Mamboni -
In your drawing for the variovent you speck a 3/4 inch circular cutout of the speaker dome covered with 3 layers of felt. In post #38 you mention that the cutout for the vent is 1/2 inch. I'm at a bit of a loss - can you clear this up? Also - what are the diameters would you speck for the three layers of felt? Your drawing looks like 1 1/4 inch, 1 1/2 inch, 1 3/4 inch, diameters were used - would this be correct - or would these work?
In your drawing for the variovent you speck a 3/4 inch circular cutout of the speaker dome covered with 3 layers of felt. In post #38 you mention that the cutout for the vent is 1/2 inch. I'm at a bit of a loss - can you clear this up? Also - what are the diameters would you speck for the three layers of felt? Your drawing looks like 1 1/4 inch, 1 1/2 inch, 1 3/4 inch, diameters were used - would this be correct - or would these work?
Well - need to press on and get some things done - so jumping right in with the Mamboni mod's to the Pioneer 10 inch as specked in his drawings. BudP is a jumping up and down (in a good way) for me to finish my speakers and do some listening test. 
I have to mod speaker #2 and prep it for the BudP's EnABL pattern, cut up another hunk of Sonotube and then carve up some MDF for the end caps and center brace. OH YEAH - WE'RE HAVING FUN NOW!!!
photo of 1st speaker with Mamboni magic!!
I have to mod speaker #2 and prep it for the BudP's EnABL pattern, cut up another hunk of Sonotube and then carve up some MDF for the end caps and center brace. OH YEAH - WE'RE HAVING FUN NOW!!!
photo of 1st speaker with Mamboni magic!!
Here's My Two Cents
Hey, Mr. Mamboni, here's a variant of the Mamboni Mod you might want to try:
Why not make the triangular felt strips different sizes? Specifically, I'd try 2 or 3 different sizes, ratioed in the Golden Section 1:1.618:2.618 ratios.
I'd also limit the biggest size triangles to no more than 3 or 5 pieces, and would avoid have the big ones in 4, 6, 8, or even numbers. This helps the cone avoid the symmetric breakup modes, while maintaining a degree of cone rigidity.
Hey, Mr. Mamboni, here's a variant of the Mamboni Mod you might want to try:
Why not make the triangular felt strips different sizes? Specifically, I'd try 2 or 3 different sizes, ratioed in the Golden Section 1:1.618:2.618 ratios.
I'd also limit the biggest size triangles to no more than 3 or 5 pieces, and would avoid have the big ones in 4, 6, 8, or even numbers. This helps the cone avoid the symmetric breakup modes, while maintaining a degree of cone rigidity.
c2cthomas said:Well - need to press on and get some things done - so jumping right in with the Mamboni mod's to the Pioneer 10 inch as specked in his drawings. BudP is a jumping up and down (in a good way) for me to finish my speakers and do some listening test.
I have to mod speaker #2 and prep it for the BudP's EnABL pattern, cut up another hunk of Sonotube and then carve up some MDF for the end caps and center brace. OH YEAH - WE'RE HAVING FUN NOW!!!
photo of 1st speaker with Mamboni magic!!
The size of the vent is not precise. I used 3/4 " dia. hole. The felt pieces, three in all, are large enough to cover the vent and have about 1/2" to 3/4" felt around the opeinig. So, the felt circles were about 1 3/4" inch diameter. The photo of the finished driver looks fantastic - very clean and uniform work.
Sure, different size triangles would spread the resononce modes more and could sound better - experimentation is good. I am anxious to hear yor impressions of the modified drivers with tweeter. Are you clear on the wiring?
Hi Mamboni!
I used your 1.5 inch sized equilateral triangles and varied the size of the felt pieces used on the dome assembly @ 1.75, 1.50, and 1.25 inches.
I assumed the hook up was going straight to the woofer + to + and - to - , and then from the + side of the woofer through the cap and 4 ohm resistor in series to the + side of the tweeter. Correct?
I'm working on an "Olsen" variation of your theme but I am concerned with edge reflection so I'm going to include BudP's EnABL pattern as well. The attached example uses "Golden Section" ( Fibonacci) section triangles and I have those placed - will add EnABL after I post.
I believe that your triangles serve as a torsion mechanism that damps the major cone flexing with a variable degree of mechanical resistance vs. frequency and that BudP's EnABL will act as a "trap" on frequencies reflected from the speaker edge by setting up an mechanical interference on the cone surface. Should be interesting!!
Glad I purchased an extra speaker to mess around with!
I used your 1.5 inch sized equilateral triangles and varied the size of the felt pieces used on the dome assembly @ 1.75, 1.50, and 1.25 inches.
I assumed the hook up was going straight to the woofer + to + and - to - , and then from the + side of the woofer through the cap and 4 ohm resistor in series to the + side of the tweeter. Correct?
I'm working on an "Olsen" variation of your theme but I am concerned with edge reflection so I'm going to include BudP's EnABL pattern as well. The attached example uses "Golden Section" ( Fibonacci) section triangles and I have those placed - will add EnABL after I post.
I believe that your triangles serve as a torsion mechanism that damps the major cone flexing with a variable degree of mechanical resistance vs. frequency and that BudP's EnABL will act as a "trap" on frequencies reflected from the speaker edge by setting up an mechanical interference on the cone surface. Should be interesting!!
Glad I purchased an extra speaker to mess around with!
microwalsh8504 said:Hello DIYers,
Another question is, has anyone tried to replicate there landmark speaker the Walsh F?
I was wondering if anyone was able to replicate this unusual design and make a speaker using the WALSH technology.
Thanks.
my first thought on seeing this-
http://www.diyaudio.com/forums/showthread.php?s=&threadid=99138&perpage=10&pagenumber=1
GRollins said:
6298
Well - until I can get around to learning how to make my own paper for cones I'll guess I'll be working on the Mamboni Walsh 5 remakes.
Cut down some more SonoTube today. It's pretty slow going cutting this stuff up with those little plastic knives tho - and you go through a bunch of 'em!! 
I'm making 3 speakers - two to keep and one as a "test-tube" to play with mod's on. Concerned with wall flex - but will address that at a later place and time. Might put one of those 14 inch babies inside an 18 inch tube and use some expandable foam between the walls to improve flex resistance and deaden things up a bit. Sounds a bit more practical than filling the base up with Jello pudding.
Anyone know where I can pick up one of those old quadraphonic units that were around in the 70's? Quad sound and an 8-track!
BudP would shoot me - most likely several times!
Cut down some more SonoTube today. It's pretty slow going cutting this stuff up with those little plastic knives tho
- and you go through a bunch of 'em!! I'm making 3 speakers - two to keep and one as a "test-tube" to play with mod's on. Concerned with wall flex - but will address that at a later place and time. Might put one of those 14 inch babies inside an 18 inch tube and use some expandable foam between the walls to improve flex resistance and deaden things up a bit. Sounds a bit more practical than filling the base up with Jello pudding.
Anyone know where I can pick up one of those old quadraphonic units that were around in the 70's? Quad sound and an 8-track!
BudP would shoot me - most likely several times!
c2cthomas said:Hi Mamboni!
I used your 1.5 inch sized equilateral triangles and varied the size of the felt pieces used on the dome assembly @ 1.75, 1.50, and 1.25 inches.
I assumed the hook up was going straight to the woofer + to + and - to - , and then from the + side of the woofer through the cap and 4 ohm resistor in series to the + side of the tweeter. Correct?
I'm working on an "Olsen" variation of your theme but I am concerned with edge reflection so I'm going to include BudP's EnABL pattern as well. The attached example uses "Golden Section" ( Fibonacci) section triangles and I have those placed - will add EnABL after I post.
I believe that your triangles serve as a torsion mechanism that damps the major cone flexing with a variable degree of mechanical resistance vs. frequency and that BudP's EnABL will act as a "trap" on frequencies reflected from the speaker edge by setting up an mechanical interference on the cone surface. Should be interesting!!
Glad I purchased an extra speaker to mess around with!
Yes, the woofer is wired straight from the amp. But, some suggestions:
I would wire the woofer (+) to the binding post (+) because although the woofer is firing down into the box and is actually 180 degrees out of phase vis-a-vis a forward firing woofer, the tweeter will be in correct phase.
I preferred the sound of the tweeter wired in what is opposite phase: woofer + terminal to tweeter (+) terminal. The woofer coil inductance is causing phase shift, and I believe that the tweeter wired in this opposite phase sounds better. So, you are correct as you stated + to +. But I wanted to point this out: that in reality the woofer and tweeter are being wired in opposite phase because the back of the woofer cone is the sound producer being mated with the tweeter. I hope this is clear.
Hi Mamboni!
Thanks very much for your feedback - but with the Heils being a dipole I'm not to concerned - heck all I have to do is turn the Heil around 180 degrees! I just wanted to be sure that the resistor and cap were in series - was not sure if you had the resistor in parallel or not.
I'm playing with BudP's EnABL patten at this very moment - getting closer!
Thanks very much for your feedback - but with the Heils being a dipole I'm not to concerned - heck all I have to do is turn the Heil around 180 degrees! I just wanted to be sure that the resistor and cap were in series - was not sure if you had the resistor in parallel or not.
I'm playing with BudP's EnABL patten at this very moment - getting closer!
All involved,
The Heil is not exactly a dipole or a bipolar emitter, but mostly, since air is rarefied on one side while being pressurized on the other side of the mylar sheet, it is technically a Dipole, just as a permanent magnet is a Dipole. See this site for some descriptions and pretty good diagrams of a bit later production than the ESS model.
http://www.soundimage.dk/Different-col/AirMotion.htm
Bud
The Heil is not exactly a dipole or a bipolar emitter, but mostly, since air is rarefied on one side while being pressurized on the other side of the mylar sheet, it is technically a Dipole, just as a permanent magnet is a Dipole. See this site for some descriptions and pretty good diagrams of a bit later production than the ESS model.
http://www.soundimage.dk/Different-col/AirMotion.htm
Bud
Mamboni Variations in D Minor
Having thrown the idea over the transom, here's what I was thinking of in more detail.
1) Visualize 5 big triangles extending all the way from the edge of the cone to the dustcap or the voice coil. They aren't necessarily equilateral triangles, they could have narrower (skinnier) profiles if that works out better. For purposes of illustration, assume the edge-to-dustcap distance of each big triangle is 2.618 inches.
2) There is a medium-size triangle flanking each side (left and right) of the big triangles, so we have 5 big triangles and 10 medium-size triangles. The cone-edge-to-inner-point distance is 1.618 inches for the mid-sized triangles.
3) There are lots of little triangles lining the edge of the cone - these fill in the leftover spaces between the 5 sets of larger triangles, and are 1 inch deep.
4) Scale the dimensions as appropriate to the size of the cone, but keep the size ratios in the Golden Section 1 : 1.618 : 2.618, a subset of the Fibonacci Series.
Unlike the constant-size-triangle approach, this is a "variable-geometry" approach that has substantially different cone-termination distances for different parts of the cone, as well as discouraging the dominant side-to-side and 4-way lateral breakup modes.
Having thrown the idea over the transom, here's what I was thinking of in more detail.
1) Visualize 5 big triangles extending all the way from the edge of the cone to the dustcap or the voice coil. They aren't necessarily equilateral triangles, they could have narrower (skinnier) profiles if that works out better. For purposes of illustration, assume the edge-to-dustcap distance of each big triangle is 2.618 inches.
2) There is a medium-size triangle flanking each side (left and right) of the big triangles, so we have 5 big triangles and 10 medium-size triangles. The cone-edge-to-inner-point distance is 1.618 inches for the mid-sized triangles.
3) There are lots of little triangles lining the edge of the cone - these fill in the leftover spaces between the 5 sets of larger triangles, and are 1 inch deep.
4) Scale the dimensions as appropriate to the size of the cone, but keep the size ratios in the Golden Section 1 : 1.618 : 2.618, a subset of the Fibonacci Series.
Unlike the constant-size-triangle approach, this is a "variable-geometry" approach that has substantially different cone-termination distances for different parts of the cone, as well as discouraging the dominant side-to-side and 4-way lateral breakup modes.
note to self - do not go writing stuff at the forum when tired and or in to much of a hurry to check details. 
To those who wish to see a definition of Dr. Heils Air Motion Transformer please see http://en.wikipedia.org/wiki/Air_Motion_Transformer where it is referred to as a dipole tweeter.
The folks at Oskar Heil Speakers refer to it as bi-directional.
For me - I have simplified things down to - it is one sweet sounding tweeter!! AND I'm putting that sucker on top of MY very own set of speakers that use a Walsh type driver (another way cool transducer with very sweet sound) built by myself with loving care and with guidance from some great and kind people such as Mamboni, BudP and Lynn. For a first time DIYer I just can't imagine having such a great time, learning so much so fast, and building what should be a very fine set of speakers.
BTW - cost to date - around $400.00 for the pair! You can't beat that with a stick!!
As for me - I think I might be going bi-polar!
photo's of the BudP's EnABL pattern we are working on for the project. Now I just have to see if I can get some type of applicator into that tiny space near the VC!
The "white" area in the photo represents the stencil base material and the "black" areas will be the pattern voids where BudP's coating materials will be screened onto the speaker cone. Or you can still use the lettering pens that Bud has discussed in other post.
To those who wish to see a definition of Dr. Heils Air Motion Transformer please see http://en.wikipedia.org/wiki/Air_Motion_Transformer where it is referred to as a dipole tweeter.
The folks at Oskar Heil Speakers refer to it as bi-directional.
For me - I have simplified things down to - it is one sweet sounding tweeter!! AND I'm putting that sucker on top of MY very own set of speakers that use a Walsh type driver (another way cool transducer with very sweet sound) built by myself with loving care and with guidance from some great and kind people such as Mamboni, BudP and Lynn. For a first time DIYer I just can't imagine having such a great time, learning so much so fast, and building what should be a very fine set of speakers.
BTW - cost to date - around $400.00 for the pair! You can't beat that with a stick!!
As for me - I think I might be going bi-polar!
photo's of the BudP's EnABL pattern we are working on for the project. Now I just have to see if I can get some type of applicator into that tiny space near the VC!
The "white" area in the photo represents the stencil base material and the "black" areas will be the pattern voids where BudP's coating materials will be screened onto the speaker cone. Or you can still use the lettering pens that Bud has discussed in other post.
Badman,
The Heil drivers actually perform their activity in a kind of swaying motion. All of the pleats open on one side while the pleats on the other side close. The diaphragm actually "sways" away from the pressure wave it is creating, which, to a degree negates both the pressure wave and depresure wave. This acts, ultimately as a sort of mechanical feed back mechanism and does linearize the emitted wave front, across the diaphragm, just as it emits into the air from the final edges of the pleats. Weird to wrap your head around for sure.
Bud
The Heil drivers actually perform their activity in a kind of swaying motion. All of the pleats open on one side while the pleats on the other side close. The diaphragm actually "sways" away from the pressure wave it is creating, which, to a degree negates both the pressure wave and depresure wave. This acts, ultimately as a sort of mechanical feed back mechanism and does linearize the emitted wave front, across the diaphragm, just as it emits into the air from the final edges of the pleats. Weird to wrap your head around for sure.
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.