Thomas and Bud:
I'm reading your discssion with great interest. By the way, I am a physician by trade and training and not as proficient as you guys in the technical and engineering aspects. I would most interested in what you guys come up wiht and hope you will post some photos.
Thomas hit on all the key features that determined selection of the 10" Pioneer woofer. The thing is, as you guys have noted, loudspeaker manufacturers experiment with all manner of exotic materials and coatings in an effort to eliminate boundary effects/cone resonance. But, the technique we are using here requires no exotic materials, just a modicum of engineering and design. And in the bargain, one has converted an inexpensive woofer into one that can match or exceed the expensive exotics with the fancy composite cones and proprietary viscoelastic coatings. Now I do not have the setup to do detailed frequency reponse and waterfall plots, and I suspect Bud does; but, based on my hearing the felt-treated woofer sounds amazing clean and delicate, as if all manner of energy storage has been eliminated. But, one would need measurement of a treated woofer to prove this. If this is true, then these post-production mods might have a market, either as ready-use modified woofers or kits for the user to apply the treatment himself. Imagine the advantages: a woofer that is non-resonant and resistant to cone breakup would require no crossover, and would sound superior to almsot any "coventional" woofer. It could be a boon to hobbyists who want to build a phase and time correct loudspeaker and eliminate the crossover.
I'm reading your discssion with great interest. By the way, I am a physician by trade and training and not as proficient as you guys in the technical and engineering aspects. I would most interested in what you guys come up wiht and hope you will post some photos.
Thomas hit on all the key features that determined selection of the 10" Pioneer woofer. The thing is, as you guys have noted, loudspeaker manufacturers experiment with all manner of exotic materials and coatings in an effort to eliminate boundary effects/cone resonance. But, the technique we are using here requires no exotic materials, just a modicum of engineering and design. And in the bargain, one has converted an inexpensive woofer into one that can match or exceed the expensive exotics with the fancy composite cones and proprietary viscoelastic coatings. Now I do not have the setup to do detailed frequency reponse and waterfall plots, and I suspect Bud does; but, based on my hearing the felt-treated woofer sounds amazing clean and delicate, as if all manner of energy storage has been eliminated. But, one would need measurement of a treated woofer to prove this. If this is true, then these post-production mods might have a market, either as ready-use modified woofers or kits for the user to apply the treatment himself. Imagine the advantages: a woofer that is non-resonant and resistant to cone breakup would require no crossover, and would sound superior to almsot any "coventional" woofer. It could be a boon to hobbyists who want to build a phase and time correct loudspeaker and eliminate the crossover.
Very interesting thread!
BudP can you be more specific as what kind of "conformal coating material " is exactly. What are your suggestions?
Mamboni: How the sound of the modified driver (Mamboni's driver) can compare with the sound of the actual Walsh driver (the latest incarnation).
Anyway, without any doubts, I will do some experiment with Mamboni approach in the coming weeks. It will be very fun to explore this kind of concept at this price point.
BudP can you be more specific as what kind of "conformal coating material " is exactly. What are your suggestions?
Mamboni: How the sound of the modified driver (Mamboni's driver) can compare with the sound of the actual Walsh driver (the latest incarnation).
Anyway, without any doubts, I will do some experiment with Mamboni approach in the coming weeks. It will be very fun to explore this kind of concept at this price point.
Utopix said:
The mamboni driver (if you don't mind a bit of self-promotion...LOL) sounds exactly like my treasured Walsh 5 Series 3 loudspeakers, except for two differences:
1. The Walsh 5's produce world class bass flat to 20 hz - this is basic physics at work: bigger cabinet, bigger driver, bigger magnet and some darn ingenious design by Ohm. The mamboni's are flat to 49 hz but as they are acoustic suspension, will produce quite servicable, tight and tuneful bass to about 40 hz.
2. the mamboni driver has a larger soundstage than the Walsh 5, because the latter has sound-absorbing pad behind the drivers to limit rear radiation and allow for easier room placement near boundaries.
The kicker is, one can get about 90% of the performance of the Walsh 5 Series 3, a $5000+ loudspeaker, for $200 in parts and a couple of days labor needed to build the project loudspeaker. Enough said.
Utopix,
Ummm.... acrylic floor wax.... industrial strength. I buy mine from Micro Scale Products, called Micro Gloss. The real deal is that it needs to exhibit transverse wave energy transfer at speeds faster than that of sound through air. Most varnishes and lacquers will not do this and you can clearly hear the difference, but I have never found a way to measure it.
The paint I use to letter the blocks onto a driver surface is made by Poly Scale corp. Flat Finish #404106. Both of these materials will be in any decent hobby shop that sells plastic models and some HO scale train items.
Mamboni,
I am delighted to see the interest you have stirred up. Have you thought about using your process on more conventional speakers? Still placed on the non free air emitting surface, I suspect that a considerable improvement in midrange driver clarity might result. We may be stuck with just the EnABL process for dome, cone and linnaeum style tweeters... though I have seen the odd Walsh based tweeter show up. Not a drawback. Certainly a conventional speaker setup, with your pattern on the back of woofer and cone midrange, my pattern on the front to lightly correct whats left over, and an EnABLE'd tweeter, will rival the Ohms for clarity, depth of field and sheer musical beauty. And that is saying something!
While it has taken some number of years to accomplish I have a conventional system that will easily outperform my original treated Ohm F's in all of the categories you would care to list, so I am sure your idea can be so applied and between us we may just get as close to perfection as humans in the real world can accomplish.
Bud
I am still very intrigued to try both processes together, I do sense a possibility of synergy.
Ummm.... acrylic floor wax.... industrial strength. I buy mine from Micro Scale Products, called Micro Gloss. The real deal is that it needs to exhibit transverse wave energy transfer at speeds faster than that of sound through air. Most varnishes and lacquers will not do this and you can clearly hear the difference, but I have never found a way to measure it.
The paint I use to letter the blocks onto a driver surface is made by Poly Scale corp. Flat Finish #404106. Both of these materials will be in any decent hobby shop that sells plastic models and some HO scale train items.
Mamboni,
I am delighted to see the interest you have stirred up. Have you thought about using your process on more conventional speakers? Still placed on the non free air emitting surface, I suspect that a considerable improvement in midrange driver clarity might result. We may be stuck with just the EnABL process for dome, cone and linnaeum style tweeters... though I have seen the odd Walsh based tweeter show up. Not a drawback. Certainly a conventional speaker setup, with your pattern on the back of woofer and cone midrange, my pattern on the front to lightly correct whats left over, and an EnABLE'd tweeter, will rival the Ohms for clarity, depth of field and sheer musical beauty. And that is saying something!
While it has taken some number of years to accomplish I have a conventional system that will easily outperform my original treated Ohm F's in all of the categories you would care to list, so I am sure your idea can be so applied and between us we may just get as close to perfection as humans in the real world can accomplish.
Bud
I am still very intrigued to try both processes together, I do sense a possibility of synergy.
Mamboni, BudP
Thank you both for your answers.
Mamboni: I'm sure you are aware that Ohm Acoustic just recently began to sell their "Walsh" driver in a new kind of configuration. The HT configuration. Sub+Sat. Their driver is in a smaller box that can be put on top of a Sub(crossover at 80 hz). Now, I'm sure that the sound of this setup is as good as their normal setup for audio only. So for me, the bass output of your approach is not a problem, and in fact I think that putting a separate sub for the 20-80 hz zone is a very good solution. Why push the enveloppe of your modified driver too low?. Have you tried to put a sub with your driver (high pass filter on your driver at 80 hz) to see how it will behave?
Thank you both for your answers.
Mamboni: I'm sure you are aware that Ohm Acoustic just recently began to sell their "Walsh" driver in a new kind of configuration. The HT configuration. Sub+Sat. Their driver is in a smaller box that can be put on top of a Sub(crossover at 80 hz). Now, I'm sure that the sound of this setup is as good as their normal setup for audio only. So for me, the bass output of your approach is not a problem, and in fact I think that putting a separate sub for the 20-80 hz zone is a very good solution. Why push the enveloppe of your modified driver too low?. Have you tried to put a sub with your driver (high pass filter on your driver at 80 hz) to see how it will behave?
How nice! I've been wanting a small and inexpensive omnidirectional system to experiment with. To that end, I'm thinking of implementing Mamboni's process, as it seems simpler. I'm also considering using smaller drivers than the 10in pioneer.
I have some questions, Mamboni. I read the whole thread, but it's starting to get long so I beg your forgiveness if I have read past some vital bit. I wonder, how have you chosen the height of your felt triangles? Is the ratio of triangle h to cone radius constant? Does the number of triangles matter? I saw that you preferred paper cones for this mod - do you have any other recommendations for alternate driver choices? Have you tried this on other drivers?
Verrry innnnteresting.....
I have some questions, Mamboni. I read the whole thread, but it's starting to get long so I beg your forgiveness if I have read past some vital bit. I wonder, how have you chosen the height of your felt triangles? Is the ratio of triangle h to cone radius constant? Does the number of triangles matter? I saw that you preferred paper cones for this mod - do you have any other recommendations for alternate driver choices? Have you tried this on other drivers?
Verrry innnnteresting.....
BudP said:
It would be informative to perform some woofer waterfall response plots before and after the treatments: EnABL and felt damping. This should clearly show effectively resonances are being eliminated.
Can you elaborate further on how the EnABL pattern is calculated for a given woofer? How critical is the size and placement of the treated squares?
Utopix said:
Well, I am presently running the "mamboni" loudspeakers full range, but with a stereo pair of Kinergenics subwoofers (two 10" drivers per side - acoustic suspension - -3dB at 17 hz) with low pass crossing over at 100 hz. The blend is perfect and the sound rivals my Walsh 5s.
Yes, excellent results can be obtained using small drivers on small cabinets operating as Walshs, with separate sub for the bass. This is the approach used by Ohm in their relatively new line of "microWalshs." These are getting rave reviews on the internet audioreview site. It would be a snap to build a set of four using a good quality 5 inch woofer (Silverflute comes to mind) wiht the felt damping and EnABL applied to the cone for a truly transparent and pristine clean sound. The cabinets could be tall and narrow with a small non-obtrusive footprint, and a volume circa 1 cu ft. A high crossover point of 10-12 khz should be easily employed, so that one could employ a small ribbon or 3/4" dome tweeter and still have outstanding power handling. Also, the dome tweeter could be a minimum baffle design on a swivel, so the front speakers could employ forward firing tweeters, and the rear speaker tweeters could be easily pointed up at the ceiling and act as surround speakers. A crossover to a subwoofer at 80-100 hz shoudl be very easy to accomplish. This is what I would build if I wanted a sound system that can be both an excellent stereo reproduction platform and home theatre.
Getting you some tools
Mamboni,
I have to reinstall Auto Cad 14, after that herculean task is accomplished I can plot a set of patterns based upon large end diameter, small end diameter, height of cone and thickness. This plot will be on a flat piece of paper that you can then roll up into a cone.
Many years ago I wrote a lisp program for taking this data and creating this flat drawing , with all blocks, and proper spacing from edges included.
If there is interest I will make the lisp program, which runs in Auto Cad 14 and possibly later versions, available for free. With that and a Corel file I can provide you can make cone templates that will show you where to put the blocks and scaleable Corel circular templates, to guide your placement of blocks for a given pattern. There are always two patterns for a cone surface and the smaller pattern can be merged with one that will be applied to a center dome for a three row pattern with the first and third rows on the dome and cone respectively and the middle row in the joint between.
This process will take a day or so to get up and running again and I will then ask you for dimensions for a cone that interests you, though I may not be able to plot the file, as I no longer have a large format plotter. I am sure you can find someone to help you with this. The Corel file does require Corel 6 or newer to allow you to open and scale the circles of blocks to a useful size, but, again this should not be hard to obtain as most printing companies can print from both Corel files and Auto Cad DWG files.
Bud
Mamboni,
I have to reinstall Auto Cad 14, after that herculean task is accomplished I can plot a set of patterns based upon large end diameter, small end diameter, height of cone and thickness. This plot will be on a flat piece of paper that you can then roll up into a cone.
Many years ago I wrote a lisp program for taking this data and creating this flat drawing , with all blocks, and proper spacing from edges included.
If there is interest I will make the lisp program, which runs in Auto Cad 14 and possibly later versions, available for free. With that and a Corel file I can provide you can make cone templates that will show you where to put the blocks and scaleable Corel circular templates, to guide your placement of blocks for a given pattern. There are always two patterns for a cone surface and the smaller pattern can be merged with one that will be applied to a center dome for a three row pattern with the first and third rows on the dome and cone respectively and the middle row in the joint between.
This process will take a day or so to get up and running again and I will then ask you for dimensions for a cone that interests you, though I may not be able to plot the file, as I no longer have a large format plotter. I am sure you can find someone to help you with this. The Corel file does require Corel 6 or newer to allow you to open and scale the circles of blocks to a useful size, but, again this should not be hard to obtain as most printing companies can print from both Corel files and Auto Cad DWG files.
Bud
AdamThorne said:
The felt triangle dimensions were arrived at by intuition, an educated guess. The great weakness of a standard woofer is the radial symmetry of the cone, which is a setup for boundary-induced resonance. The felt adds increased acoustic resistance to the cone, and causes it to appear virtually longer to the voice coil's impulse action. The cone element terminated with felt appears as a longer transmission line. The boundary is extended to near infinity. By using triangular felt pads, the goal is to create a cone membrane of undefined or continuously variable lengths, to discourage resonances. One could have applied an increasingly heavy damping to the cone in a continuous graded manner (i.e. spray-on felt?) and achieved the same effect. Enough felt triangles are added so that at the cone-surround junction, almost the entire circumference is felted. For all I know, shorter triangles or fewer triangle would work as well. I suspect the design is very forgiving and there is surplus damping presently. The triangles are an approximation of a continuously increasing acoustic resistance - the result is a substantially non-resonant (i.e. linear) transmission line (cone diaphragm).
I chose the paper woofer because paper cones offer the best price-performance and are underdamped, which is desirable. The Pioneer 10" woofer is a terrible driver in the midrange - just loaded with resonances well into the 3-6 khz range. This is just what I needed - a low mass bending wave. I anticipated that the added felt dampling would tame these resonances and result in a bending wave transducer with exceptional high frequency extension (it is important that the voice coil be low mass and low inductance as well). It worked like a charm! This particlaur woofer has a very large and powerful ceramic magnet for the price, good for high efficiency and low Q.
There is no doubt in my mind that the felt approach will work equally well with woofers using more exotic materials, like metal, kevlar and carbon fiber. I have a particular 8" woofer in mind for my next project, an Usher driver that is reasonably priced, uses a very stiff carbon fiber-kevlar cone, a large magnet, a low inductance low mass high Xmax coil and a low acousitc profile cast frame. The Q, Vas, and Fs are the perfect combination for a vented cabinet with bass down to the mid 30's Hz and this driver should reach up into the 8-10khz range. I am considering a ribbon tweeter.
Utopix - mamboni
Tang makes a nice 5.25 speaker that will go up to 13 Khz http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=264-850
only 88 dbs tho.
BTW mamboni - how "dead" should the sonotube be? I know you said stuff to about 50% but I'm wondering if a bit of treatment on the inside of the tube might improve things. I could coat the inside with some rubberized asphalt and get the wall of the tube really quiet - but is there anything to be gained?
Thinking of a "small" system as well for HT - but I want to finish this one first to learn from. BudP and I are working on a process to apply his EnABL pattern. Still brainstorming - but making progress.
Tang makes a nice 5.25 speaker that will go up to 13 Khz http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=264-850
only 88 dbs tho.
BTW mamboni - how "dead" should the sonotube be? I know you said stuff to about 50% but I'm wondering if a bit of treatment on the inside of the tube might improve things. I could coat the inside with some rubberized asphalt and get the wall of the tube really quiet - but is there anything to be gained?
Thinking of a "small" system as well for HT - but I want to finish this one first to learn from. BudP and I are working on a process to apply his EnABL pattern. Still brainstorming - but making progress.
Mamboni and all,
Here is a sample cone you can cut out and make into a cone, either an innie or an outie. As you can see the block size in a ring set changes with the actual diameter that it must cover. The lisp program that I have performs all of these calculations and draws the resultant conic section as a flat surface. I have converted it ot a jpeg format for your convenience
The specifications need to be for:
The large cone opening diameter, or the diameter just at the lowest edge of the surround where it overlaps the cone.
The small cone opening diameter, or where the center dome actually touches the cone surface.
The material thickness, a guess will do.
The length down the cone surface from the surround lower edge to the top edge of dome attachment, on the cone.
Obviously these dimension call out specs are aimed at the normal face of a cone speaker, but I am sure all of you can see how to use the dimension call outs for the backside or Walsh side of the cone.
Dr. Mamboni, when you have a set of dimensions you want to experiment with, and I would strongly suggest a small diameter cone, like a 6.5", so we can keep the conic lay out sheet on a letter size piece of paper, I can provide another of these, close to correctly sized and the Corel block rings that you would use as a location template, to actually letter the blocks in place on the cone surface.
This is not as complicated as it sounds here. The teenagers I have taught this to take about 30 minutes to completely treat a cone, on both sides, with blocks and conformal coat.
Bud
Here is a sample cone you can cut out and make into a cone, either an innie or an outie. As you can see the block size in a ring set changes with the actual diameter that it must cover. The lisp program that I have performs all of these calculations and draws the resultant conic section as a flat surface. I have converted it ot a jpeg format for your convenience
The specifications need to be for:
The large cone opening diameter, or the diameter just at the lowest edge of the surround where it overlaps the cone.
The small cone opening diameter, or where the center dome actually touches the cone surface.
The material thickness, a guess will do.
The length down the cone surface from the surround lower edge to the top edge of dome attachment, on the cone.
Obviously these dimension call out specs are aimed at the normal face of a cone speaker, but I am sure all of you can see how to use the dimension call outs for the backside or Walsh side of the cone.
Dr. Mamboni, when you have a set of dimensions you want to experiment with, and I would strongly suggest a small diameter cone, like a 6.5", so we can keep the conic lay out sheet on a letter size piece of paper, I can provide another of these, close to correctly sized and the Corel block rings that you would use as a location template, to actually letter the blocks in place on the cone surface.
This is not as complicated as it sounds here. The teenagers I have taught this to take about 30 minutes to completely treat a cone, on both sides, with blocks and conformal coat.
Bud
c2cthomas said:Utopix - mamboni
Tang makes a nice 5.25 speaker that will go up to 13 Khz http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=264-850
only 88 dbs tho.
BTW mamboni - how "dead" should the sonotube be? I know you said stuff to about 50% but I'm wondering if a bit of treatment on the inside of the tube might improve things. I could coat the inside with some rubberized asphalt and get the wall of the tube really quiet - but is there anything to be gained?
Thinking of a "small" system as well for HT - but I want to finish this one first to learn from. BudP and I are working on a process to apply his EnABL pattern. Still brainstorming - but making progress.
I confident that Tangband driver can be adapted to a microwalsh-type loudspeaker. You should be able to get bass down to loe 50's in a ported box of less than 1 cu ft. I have an Xcel spreadsheat that calculates all the ideal box volumes and port dimensions given Vas, Qts, Fs etc.
Cardboard is one of the most acoustically dead materials availble, and a cylinder is intrinsically rigid. Certainly, rubberized asphalt will improve damping and rigidity - I can't say whether it will improve the sound - perhaps slightly. Ohm sounds cyclinders were cardboard tubes lines with lead sheets - nothing kills vibration like lead!
Too bad one cannot obtain more data on that Tangband woofer: personally, I don't like buying one without complete FR plot, and coil inductance included with the TS parameters. By the way, as one used smaller driver, cone resonances generally become less of an issue. Here is a 5" woofer worth considering - excellent performance specs - wool cones are well-behaved, and the price is right:
Silver Flute W14RC25 5-1/2" Wool Cone
http://www.madisound.com/cgi-bin/index.cgi?cart_id=8826466.12203&pid=1074
BudP said:
If I understand correctly, one need only cut out the rectangular sections to create the stencil, yes? I was just ondering, couldn't one substitute a pattern of circles - I happen to own one of those hand-held punch guns, and it would be a snap to use. Otherwise, one must cout the rectangles by free hand using an exacto knife.
So, you are proposing applying the EnABL pattern to the front of the cone, and felt damping to the back of the cone, yes?
Hi Mamboni
I did see the Silver Flute and know that they make very nice speakers - but I couldn't see any HF info about it. Just about anything small like this would work for a small system when combined with a decent HF driver used in accordance with your design. I'm still headed in the direction of your larger design for now - I'm loving it more and more every day. BudP and I have been having great fun discussing surface tension and wave theory as to being able to cause an interference boundary and I think we are nearly ready for 1st generation prototypes. Of course before we finished with the 1st generation designs I began fooling around with some even more advanced pattern theory for the blocks that may serve to make an even better device. I'm feeling BENT!!
I did see the Silver Flute and know that they make very nice speakers - but I couldn't see any HF info about it. Just about anything small like this would work for a small system when combined with a decent HF driver used in accordance with your design. I'm still headed in the direction of your larger design for now - I'm loving it more and more every day. BudP and I have been having great fun discussing surface tension and wave theory as to being able to cause an interference boundary and I think we are nearly ready for 1st generation prototypes. Of course before we finished with the 1st generation designs I began fooling around with some even more advanced pattern theory for the blocks that may serve to make an even better device. I'm feeling BENT!!
Hi Mamboni.
I did not really intend that one as a stencil, cutting all of those squares would take at least three times longer than just drawing, or "lettering" the blocks in place using the traditional method with a calligraphy pen and a circular chart of block placement, based upon the diameter and size found in the type of "stencil" you have now seen.
Thomas and I are converging on a method for stencil making with either etched block pattern circular strips, that wrap half way around the cone for one set of block rows, with a 3M tack adhesive on the back and a sponge to dab the openings with, or a laser cut vellum stencil, with the same tack adhesive and 1/2 cone circumference strip scheme.
I am proposing just what you portray, EnABL on the outside and Mamboni on the inside, just how and where you place it now. I do not think that a heavy application of EnABL control will be needed at all. You will almost certainly see benefits in extended high frequency range, roll off smoothness and quite possibly a 3 dB increase in overall efficiency, though that is never a given, unless you do not want it to happen.
I have attached a sample flat block guide that would be used to guide placement of the blocks with a lettering pen.
I did not really intend that one as a stencil, cutting all of those squares would take at least three times longer than just drawing, or "lettering" the blocks in place using the traditional method with a calligraphy pen and a circular chart of block placement, based upon the diameter and size found in the type of "stencil" you have now seen.
Thomas and I are converging on a method for stencil making with either etched block pattern circular strips, that wrap half way around the cone for one set of block rows, with a 3M tack adhesive on the back and a sponge to dab the openings with, or a laser cut vellum stencil, with the same tack adhesive and 1/2 cone circumference strip scheme.
I am proposing just what you portray, EnABL on the outside and Mamboni on the inside, just how and where you place it now. I do not think that a heavy application of EnABL control will be needed at all. You will almost certainly see benefits in extended high frequency range, roll off smoothness and quite possibly a 3 dB increase in overall efficiency, though that is never a given, unless you do not want it to happen.
I have attached a sample flat block guide that would be used to guide placement of the blocks with a lettering pen.
BudP
May I make a suggestion for the stencil for large diameter woofer(like the 10" woofer that mamboni already made). You can print on a single sheet of paper only a small portion of the stencil, not the complete cone. (See attached picture).
As you can see, we this new stencil we only have to paint the blocks from 1 to 10(big blocks and small blocks) on the woofer cone, after that we just move the stencil to the right and align the 1-2 holes of the stencil on top of the already paint block number 9-10 (for alignement). And we move on until the entire woofer cone is done. Unless the block alignement must be precise within a 1/100 th on an inch, I think that this method is valid.
With that in mind, it is easy to imagine that you can generate (with your program) on a single sheet of paper many different template for different woofer.
Just a thought!
May I make a suggestion for the stencil for large diameter woofer(like the 10" woofer that mamboni already made). You can print on a single sheet of paper only a small portion of the stencil, not the complete cone. (See attached picture).
As you can see, we this new stencil we only have to paint the blocks from 1 to 10(big blocks and small blocks) on the woofer cone, after that we just move the stencil to the right and align the 1-2 holes of the stencil on top of the already paint block number 9-10 (for alignement). And we move on until the entire woofer cone is done. Unless the block alignement must be precise within a 1/100 th on an inch, I think that this method is valid.
With that in mind, it is easy to imagine that you can generate (with your program) on a single sheet of paper many different template for different woofer.
Just a thought!
Utopix,
Quite an excellent thought. Are you ready to give it a try?
Using your method we can make a flat pattern that sits just below where you will letter the pattern. A good convention is that the blocks closest to the cone describe the blocks right next to them and then you use the lower blocks already on the cone to describe the length of the whole upper block set and just get as close as you can for the correct space between the upper blocks. I usually do two lower blocks and then the upper between them so I am able to clearly see the pattern I am creating. This will be good enough, I assure you.
We might still want to have the upper, or smaller diameter pattern be a full circumference, with perhaps a single slit so you can get it on to the cone and then tape it back together and let it settle.
Just as with Mamboni's treatment there is a lot of forgiveness for small errors.
If you have access to a copy of Corel 6 or newer, and I am certain it is available on eBay, I can post the latest flat twin ring file and you can size it to fit your needs exactly and print out a full sheet with as much of the diameter of the cone you want to work with, or as much as the letter size paper will hold. I do believe you have found the key, thank you.
Bud
Quite an excellent thought. Are you ready to give it a try?
Using your method we can make a flat pattern that sits just below where you will letter the pattern. A good convention is that the blocks closest to the cone describe the blocks right next to them and then you use the lower blocks already on the cone to describe the length of the whole upper block set and just get as close as you can for the correct space between the upper blocks. I usually do two lower blocks and then the upper between them so I am able to clearly see the pattern I am creating. This will be good enough, I assure you.
We might still want to have the upper, or smaller diameter pattern be a full circumference, with perhaps a single slit so you can get it on to the cone and then tape it back together and let it settle.
Just as with Mamboni's treatment there is a lot of forgiveness for small errors.
If you have access to a copy of Corel 6 or newer, and I am certain it is available on eBay, I can post the latest flat twin ring file and you can size it to fit your needs exactly and print out a full sheet with as much of the diameter of the cone you want to work with, or as much as the letter size paper will hold. I do believe you have found the key, thank you.
Bud
Has anyone thought of looking at the ripple pattern produced by the Enable array when used at the far end of a shallow water ripple tank? Remember these simple analog/mechanical devices used before computers?
Although the claim of performance is not in question here at all I think it would be interesting to see the way it works. While at it a triangular edge could be tested as well.
Although the claim of performance is not in question here at all I think it would be interesting to see the way it works. While at it a triangular edge could be tested as well.
Hi Bob,
The good old ripple tank is what BudP was using when he originally thought up his EnABL pattern back in 1973 - but he can tell you that story. It is also what I mentally used when discussing interference patterns and wave theory with BudP in attempting to design an ideal pattern and shapes of the "blocks" used in such a pattern. I won't go into that here because 1) it would take to long 2) put me at risk of showing that I know just enough to be dangerous.
Here is a sample of what I have been playing around with. Wish I had some FEM software and a supercomputer.
Cheers - Thomas
The good old ripple tank is what BudP was using when he originally thought up his EnABL pattern back in 1973 - but he can tell you that story. It is also what I mentally used when discussing interference patterns and wave theory with BudP in attempting to design an ideal pattern and shapes of the "blocks" used in such a pattern. I won't go into that here because 1) it would take to long 2) put me at risk of showing that I know just enough to be dangerous.
Here is a sample of what I have been playing around with. Wish I had some FEM software and a supercomputer.
Cheers - Thomas