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In Reply to: RE: Posey's Doubly-Sad Mathematical Model & The Mars Lunar Lander posted by Posy Rorer on July 30, 2007 at 20:38:51
Ah, but I did take your response as humor. That's why I didn't really answer. You were sort of poking fun at me, but that indeed is no biggie in my book. I most definitely was not trying to 'weasel' out of anything as accused, I simply had really nothing productive or funny to add.The 'sad' was in no way directed at you or your comments. Despite our contrasting views as to causality, your passion is duly noted and I, for one, have no doubts that you are sincere in what you write of.
As for your tests, well, I have posted on some things which lead me to such conclusions which I have come to. I will reiterate a few.
I've a several friends who leave IC's and wires coiled in their sound rooms, a la Belt. One listener has had severe issues with RF entering his TT system, audible not only as static type noise but as a bona fide radio station. He accidentally discovered that placing a coiled up IC on top of his preamp eliminated the RFI. The wire was not hooked up to anything, BTW.
In an old ham radio text, we found a recipe for reducing RFI reception: an octopus arrangement of wires, with each leg trimmed preferably to a fraction of the offending frequencies. We've tried this and it works extremely well, once you figure out the wavelengths. However, a simple random arrangement also works fairly well also
I have used ERS, link provided below, for some time now. The specs and description of it are on the websites, but essentially it is a paper sandwich with a carbon fiber web upon which shards of nickel plated CF are sprinkled. The random lengths of the shards serve as minute antennas for RF which are then grounded to the CF mesh. It is a basis for some of the 'Stealth' technology employed by the military. It works well in areas where the 'Rainbow foil' seems to work best.
RFI has been a large stumbling block for digital/video audio since it's inception. I have been using copper foil tape since at least 1990 to shield every single semiconductor in my CD players, with significant increase in sonic quality. My experiments reached Positive Feedback's writer Doug Blackburn and he actually wrote an article about these mods, however, I had asked me to keep my name out of it at the time. A piece of foil on such chips seems to be effective although I do prefer the ERS.
I routinely advice my customers to ground their metal racks and speaker stands. In my case I have a ladder type rack which actually is an excellent simulation of a Yagi antenna. At any rate grounding the rack seems to create a lower noise floor.
In addition I place small magnets on the supports, midway between the ends. As long as the TT is not on the rack, the result is an improvement in dynamics and subtle tonal textures. Here I know that the magnets are restricting the magnetic induction created by the proximity of the power transformers to the ferrous legs of the rack.
Similarly grounding a metal top plate of a speaker stand seems to 'speed' up the sound. It may be subtle at times since the effect is obviously dependent upon the distance from the magnet structure to the top. Additional experimentation with grounding of the metal speaker driver baskets have yielded positive results. In the case of the ubiquitous stamped steel baskets the ferrous material has a much greater effect on the magnetic field generated from the speaker itself than say a cast aluminum or magnesium basket.
Of great interest is the fact that some speakers are now using composite baskets for even greater performance by a lowering of the magnetic induction. I once discussed this with a noted speaker designer who laughed and told me that he was not surprised since he could measure the magnetic field f his 12 inch woofers five feet away. In this case we were discussing the fact that using non magnetic screws to secure the drivers to the cabinet generated noticeably 'better' sound. The use of such screws is also of benefit any where magnetism is present: transformers are a good target. Replacing the steel bolt in a toroidal transformer mount with one of Nylon or even brass creates a significant 'ease' to the sound, greater midrange, and less high frequency anomalies. As for those steel bolts holding the laminations of the standard EI cores together, they are an abomination. I like to switch them out to brass screws, especially if they are output transformers.
About 25 years ago, I had purchased mu metal and was experimenting with it, building shields for transformers and such. Because mu metal sheet requires a re annealing in a pure hydrogen atmosphere after fabrication, I gravitated to foil and simply used multiple layers.
It is fascinating to see what can be accomplished by 'channeling' magnetic fields. Not in any spiritual sense, but channeling in that magnetic fields would rather enter and remain in a ferrous object rather than enter air. A simple toroidal ring placed over (or under) a motor greatly reduces the size of the field of the motor.
Used under a TT motor the effect is immediately noticeable and greatly beneficial. Centered over the spin motor of a CD also yields great audible benefit, and I have tried this on machines from a the infamous RS portable to the the latest $15K Esoteric machines, with positive results.
The use of this on a CD/DVD player is understandable as the laser head is in very close proximity to the motor. In a TT, the motor can be a foot or even further away, and yet the effect is immediately noticeable. Older VPI's and SOTA's have an external cover upon which you can place the toroid while in play. I can hear the sound changing even before I set the toroid down. Placing a magnet on the steel rack is instantly audible too, but in a negative way, because the steel 'channels' the magnetic field to distances far greater than you would think possible and it affects the field of the cartridge. This is measurable, BTW.
While EMI and RFI fields are relatively mundane and have no 'mystery' to them, the true wonder is the sensitivity of the human organism. While large variations do exist, the defining sensitivity of the human body has yet to be set. I have commented about this on several occasions. The sensitivity of some individuals can be quite amazing, and I do NOT claim such sensitivity by any means.
Stu
Edits: 08/01/07 08/01/07Follow Ups:
> > Ah, but I did take your response as humor. < <
Glad to hear. (No really, I'm very glad that I am able to hear. It makes being an audiophile so much more enjoyable...).
> > The 'sad' was in no way directed at you or your comments. < <
Hmmm... would I have still found it as funny as I did, knowing that? Probably.
> > I've a several friends who leave IC's and wires coiled in their sound rooms, a la Belt. < <
Not sure what you mean by "a la Belt". Don't recall anyone advising this, and I doubt you're talking about reef knots. Perhaps because Belt was a radio engineer in the RAF, he -wants- people to listen to radio stations?
> > One listener has had severe issues with RF entering his TT system, audible not only as static type noise but as a bona fide radio station. He accidentally discovered that placing a coiled up IC on top of his preamp eliminated the RFI. The wire was not hooked up to anything, BTW. < <
I thought it was pretty well known that coiled wires are a likely culprit of RFI, which is why its always advised to keep your wires straight as possible.
> > I have used ERS, link provided below, for some time now. The specs and description of it are on the websites, but essentially it is a paper sandwich with a carbon fiber web upon which shards of nickel plated CF are sprinkled. The random lengths of the shards serve as minute antennas for RF which are then grounded to the CF mesh. It is a basis for some of the 'Stealth' technology employed by the military. It works well in areas where the 'Rainbow foil' seems to work best. < <
So that seems to be a key reason why you feel the Silver Rainbow Foil works by EMI/RFI. You're assuming the ERS product works solely with EMI, because that's what the technology indicates. Perhaps it does. But, have you ever considered the ERS papers may have an effect under Beltism, and this is the reason why the SR foil works well in the same places? The key to sorting the puzzle out is easy: try the SR foil in areas where the ERS papers don't work, but where the SR foil is effective. A mirror or a dead battery in another room, might be one place to start.
> > RFI has been a large stumbling block for digital/video audio since it's inception. I have been using copper foil tape since at least 1990 to shield every single semiconductor in my CD players, with significant increase in sonic quality. My experiments reached Positive Feedback's writer Doug Blackburn and he actually wrote an article about these mods, however, I had asked me to keep my name out of it at the time. A piece of foil on such chips seems to be effective although I do prefer the ERS. < <
It was probably around 1990 when I acquired thin strips of copper to shield the clock crystal and such in my D/A converter. Still have it, but it's one of many such ideas I never got around to testing. I think I tried foil on chips in CD players and such, and didn't succeed at getting good results from those locations (I can't quite remember if it was morphic messages or both, though). I see no reason why copper foil tape wouldn't have a "Beltist" type effect as well (and by that, I don't mean it will improve sound, necessarily). Again, only way I know to test that is to use it on something or somewhere the RFI theory wouldn't hold water. A glass of water, perhaps? ;-)
> > I routinely advice my customers to ground their metal racks and speaker stands. In my case I have a ladder type rack which actually is an excellent simulation of a Yagi antenna. At any rate grounding the rack seems to create a lower noise floor. < <
Again, that reminds me of something I used to do, which is ground the components to the metal rack (just taping a wire from a screw on the back plate to the leg of the rack). At the time I felt it improved things, but the last time I tested that, I had a bit of a change of mind. It screwed something up, can't remember what.
> > In addition I place small magnets on the supports, midway between the ends. As long as the TT is not on the rack, the result is an improvement in dynamics and subtle tonal textures. Here I know that the magnets are restricting the magnetic induction created by the proximity of the power transformers to the ferrous legs of the rack. < <
Magnets on the middle of the legs of the rack?
> > Similarly grounding a metal top plate of a speaker stand seems to 'speed' up the sound. It may be subtle at times since the effect is obviously dependent upon the distance from the magnet structure to the top. Additional experimentation with grounding of the metal speaker driver baskets have yielded positive results. In the case of the ubiquitous stamped steel baskets the ferrous material has a much greater effect on the magnetic field generated from the speaker itself than say a cast aluminum or magnesium basket. < <
I have also done a similar experiment to my friend's speakers. Except I connected the ground wire from the positive terminals of each driver, at the xover, with all wires combined at their end and connected to the amp's ground terminal screw. That and all the silly Belt experiments I did on the speakers really opened the sound up.
> > Of great interest is the fact that some speakers are now using composite baskets for even greater performance by a lowering of the magnetic induction. I once discussed this with a noted speaker designer who laughed and told me that he was not surprised since he could measure the magnetic field f his 12 inch woofers five feet away. In this case we were discussing the fact that using non magnetic screws to secure the drivers to the cabinet generated noticeably 'better' sound. The use of such screws is also of benefit any where magnetism is present: transformers are a good target. Replacing the steel bolt in a toroidal transformer mount with one of Nylon or even brass creates a significant 'ease' to the sound, greater midrange, and less high frequency anomalies. As for those steel bolts holding the laminations of the standard EI cores together, they are an abomination. I like to switch them out to brass screws, especially if they are output transformers. < <
Of course, the theory of the non-magnetic screw follows the same theory of reducing eddy currents, as practiced by Eichmann, Dennis Moorecraft and other pioneering audio engineers.
> > It is fascinating to see what can be accomplished by 'channeling' magnetic fields. < <
Oh yes, I know all about that....
> > The use of this on a CD/DVD player is understandable as the laser head is in very close proximity to the motor. < <
For similar reasons, when I mod a CD player, first thing I do is try to take the transformer as far out of the player as I can. That alone can raise rez.
"silence tells me secretly, everything..."
Clark has offered no mathematical model, apart from one in The Wood Effect concerning polarity (hitherto unmentioned), and there were no landers on any moon of Mars.
clark
sidestepping, sidestepping... The phrase I used was "Mars lander". Are you saying that you worked on a unsuccessful Mars Lunar lander?
8^)
Stu
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