Hi Bud
Any idea on how the pattern was applied and what material was used? Conformal coating should not be a big problem but gluing on all of those little squares is really going to take some time!!
How in the world did they do it?
Could not find any other development of the concept - did / has anyone employed the design?
Interesting idea (the pattern) - but I think that mamboni has allowed for this with his design of the felt pads applied to the cone material - but he is the one to pose an answer to that question. His design looks doable in the DIY sort of way - so I'm headed that way 1st.
But the science looks very interesting! I can feel my mental gears turning - but then there is a lot of rust there!
Any idea on how the pattern was applied and what material was used? Conformal coating should not be a big problem but gluing on all of those little squares is really going to take some time!!
How in the world did they do it?
Could not find any other development of the concept - did / has anyone employed the design?
Interesting idea (the pattern) - but I think that mamboni has allowed for this with his design of the felt pads applied to the cone material - but he is the one to pose an answer to that question. His design looks doable in the DIY sort of way - so I'm headed that way 1st.
But the science looks very interesting! I can feel my mental gears turning - but then there is a lot of rust there!
Hi Bud
Reading your bio I see that we share magnetics in common - but thread isn't about those sort of things. Perhaps I will PM you about a couple of thoughts there. I was thinking about baffles and the use of some paint mixed with fine sand silk screened on with a finish similar to fine sand paper. Silkscreen might also be a method with which to apply your pattern onto a speaker or other surface. I can feel the old mental rust beginning to break free. Retirement - I love the freedom - but it's a bit of a drag to not have all of my technical toys around to play with.
Reading your bio I see that we share magnetics in common - but thread isn't about those sort of things. Perhaps I will PM you about a couple of thoughts there. I was thinking about baffles and the use of some paint mixed with fine sand silk screened on with a finish similar to fine sand paper. Silkscreen might also be a method with which to apply your pattern onto a speaker or other surface. I can feel the old mental rust beginning to break free. Retirement - I love the freedom - but it's a bit of a drag to not have all of my technical toys around to play with.
Thomas and Mamboni,
Please do email me with thoughts we can share.
Thomas, I have literally cracked the code on E/I transformers. I can build a push pull output that does not exhibit hysteresis induced remanence, no zero crossing distortion nor loss of micro dynamic coherence. This has allowed me to explore coil construction formats and dielectric barriers with an eye to matching core material B field permitivity to coil E field / D field permitivity. First results are "voiced" guitar outputs. But now I have really hijacked the thread and apologize to all.
Bud
Please do email me with thoughts we can share.
Thomas, I have literally cracked the code on E/I transformers. I can build a push pull output that does not exhibit hysteresis induced remanence, no zero crossing distortion nor loss of micro dynamic coherence. This has allowed me to explore coil construction formats and dielectric barriers with an eye to matching core material B field permitivity to coil E field / D field permitivity. First results are "voiced" guitar outputs. But now I have really hijacked the thread and apologize to all.
Bud
Hi Bud & Mamboni
I'm thinking: 1) design pattern for 10" cone (for use in this project using mamboni's existing speaker development). Designs or patterns could be developed for other cones as required. 2) print pattern on thin paper using large format printer. You could use a regular printer but large cones would require printing on more than one sheet of paper - or being broken into segments if printed on a single sheet of paper. Those segments would need to be joined and aligned. (Well maybe not - if you only did a section of cone at a time.) 3) remove paper material where printed leaving a stencil pattern in the paper. (Where is my 10KW laser CNC when I really need it!)
4) apply a "tacky" type of spray adhesive to the back of the paper. 3M makes one that I have used to tack up plastic sheeting when spray painting my rooms during remodeling - available at hardware stores. If applied to the paper stencil - not the speaker cone - it should leave little if any residue. 5) apply stencil to speaker cone. 6) mask off areas not to be painted 7) air brush on chosen material (paint, speaker dope, etc.) 7) remove stencil. 8) hook that bad boy up and let it GO - GO - GO!! 
BTW - Bud - Got anything that will do 8 T's for 100ms at 5cps and not require cryo cooling?
I'm thinking: 1) design pattern for 10" cone (for use in this project using mamboni's existing speaker development). Designs or patterns could be developed for other cones as required. 2) print pattern on thin paper using large format printer. You could use a regular printer but large cones would require printing on more than one sheet of paper - or being broken into segments if printed on a single sheet of paper. Those segments would need to be joined and aligned. (Well maybe not - if you only did a section of cone at a time.) 3) remove paper material where printed leaving a stencil pattern in the paper. (Where is my 10KW laser CNC when I really need it!)
4) apply a "tacky" type of spray adhesive to the back of the paper. 3M makes one that I have used to tack up plastic sheeting when spray painting my rooms during remodeling - available at hardware stores. If applied to the paper stencil - not the speaker cone - it should leave little if any residue. 5) apply stencil to speaker cone. 6) mask off areas not to be painted 7) air brush on chosen material (paint, speaker dope, etc.) 7) remove stencil. 8) hook that bad boy up and let it GO - GO - GO!! BTW - Bud - Got anything that will do 8 T's for 100ms at 5cps and not require cryo cooling?
Hi Bud
Hemp paper or cardboard (thin) is great stuff - very though and friendly to the environment. I checked ebay and about the closest I could get was hemp rolling paper - and if we start using that stuff it'll take like 5 or 6 years to get things finished - if we remembered what we started doing in the 1st place. I think the combo of felt and hemp would be a natural - I was checking into Gore-Tex but it looks to be hard to get unless I want to destroy a $160.00 jacket from REI. But if you think that felt has some fibers in it then the fiber count in Gore-Tex will blow you away. But this approach gets us into the area of speaker cone replacement - which while doable can be tricky. Plus we would need to fabricate the cones. That could be done but would present problems to others that follow and want to duplicate this project. Might be tempted to do a prototype for personal use tho
Visited Seattle on my trips to Boeing - loved it - loved the seafood. Have some buds in VC/BC. So what's the latest odds on Mt. R blowing it's lid? My buddies would always throw things at me when I asked them that one
Hemp paper or cardboard (thin) is great stuff - very though and friendly to the environment. I checked ebay and about the closest I could get was hemp rolling paper - and if we start using that stuff it'll take like 5 or 6 years to get things finished - if we remembered what we started doing in the 1st place. I think the combo of felt and hemp would be a natural - I was checking into Gore-Tex but it looks to be hard to get unless I want to destroy a $160.00 jacket from REI. But if you think that felt has some fibers in it then the fiber count in Gore-Tex will blow you away. But this approach gets us into the area of speaker cone replacement - which while doable can be tricky. Plus we would need to fabricate the cones. That could be done but would present problems to others that follow and want to duplicate this project. Might be tempted to do a prototype for personal use tho
Visited Seattle on my trips to Boeing - loved it - loved the seafood. Have some buds in VC/BC. So what's the latest odds on Mt. R blowing it's lid? My buddies would always throw things at me when I asked them that one
Hey BudP:
These guys are up in your neck of the woods and do laser and dye cutting. http://www.mag-knight.com/diecutting/
I don't have your pattern so really can't talk to them about a bid - plus - it's your pattern and your patent so for me to discuss anything without your permission would be way out of line
But I'm thinking that if enough interest in your EnABLE pattern is generated it might be worth considering having a pattern cut on to a vellum mask that could be applied to the speaker cone and removed once the pattern is applied with chosen material - say adhesive and powered felt - or paint, ink, speaker dope - whatever. These guys might be able to cut the lam's for your xformers too.
Just a thought
BTW - your xformer ideas could be a big hit with the tube and power supply forums - ya might want to check 'em out.
These guys are up in your neck of the woods and do laser and dye cutting. http://www.mag-knight.com/diecutting/
I don't have your pattern so really can't talk to them about a bid - plus - it's your pattern and your patent so for me to discuss anything without your permission would be way out of line
But I'm thinking that if enough interest in your EnABLE pattern is generated it might be worth considering having a pattern cut on to a vellum mask that could be applied to the speaker cone and removed once the pattern is applied with chosen material - say adhesive and powered felt - or paint, ink, speaker dope - whatever. These guys might be able to cut the lam's for your xformers too.
Just a thought
BTW - your xformer ideas could be a big hit with the tube and power supply forums - ya might want to check 'em out.
Yum 
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.
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.
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.
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?
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