only the pattern areas have been coated with the conformal coating. The dynavox woofer has a VERY thick coating, at least 10 mils, of the conformal coating just to construct a semblance of a boundary layer that will interact with the surrounding air. Otherwise it would be very clear and very dead sounding. As of now it matches the "speed" of the rest of the drivers exactly.
The system is sort of flat from 33 Hz to what ever the cut off for the Pioneer is. I am not as concerned with fractional octave to octave flatness as I am with phase coherence at the crossover points of 800 Hz, 4 kHz and a 0.22 mfd induced slope for the Pioneer tweeter. The entire tweeter assembly is impedance matched through a transformer, the design and manufacture of that sort of audio device is my livelihood, with a 2.8 db cut in turns matching ratio.
I can post a finished picture if anyone is interested, but it is not really impressive, until you turn them on and hear an orchestra embedded 50 feet into the back wall and from edge to edge and floor to ceiling of the room, without any hint of Hi Fi sound characteristic and seemingly infinite detail. Very nice to listen to, so long as I am not experimenting with new audio transformers that are not fully charged, or new DIY Litz wire audio cables, or the eternally demented "electron traps" I have been applying to the ground sides of all of my components, since discovering their characteristics.
Bud
R Jamm,
You have the general plan correct and the pens have been my only means of applying the EnABL process in the past.
c2cthomas and I are collaborating on a stenciling method to replace the pen applied method for many applications. These stencil's will be available, in some DIY usable fashion, pretty quickly. We have plans and methods and even media trials in the works. If we are successfull you will have stencils that are designed for whatever woofer you are going to use.
This is planned with the thought of using Mamboni's felt triangles on the inside of the cone. I am pretty certain that this combo will be ultimately superior to the EnABL process alone. When both sides of a cone are treated with EnABL the cone becomes very transparent to back wave signals, emitting right through the cone and into the listening area. The EnABL process enforces a phase and time coherent wave structure to emitted information and that sort of energy is very good at remaining coherent, regardless of obstructions.
Using the Mamboni process right where he uses it now will help eliminate that possibility and still provide the needed "infinite" cone edge termination to the back side of the driver that allows the EnABL process to completely control the front side information emissions.
Just like the EnABL pattern blocks the Mamboni triangles probably should increase and decrease with the size of the cone they are applied to. I do not know if Mamboni has a rigorous analysis of this size change and I am not at all sure how much change is correct. We will all find out as we go along. I would personally scale the triangles in size, up or down, from his proven concept size found on the 10" woofers he is advocating using.
I would place the linear patten of EnABL blocks down the length of the tube, on opposite sides with a vector between the opposite lines at right angles to the listening area. This will attach all information expression from the tubes to this plane and will likely provide you with the leading edge of the perceived sound field too. I do this with ordinary cabinets, placing the pattern lines vertically, in the middle of the front to back dimension of, and down, all four of the sides. This helps to eliminate the entire speaker system as a perceivable sound source and in my system the speakers are sonically invisible regardless of where you sit, just like Ohm F's are.
I have never had the pattern made with acrylic paint delaminate or shed. I have had the conformal coat acrylic delaminate from the polypropylene surface of the Dynavox woofers in two half round areas, one on each woofer and about a 1/4" diameter. The coating has not come off nor has it altered the sound. It just lifted enough to show at these two places. This is the only event like this I have witnessed and because of it I now "tooth" the surface of plastic cones with 1000 grit sandpaper before applying the pattern and conformal coating. I do not think this will be needed on any other cone, dome, flat ribbon or horn flare material.
All speakers are the best for EnABL use. The process does NOT alter the speakers inherent qualities. As far as engineering concerns go the speaker just acts more like a theoretically perfect model would. I have applied the process to every type of speaker made and find that, while all of them share a clarity of detail, a hugeness and coherence of projected sound field, and, an uncanny rendition of musical colors and musician imposed emphasis, some manufacturers provide products that are just more interesting than others. Vifa, peerless, dynavox, seas, morrel and many others manufacturers drivers have been treated.
From that sort of list, my current system uses:
a 9.375" dynavox polycone woofer with a huge voice coil and a dis-assemble-able basket structure, that allows treatment on both sides of the entire cone surface.
a 6" dia Vifa dome midrange, with the inner perforated metal dome removed, the backing plate holes cut to one hole, the size of the magnet structure pass through hole. A very small back chamber (.4 liter as opposed to the 1.6 liter suggested) made from an ABS pipe end cap, stuffed with long fiber natural cotton that also extends up through the center magnet hole to form a small dome, trapped by a large opening plastic wire mesh.
two Radio Shack/Linnaeum polycarbonate leaf tweeters
a single Pioneer piezo film, half of a can shaped super tweeter, with the fine mesh grill removed.
All of the drivers and their mounting plate surfaces on the visible side have been treated with both the EnABL pattern and conformal coat material. Except for the Pioneer driver all of them have also had the EnABL pattern and conformal coating applied to the backside of the drivers. The pattern is not noticeable unless you look very closely but the very shiny surface of the conformal coat is quite noticeable.
On the Linnaeum and Pioneer tweeters only the pattern areas have been coated with the conformal coating. The dynavox woofer has a VERY thick coating, at least 10 mils, of the conformal coating just to construct a semblance of a boundary layer that will interact with the surrounding air. Otherwise it would be very clear and very dead sounding. As of now it matches the "speed" of the rest of the drivers exactly.
The system is sort of flat from 33 Hz to what ever the cut off for the Pioneer is. I am not as concerned with fractional octave to octave flatness as I am with phase coherence at the crossover points of 800 Hz, 4 kHz and a 0.22 mfd induced slope for the Pioneer tweeter. The entire tweeter assembly is impedance matched through a transformer, the design and manufacture of that sort of audio device is my livelihood, with a 2.8 db cut in turns matching ratio.
I can post a finished picture if anyone is interested, but it is not really impressive, until you turn them on and hear an orchestra embedded 50 feet into the back wall and from edge to edge and floor to ceiling of the room, without any hint of Hi Fi sound characteristic and seemingly infinite detail. Very nice to listen to, so long as I am not experimenting with new audio transformers that are not fully charged, or new DIY Litz wire audio cables, or the eternally demented "electron traps" I have been applying to the ground sides of all of my components, since discovering their characteristics.
Bud
Source of Colorations
Stored energy grossly degrades the sense of realism in every way: it steals dynamics, compresses and distorts the soundstage (which is why I always audition in stereo), and almost flattens the sense of depth completely. It's like MP3 with extra colorations thrown in free.
Unfortunately, there are many many sources of stored energy, particularly in the first few critical milliseconds. Cabinets have standing waves and wall flexing, horns have significant diffraction at the horn mouth (which then travels back down the throat and reflects off the phase plug), and worst of all, cabinet damping materials don't really work well below 500 Hz. All this is quite audible, particularly when you hear the coloration go away. This kind of coloration is the kind of thing you notice in the first few seconds of listening - and we only tolerate it because that's how 99.999% of speakers sound, and have always sounded since the Twenties.
Electrostats store energy too, although far less than direct-radiators in boxes or any horn. Where the electrostat falls down are a series of small mylar-diaphragm resonances between 3 and 10 kHz, which is noticeable on a MLS waterfall measurement (although easily confused by different arrival times from different parts of the diaphragm).
All drivers fall down here, compared to what can be done with plasma drivers. In my experience - speaking for right now, anyway - cabinet colorations are considerably worse than driver colorations, at least with decent-quality modern drivers. With an old-school driver like the Altec 604 Duplex, OK, I doubt that cabinets make a lot of difference. But when coloration levels go down, cabinet coloration becomes much more noticeable, and is very difficult to reduce. Exotic cabinet materials really only help a little bit, and introduce odd new colorations of their own. (It takes magazine reviewers several years to realize a new type of coloration has been introduced.)
As for new drivers, well, I've tried getting OEM Tannoys for many years, with no luck. As far as I can tell, Tannoy only wants to sell complete systems, without the nuisance-factor of the DIY market. Can't say I blame them. So I'm looking at prosound folks like 18Sound, B&C, and Beyma.
Cloth Ears said:
Stored energy grossly degrades the sense of realism in every way: it steals dynamics, compresses and distorts the soundstage (which is why I always audition in stereo), and almost flattens the sense of depth completely. It's like MP3 with extra colorations thrown in free.
Unfortunately, there are many many sources of stored energy, particularly in the first few critical milliseconds. Cabinets have standing waves and wall flexing, horns have significant diffraction at the horn mouth (which then travels back down the throat and reflects off the phase plug), and worst of all, cabinet damping materials don't really work well below 500 Hz. All this is quite audible, particularly when you hear the coloration go away. This kind of coloration is the kind of thing you notice in the first few seconds of listening - and we only tolerate it because that's how 99.999% of speakers sound, and have always sounded since the Twenties.
Electrostats store energy too, although far less than direct-radiators in boxes or any horn. Where the electrostat falls down are a series of small mylar-diaphragm resonances between 3 and 10 kHz, which is noticeable on a MLS waterfall measurement (although easily confused by different arrival times from different parts of the diaphragm).
All drivers fall down here, compared to what can be done with plasma drivers. In my experience - speaking for right now, anyway - cabinet colorations are considerably worse than driver colorations, at least with decent-quality modern drivers. With an old-school driver like the Altec 604 Duplex, OK, I doubt that cabinets make a lot of difference. But when coloration levels go down, cabinet coloration becomes much more noticeable, and is very difficult to reduce. Exotic cabinet materials really only help a little bit, and introduce odd new colorations of their own. (It takes magazine reviewers several years to realize a new type of coloration has been introduced.)
As for new drivers, well, I've tried getting OEM Tannoys for many years, with no luck. As far as I can tell, Tannoy only wants to sell complete systems, without the nuisance-factor of the DIY market. Can't say I blame them. So I'm looking at prosound folks like 18Sound, B&C, and Beyma.
Those of you who are thinking seriously about this speaker format might want to read another thread also, assuming you haven't already.
I start you off where the ultra low storage termination information begins and there are two very different methods for perfectly terminating a big driver without a bunch of storage mass.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=30689&perpage=10&pagenumber=7
And yes this is a thread here in DIY
Bud
I start you off where the ultra low storage termination information begins and there are two very different methods for perfectly terminating a big driver without a bunch of storage mass.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=30689&perpage=10&pagenumber=7
And yes this is a thread here in DIY
Bud
Here's Bud's EnABL Paper & the Mamboni Mods
Over at Positive Feedback magazine, my old stomping ground back when I lived in Portland.
As mentioned in earlier posts, the smoothness of the rolloff region is CRITICAL for high-quality sound, as well as a well-behaved radiation pattern in the crossover region. The EnABL treatment might be especially important for pro-grade coax drivers, which from the published curves have real challenges in the rolloff region (2 to 10 kHz).
The thread by Mamboni elsewhere in the forum about the Ohm F also some interesting felt-strip treatments for modern 10" woofers, allowing them to act as Walsh bending-mode transducers up to 10 kHz.
Both techniques would be useful for chasing out those nasty peaks and ripples in the 2 to 10 kHz region, and would certainly improve the sound of a coax driver. With dipoles free of box colorations, yes, you'll hear even small improvements in the driver.
Over at Positive Feedback magazine, my old stomping ground back when I lived in Portland.
As mentioned in earlier posts, the smoothness of the rolloff region is CRITICAL for high-quality sound, as well as a well-behaved radiation pattern in the crossover region. The EnABL treatment might be especially important for pro-grade coax drivers, which from the published curves have real challenges in the rolloff region (2 to 10 kHz).
The thread by Mamboni elsewhere in the forum about the Ohm F also some interesting felt-strip treatments for modern 10" woofers, allowing them to act as Walsh bending-mode transducers up to 10 kHz.
Both techniques would be useful for chasing out those nasty peaks and ripples in the 2 to 10 kHz region, and would certainly improve the sound of a coax driver. With dipoles free of box colorations, yes, you'll hear even small improvements in the driver.
It Gets Better
Further on in the Ohm F thread, Bud and Mamboni start collaborating together on combining the techniques. Following this thread to the end makes for some VERY interesting reading on sound propagation through solid materials and methods to control standing waves.
The Bud/Mamboni techniques are especially useful for any dipole speaker - once again, because these designs are entirely free of cabinet coloration, so you can hear the driver as as they really are. Yes, I guess you could combine a dipole with a Walsh - maybe if the baffle were slanted or curved towards the top - but you guys are on your own here. I still want to explore a really good coax - and yeah, not too many of these - on a dipole baffle.
Further on in the Ohm F thread, Bud and Mamboni start collaborating together on combining the techniques. Following this thread to the end makes for some VERY interesting reading on sound propagation through solid materials and methods to control standing waves.
The Bud/Mamboni techniques are especially useful for any dipole speaker - once again, because these designs are entirely free of cabinet coloration, so you can hear the driver as as they really are. Yes, I guess you could combine a dipole with a Walsh - maybe if the baffle were slanted or curved towards the top - but you guys are on your own here. I still want to explore a really good coax - and yeah, not too many of these - on a dipole baffle.
C2Cthomas,
We're waiting...........
I have attached a pic of how to treat a typical Walsh dome style tweeter and deflection plate with the EnABL process. Had to go digging in really old patent papers to find it too....
Mamboni
Our processes are being talked over, in another thread, quite unrelated to this one and by one of the most famous of all DIY proponents.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=98969
We should join in and drag ole Thomas himself with us.
Bud
We're waiting...........
I have attached a pic of how to treat a typical Walsh dome style tweeter and deflection plate with the EnABL process. Had to go digging in really old patent papers to find it too....
Mamboni
Our processes are being talked over, in another thread, quite unrelated to this one and by one of the most famous of all DIY proponents.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=98969
We should join in and drag ole Thomas himself with us.
Bud
Hi Lynn,
When I asked about the potential benefits of "speeding up" a front side surface, as opposed to the back side, I was thinking about the Mamboni process of small triangular light felt necklaces applied at the cone terminus, on the back side, just as he does now for the Walsh style woofer drivers, and the EnABL process on the front side. Using a conformal coating that will transmit boundary layer energy faster than the speed of sound through air will allow a fairly large increase in useful emitting surface when the EnABL pattern is underneath it to kill the transient standing waves. The three together seemed likely to be beneficial here in dipole land.
I am going to assume, without ANY proof that the Mamboni process on the back side will allow us to naturally bend the null zone back like a skirt and if we provide a skirt plate for those waves to attach to we could probably shape the entire dipole emission into the room with that lever.
Do not count the Walsh bending event out with respect to dipole emission either. When EnABL treated, the things emit as true point source radiators, right up and over the magnets if those surfaces have also been eliminated as diffraction edges. Scary looking in a living room filled with wife... anyway.
I am also interested in a Walsh style upper mid and tweeter in combination with a modified dipole emission lower mid and bass driver setup. That led me to question whether any of our participants had investigated sounding board shapes other than the usual straight edged planar surface. I have seen one interesting one, from the land of OZ participants, that shares its perimeter shape with that of musical instruments. I wonder if that French Curve derived edge treatment helps to kill transient standing waves. Seems likely to me. See BobF's pics here.
http://home.vicnet.net.au/~macinc/clubproj.htm
Bud
When I asked about the potential benefits of "speeding up" a front side surface, as opposed to the back side, I was thinking about the Mamboni process of small triangular light felt necklaces applied at the cone terminus, on the back side, just as he does now for the Walsh style woofer drivers, and the EnABL process on the front side. Using a conformal coating that will transmit boundary layer energy faster than the speed of sound through air will allow a fairly large increase in useful emitting surface when the EnABL pattern is underneath it to kill the transient standing waves. The three together seemed likely to be beneficial here in dipole land.
I am going to assume, without ANY proof that the Mamboni process on the back side will allow us to naturally bend the null zone back like a skirt and if we provide a skirt plate for those waves to attach to we could probably shape the entire dipole emission into the room with that lever.
Do not count the Walsh bending event out with respect to dipole emission either. When EnABL treated, the things emit as true point source radiators, right up and over the magnets if those surfaces have also been eliminated as diffraction edges. Scary looking in a living room filled with wife... anyway.
I am also interested in a Walsh style upper mid and tweeter in combination with a modified dipole emission lower mid and bass driver setup. That led me to question whether any of our participants had investigated sounding board shapes other than the usual straight edged planar surface. I have seen one interesting one, from the land of OZ participants, that shares its perimeter shape with that of musical instruments. I wonder if that French Curve derived edge treatment helps to kill transient standing waves. Seems likely to me. See BobF's pics here.
http://home.vicnet.net.au/~macinc/clubproj.htm
Bud
ScottG,
I did apply that EnABL pattern to a set of horns once..... To some Radio Shack systems with a high efficiency 15 inch woofer, a mid and a tweeter horn, not time aligned in any sense. The untreated speakers were not much fun to listen to.
The cone, front plate and horns were all treated. The results were odd.
The result was a VERY forceful speaker with razor sharp detail and near perfect time alignment, as the EnABL pattern appeared to enforce this condition onto the overall sound, even though all of the drivers were mounted flush with the front cabinet surface.
Did not make them any more pleasant to listen to though, but they were a lot more efficient and would play quite a bit louder than before so their new owner was very happy.
Did this for some teen owned boom boxes too, with the same results, but was always worried I would have to face the irate townspeople with their pitch forks and torches so I stopped doing that. Then the cars full of woofers and amps began to show up and I knew I was again safe.
Bud
I did apply that EnABL pattern to a set of horns once..... To some Radio Shack systems with a high efficiency 15 inch woofer, a mid and a tweeter horn, not time aligned in any sense. The untreated speakers were not much fun to listen to.
The cone, front plate and horns were all treated. The results were odd.
The result was a VERY forceful speaker with razor sharp detail and near perfect time alignment, as the EnABL pattern appeared to enforce this condition onto the overall sound, even though all of the drivers were mounted flush with the front cabinet surface.
Did not make them any more pleasant to listen to though, but they were a lot more efficient and would play quite a bit louder than before so their new owner was very happy.
Did this for some teen owned boom boxes too, with the same results, but was always worried I would have to face the irate townspeople with their pitch forks and torches so I stopped doing that. Then the cars full of woofers and amps began to show up and I knew I was again safe.
Bud
In another thread Janneman has taken the lot of us to task for not understanding the operating principles that are the basis for a true Walsh driver and our explorations into them.
See here: http://www.diyaudio.com/forums/showthread.php?s=&threadid=99138&perpage=10&pagenumber=10
For my part, I agree that we should give more reverence to Lincoln Walsh's groundbreaking insights.
In fact all drivers work within the parameters that Mr Walsh provided. No driver is a "piston" at any time other than it's single natural frequency of mass resonance. All other frequencies are produced as some form of bending wave.
Below the "pistonic moment" frequency the drivers are literally flapping, like a wet sheet in a wind storm, the energy into the surrounding air. As their bending length becomes an ever decreasing fraction of the wave length they are creating they are able to bend less energy into a compression wave and become less efficient.
This is a bending line length VS frequency problem, not a cone piston movement problem. Walsh, with the help of OHM corp. solved this issue with a tall cylinder with an exceptionally long bending line VS it's diameter. The OHM F and A were notable for how much "information" was contained in their low frequency performance. The result of bending the very low frequencies into the surrounding air in a much less compromised phase and time signature format, with respect to the shorter waves also bending into the environment
Above the pistonic point waves also bend into the environment but it is a ripple with a period length less than the bending line length of the driver. As Ohm discovered, a more bending compliant material was required to allow this ripple to create a pressure wave in adjacent air, remain in phase with the pistonic and lower frequencies and still provide enough lateral stiffness to physically enforce true pistonic movement and drive lower frequency, fractional wave, bending into the environment. Hence their use of stepped materials, an initial titanium cone, a follow on aluminum cone and a final paper cone with mass loaded termination slots cut into the paper and filled with an RTV compound. The type A was all metal in construction.
I do not know who did the actual empirical extrapolation of Walsh's theory into an engineered device, but their solutions were brilliant and their mentation was utterly without boundaries.
As for the two termination schemes found in this thread, both work within Wash's theories and both will provide a superior termination to a Walsh derived bending line, or, the more typical short bending line, pistonic theory, speaker driver construction.
The only lack I find in either Walsh's theory or Ohm's implementation is a misunderstanding of the mechanism by which energy travels through a permeable medium, regardless of which side of the pistonic moment it resides on. Please go here and read this for a much deeper treatise on this topic.
http://www.positive-feedback.com/Issue21/standingwaves.htm
Mr Walsh did not look closely enough at this aspect, that since boundary layer physics sprouted in the late 80's, is now called "boundary layer phenomena". I suspect that he was aware of the event, but either did not comprehend it's potential importance to the expression of his theories, or was concerned that a discussion of such a heretical concept, in concert with his already deeply heretical bending line concept was not going to be beneficial to acceptance of his ideas.
It is a shame because had the Walsh / Ohm F's been terminated with a device that actually controlled the boundary layer emitting surface of the bending line driver, the Ohm F and follow on speakers would be a far larger force than we now see.
Thank you Lincoln Walsh, EnABL would not exist if it were not for you. And, thank you OHM and attendant engineers, without you I would not have had a platform upon which to develop the EnABL process.
Which, by the way, works on drivers that try to conform to the pistonic model precisely because they are Walsh bending line drivers and only pistonic at one single frequency.
Mamaboni's discoveries also are a superior termination scheme because they take into account the termination requirements of a Walsh bending line and a third vector boundary layer that emits while the wave front crosses that bending line. They work on pistonic based drivers for exactly the same reason mine do. Lincoln Walsh was and still is correct in his upset of the pistonic apple cart.
Bud
See here: http://www.diyaudio.com/forums/showthread.php?s=&threadid=99138&perpage=10&pagenumber=10
For my part, I agree that we should give more reverence to Lincoln Walsh's groundbreaking insights.
In fact all drivers work within the parameters that Mr Walsh provided. No driver is a "piston" at any time other than it's single natural frequency of mass resonance. All other frequencies are produced as some form of bending wave.
Below the "pistonic moment" frequency the drivers are literally flapping, like a wet sheet in a wind storm, the energy into the surrounding air. As their bending length becomes an ever decreasing fraction of the wave length they are creating they are able to bend less energy into a compression wave and become less efficient.
This is a bending line length VS frequency problem, not a cone piston movement problem. Walsh, with the help of OHM corp. solved this issue with a tall cylinder with an exceptionally long bending line VS it's diameter. The OHM F and A were notable for how much "information" was contained in their low frequency performance. The result of bending the very low frequencies into the surrounding air in a much less compromised phase and time signature format, with respect to the shorter waves also bending into the environment
Above the pistonic point waves also bend into the environment but it is a ripple with a period length less than the bending line length of the driver. As Ohm discovered, a more bending compliant material was required to allow this ripple to create a pressure wave in adjacent air, remain in phase with the pistonic and lower frequencies and still provide enough lateral stiffness to physically enforce true pistonic movement and drive lower frequency, fractional wave, bending into the environment. Hence their use of stepped materials, an initial titanium cone, a follow on aluminum cone and a final paper cone with mass loaded termination slots cut into the paper and filled with an RTV compound. The type A was all metal in construction.
I do not know who did the actual empirical extrapolation of Walsh's theory into an engineered device, but their solutions were brilliant and their mentation was utterly without boundaries.
As for the two termination schemes found in this thread, both work within Wash's theories and both will provide a superior termination to a Walsh derived bending line, or, the more typical short bending line, pistonic theory, speaker driver construction.
The only lack I find in either Walsh's theory or Ohm's implementation is a misunderstanding of the mechanism by which energy travels through a permeable medium, regardless of which side of the pistonic moment it resides on. Please go here and read this for a much deeper treatise on this topic.
http://www.positive-feedback.com/Issue21/standingwaves.htm
Mr Walsh did not look closely enough at this aspect, that since boundary layer physics sprouted in the late 80's, is now called "boundary layer phenomena". I suspect that he was aware of the event, but either did not comprehend it's potential importance to the expression of his theories, or was concerned that a discussion of such a heretical concept, in concert with his already deeply heretical bending line concept was not going to be beneficial to acceptance of his ideas.
It is a shame because had the Walsh / Ohm F's been terminated with a device that actually controlled the boundary layer emitting surface of the bending line driver, the Ohm F and follow on speakers would be a far larger force than we now see.
Thank you Lincoln Walsh, EnABL would not exist if it were not for you. And, thank you OHM and attendant engineers, without you I would not have had a platform upon which to develop the EnABL process.
Which, by the way, works on drivers that try to conform to the pistonic model precisely because they are Walsh bending line drivers and only pistonic at one single frequency.
Mamaboni's discoveries also are a superior termination scheme because they take into account the termination requirements of a Walsh bending line and a third vector boundary layer that emits while the wave front crosses that bending line. They work on pistonic based drivers for exactly the same reason mine do. Lincoln Walsh was and still is correct in his upset of the pistonic apple cart.
Bud
Hi Bud,
I'm curious about your system (post #112). I don't want to hijack this thread, but could you elaborate a bit more on it? Specifically, what were your performance goals and what is/are important/necessary qualities for your speakers to reproduce.
Your description of the sound of your system is very similar to Lynn's description of how a system sounds at the highest level. And yes, please post a picture. Thank you.
I'm curious about your system (post #112). I don't want to hijack this thread, but could you elaborate a bit more on it? Specifically, what were your performance goals and what is/are important/necessary qualities for your speakers to reproduce.
Your description of the sound of your system is very similar to Lynn's description of how a system sounds at the highest level. And yes, please post a picture. Thank you.
ultrakaz,
Well, I have the same goals as Lynn, Romy the Cat, Island Pink, the moderators of this forum, you and very many others involved in DIY audio. I want a performance in my living room that satisfies my musical needs. I am used to extreme detail, correct depth of field, jubilant dynamic color as added by the musicians, a natural micro dynamic coherence and it's resultant stage setting for the musical event.
At the moment I am working on developing an amp and preamp of pretty simple circuit design and outstanding usefulness in developing audio transformers. The speakers have not changed in five years, except that I remounted the Linnaeum tweeters down on the speaker box and a recent trial addition of a Pioneer half can super tweeter, that may stay and may not.
I have recently discovered a method that allows me to uncover the back half of the musical notes, with the sort of clarity that the front half exhibits. This has added a depth of note decay and a coherence to chord structures in orchestras and piano's that I have not quite gotten used to yet.
Mostly I am just working towards a time when I have no further complaints with the equipment and I can explore the music I have collected, without constantly being distracted by my correlator warnings going off about this or that uncategorized and potentially dangerous noise.
I have to warn you, the speakers are not impressive looking. They were originally designed and built as workhorses, to allow me to audition the R&D from my transformer explorations. Just as the user adjustable dynamic color, true Litz wire, cables were invented, so I could listen for faults without having to worry about spurious cable colorations or loss of information content.
My contributions to this forum are meant to be a stepping stone for other people to use, so they might feel confident enough to explore and enjoy what this odd EnABL pattern brings to the reproduction of music, which is all I really care about
Bud
Well, I have the same goals as Lynn, Romy the Cat, Island Pink, the moderators of this forum, you and very many others involved in DIY audio. I want a performance in my living room that satisfies my musical needs. I am used to extreme detail, correct depth of field, jubilant dynamic color as added by the musicians, a natural micro dynamic coherence and it's resultant stage setting for the musical event.
At the moment I am working on developing an amp and preamp of pretty simple circuit design and outstanding usefulness in developing audio transformers. The speakers have not changed in five years, except that I remounted the Linnaeum tweeters down on the speaker box and a recent trial addition of a Pioneer half can super tweeter, that may stay and may not.
I have recently discovered a method that allows me to uncover the back half of the musical notes, with the sort of clarity that the front half exhibits. This has added a depth of note decay and a coherence to chord structures in orchestras and piano's that I have not quite gotten used to yet.
Mostly I am just working towards a time when I have no further complaints with the equipment and I can explore the music I have collected, without constantly being distracted by my correlator warnings going off about this or that uncategorized and potentially dangerous noise.
I have to warn you, the speakers are not impressive looking. They were originally designed and built as workhorses, to allow me to audition the R&D from my transformer explorations. Just as the user adjustable dynamic color, true Litz wire, cables were invented, so I could listen for faults without having to worry about spurious cable colorations or loss of information content.
My contributions to this forum are meant to be a stepping stone for other people to use, so they might feel confident enough to explore and enjoy what this odd EnABL pattern brings to the reproduction of music, which is all I really care about
Bud
ultrkaz,
Email me about the wires. Email c2cthomas about the Mamboni / EnABL treatment details.
The back half of the notes comes from having a method of preserving micro dynamic detail, the E Field portion of that detail, which becomes B Field. I do it by providing low threshold, dielectric dipole attached, sheet oriented electrons, on the ground plane. You can do this with poured ground planes and guite a lot of PCB varnish, or some huge stranded wires, 8 gauge or more and a measured amount of dielectric material both surrounding the wires and melted into them. You might even be able to use low threshold voltage Teflon, audio bipolar capacitors shorted to ground on both ends. What ever method you use will entail providing ground plane storage for an abundance of electrons so they do not return to service ground or further.
The research I have done on dielectrics in transformers, audio cables and now ground planes has shown me that while we have a very excellent handle on signal side electron manipulation we really have ignored the manipulation of the ground side signal of our equipment. I do have a solution, it is easy to apply, but it is very much applied voodoo physics.... more or less like the EnABL process is.... makes perfect sense after you understand how it works and why you might need it.
So, email me and we can talk about your interests.
Bud
Email me about the wires. Email c2cthomas about the Mamboni / EnABL treatment details.
The back half of the notes comes from having a method of preserving micro dynamic detail, the E Field portion of that detail, which becomes B Field. I do it by providing low threshold, dielectric dipole attached, sheet oriented electrons, on the ground plane. You can do this with poured ground planes and guite a lot of PCB varnish, or some huge stranded wires, 8 gauge or more and a measured amount of dielectric material both surrounding the wires and melted into them. You might even be able to use low threshold voltage Teflon, audio bipolar capacitors shorted to ground on both ends. What ever method you use will entail providing ground plane storage for an abundance of electrons so they do not return to service ground or further.
The research I have done on dielectrics in transformers, audio cables and now ground planes has shown me that while we have a very excellent handle on signal side electron manipulation we really have ignored the manipulation of the ground side signal of our equipment. I do have a solution, it is easy to apply, but it is very much applied voodoo physics.... more or less like the EnABL process is.... makes perfect sense after you understand how it works and why you might need it.
So, email me and we can talk about your interests.
Bud
dineubec,
Pretty neat stuff. I have had thoughts on this sort of speaker for years but knew better than to attempt so much precision wood work.
The EnABL process will work on all of the drivers and all of the surfaces but will be quite an undertaking to do. I would recommend that you finish first. Then begin to categorize what you do not find satisfactory in the actual audible performance. My method here is to start with the fundamentals first, up to 1 k or so and listen for inaccuracies in the left hand of piano's and all bowed and plucked strings larger than a violin. I will often deliberately reduce very low frequency performance at first just to help clarify what is actually going on.
What I listen for is a garble of tones, at any particular frequency. Once I am familiar with what I am hearing I add a higher frequency driver and listen to how it modifies what I am familiar with. This sort of listening teaches me what is incorrect in only one driver and what is a multi driver problem.
Were these my speakers I would use a Vifa 3" mid in place of the metal dome and phase screen. The EnABL process can not control "systemic" resonances, those caused by materials and physical obstructions used in driver construction. I think it likely that you will find a garble from that mid dome that is directly related to the material used and treating with EnABL will only make it more pronounced, because everything else will work better around that frequency band..
Does not mean that you should change your plans, you may have already worked around what ever difficulties this particular driver exhibits, and they all exhibit many problems.
The EnABL process will ease the transition off of the round to square baffle and likely can control those surfaces and force them into phase and time coherency. The tweeter would work well with the process but you will have to disassemble it and treat the backside of the dome also. Neither of the dome drivers can be treated with other than a pen and guide pattern process, at least from my experience.
I will post any other thoughts I have on your thread.
Bud
Pretty neat stuff. I have had thoughts on this sort of speaker for years but knew better than to attempt so much precision wood work.
The EnABL process will work on all of the drivers and all of the surfaces but will be quite an undertaking to do. I would recommend that you finish first. Then begin to categorize what you do not find satisfactory in the actual audible performance. My method here is to start with the fundamentals first, up to 1 k or so and listen for inaccuracies in the left hand of piano's and all bowed and plucked strings larger than a violin. I will often deliberately reduce very low frequency performance at first just to help clarify what is actually going on.
What I listen for is a garble of tones, at any particular frequency. Once I am familiar with what I am hearing I add a higher frequency driver and listen to how it modifies what I am familiar with. This sort of listening teaches me what is incorrect in only one driver and what is a multi driver problem.
Were these my speakers I would use a Vifa 3" mid in place of the metal dome and phase screen. The EnABL process can not control "systemic" resonances, those caused by materials and physical obstructions used in driver construction. I think it likely that you will find a garble from that mid dome that is directly related to the material used and treating with EnABL will only make it more pronounced, because everything else will work better around that frequency band..
Does not mean that you should change your plans, you may have already worked around what ever difficulties this particular driver exhibits, and they all exhibit many problems.
The EnABL process will ease the transition off of the round to square baffle and likely can control those surfaces and force them into phase and time coherency. The tweeter would work well with the process but you will have to disassemble it and treat the backside of the dome also. Neither of the dome drivers can be treated with other than a pen and guide pattern process, at least from my experience.
I will post any other thoughts I have on your thread.
Bud
BudP said:
Hmm, I'd like to hear more about this interesting material. Where do you get it, what is it named, etc. "Good from infrasonic to 2 kHz" sounds pretty awesome to me, and certainly good enough for the purposes of edge termination on the HF dipole and bass units.
Reflecting on the previous mini-essay, we see the same kind of topological tricks used in microphones to create the desired polar pattern. Omni mikes have small enclosed chambers on the back side of the diaphragm, dipoles are left open on both sides, and cardioids use damping techniques on the back side of the diaphragm - and for variable-pattern mikes, anything from variable shutters to two sets of diaphragms and an electrical adjustment.
The real issue is edge termination, regardless of enclosure type. Loudspeaker designers who avoid the time domain like to dance around this, but I now think it's a combination of mind-set (freq resp uber alles), unwillingness to work in another domain, and unfamiliarity with the tools of the time domain - MLS, TDS, etc. The frequency-only mindset has significantly retarded progress in loudspeaker design over many decades - I can now understand better why Dick Heyser of Cal Tech met nothing but 100% opposition in his native Los Angeles, the home of Altec, JBL, and Cerwin-Vega. His work met a more receptive audience in the UK and Europe, but I'm still surprised how alien working in the time domain is for many high-end designers.
When you visualize the driver as a wideband pulse-emitting device with a dipolar radiation pattern, it's easier to see what the enclosure is really doing - storing and re-radiating energy. There are two things making this challenging relative to other fields: the awkward requirement for three decades of bandwidth - extraordinarily wide by RF standards - and the extreme dynamic range of the ear, which is very sensitive to the faintest decay products. The only reason we don't object more to the grossly artificial sound of hifi systems is we've been listening to these things for a long time.
Geoff,
May I suggest that you think about how you can get the energy off of the baffle plate without attenuating it, without mass "STORAGE" damping, without any ringing of transient standing waves, without any diffraction artifacts and in phase and time coherence with the expanding polar wave front from the driver. That will get you much farther than damping of any sort and I believe is the point Lynn has been pushing towards with his comments. Unless you have a "perfect" damping scheme you will have reflected energy.
You might also look at the thread on Walsh drivers for some interesting information on wave termination from a surface without damping.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=30689&perpage=10&pagenumber=5
For your phase plug concern I would personally urge you to make a smooth flat surface with a flat acrylic paint, or study and apply either the Mamboni or EnABL edge termination process, one will apply, and will satify your concerns.
Bud
May I suggest that you think about how you can get the energy off of the baffle plate without attenuating it, without mass "STORAGE" damping, without any ringing of transient standing waves, without any diffraction artifacts and in phase and time coherence with the expanding polar wave front from the driver. That will get you much farther than damping of any sort and I believe is the point Lynn has been pushing towards with his comments. Unless you have a "perfect" damping scheme you will have reflected energy.
You might also look at the thread on Walsh drivers for some interesting information on wave termination from a surface without damping.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=30689&perpage=10&pagenumber=5
For your phase plug concern I would personally urge you to make a smooth flat surface with a flat acrylic paint, or study and apply either the Mamboni or EnABL edge termination process, one will apply, and will satify your concerns.
Bud
JoninCR,
You might want to re-read the last few pages. They aren't actually about bass monopoles at all. Some cardioid bass was mentioned by Lynn, Gary Pimm's flat to 16 Hz system specifically, and then some slight discussion of how to use a specialized, infinite edge simulation pattern, with multiple, in this case likely hundreds, of ports in an attempt to make a perfectly terminated rear bass chamber for possible bipolar operation, as an alternate to the cardioid bass was also mentioned. I am not at all sure why more bass might be needed, Gary Pimm appears to have shown a clear path for integrating bass and bipolar mid and upper drivers.
Your point on the amount of power that is available at the null zone of a driver is important to note. There are some edge terminations that remove reflected energy from the cone edge, being experimented with in another thread here, the Walsh thread after page 6.
I can report that the EnABL process narrows the null zone at the periphery of a driver to just a handful of degrees. Would that help or hinder your damping procedure as shown in your pictures? This process will also eliminate edge diffraction from a baffle, regardless of it's shape, and even large radius edge contours can benefit from a less lossy termination.
The Mamboni process spoken of in earlier pages in this thread, will also remove edge diffraction by making the terminus infinite. The use of both of these tools to control driver and baffle plane reflections and energy storage, without significantly damping any of the active or passive surfaces with further energy storage mechanisms, might interest you in your future experiments.
Bud
You might want to re-read the last few pages. They aren't actually about bass monopoles at all. Some cardioid bass was mentioned by Lynn, Gary Pimm's flat to 16 Hz system specifically, and then some slight discussion of how to use a specialized, infinite edge simulation pattern, with multiple, in this case likely hundreds, of ports in an attempt to make a perfectly terminated rear bass chamber for possible bipolar operation, as an alternate to the cardioid bass was also mentioned. I am not at all sure why more bass might be needed, Gary Pimm appears to have shown a clear path for integrating bass and bipolar mid and upper drivers.
Your point on the amount of power that is available at the null zone of a driver is important to note. There are some edge terminations that remove reflected energy from the cone edge, being experimented with in another thread here, the Walsh thread after page 6.
I can report that the EnABL process narrows the null zone at the periphery of a driver to just a handful of degrees. Would that help or hinder your damping procedure as shown in your pictures? This process will also eliminate edge diffraction from a baffle, regardless of it's shape, and even large radius edge contours can benefit from a less lossy termination.
The Mamboni process spoken of in earlier pages in this thread, will also remove edge diffraction by making the terminus infinite. The use of both of these tools to control driver and baffle plane reflections and energy storage, without significantly damping any of the active or passive surfaces with further energy storage mechanisms, might interest you in your future experiments.
Bud
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