I can't resist. Too much idle time. The equations of Newton and Coulomb are quite adequate for considering the situation at hand. You used their constants yourself as a basis for your statement about the relative magnitude of the two forces. No need for a unified theory here, which anyway does not exist. The reasons that your blanket statement about the relative strengths of gravity and electrostatic charge does not hold water are at least two-fold: (1) The units of the gravitational constant and Coulomb's constant are different. You cannot just assume that a numerical ratio between two different quantities is meaningful without considering the units (apples and oranges), and (2) in one case the objects are considered only for their mass (Newton) and in the other case the objects are considered only for their charge (Coulomb). I would say yes, in some cases the ES force can be greater than the gravitational force. In other cases, no, gravity dominates. It depends upon mass vs charge. One other difference between gravity and the ES force is that gravity is generally a force of attraction between two objects, whereas the ES force can be a force of repulsion, when the charges are alike in polarity, or attraction, when the charges are opposite in polarity. (Yes, I know about the question of whether the reason the universe is expanding means there is a repulsive form of gravity caused by dark matter, etc. But that is not an earthly problem.)
Some thoughts on dust covers
Over the course of time there have been many discussions concerning the subject of dust covers. They tend to revolve around the central question: Should the dust cover be down or up while playing records? Some of these discussions have been nasty, consequently I have refrained from participation. It is hoped that I can provide some common sense that was given to me by someone of unquestioned authority many years ago. During college and after, from 1970 to ~1980 I worked in HiFi retail, selling high end lines of audio equipment. One of these lines was Thorens. Sometime around 1977 or 1978, if memory serves, Thorens introduced their new TD126, as a top of the line TT with their own arm and I sold the first one at our store to very good customer. He came back very unhappy after the first night of frustration with it. The problem was that with the dust cover closed some of his favorite records were hitting tangentally on the very back were the platter came closest to the dust cover when it was in the closed position. I called the manufacturer's rep and he set up a three cornered phone call with himself, the Chief Engineer of Thorens at the time, and me. I don't recall the man's name, but it doesn't matter, it is what he said that matters, then and now. The Chief Engineer explained that the problem was caused because the hole in the offending records was slightly off center so there was an eccentricity as such a record rotates about the spindle. The solution was simplicity itself, the dust cover should be removed always when playing records. That the intent of the cover is to protect the turntable when not in use. I pointed out that we lived in a semi-arrid environment (San Diego, CA) which is dusty to which he replied that if the environment was too dusty for records it should also be considered unhealthy for people to be breathing the air. He recommended are filtration, not dust covers to address environmental concerns. The rep asked about air bourne feedback from speakers and the Thorens guy laughed and said that if that was a problem in a given system, relying of the dust cover was a very flimsy and ineffective solution and that proper measures should be instituted to provide meaningful distance and isolation to ameliorate the problem. So the often offered extremes: a) Always play your records with the dust cover down, or b) put the dust cover away in it's box and never use it, should both be recognized for what they are are - not solutions at all. First principles: Identify the problem(s), seek solutions and alternatives, prioritize.
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My-O-My ! I never expected to kick up so much "dust" with my re-telling of the story of when my audio dealer dusted his turntable dust cover and created enough magnetism to alter the stylus force ! Perhaps we can end it all simply by turning our attention to another interesting thing I noticed on my 1920's Victor "Credenza". On the lowest portion of the rather sizeable and heavy lid is a decal that states, "Close Lid Whilst Playing". Since it was effectively the turntable dust cover, I hope to stay within the confines of the original post. There definitely is a difference in the quality of sound when following the directions though I've never decided whether it was a diminution of the very noticeable stylus "scratch" or a real enhancement of the sound as a result of confining the sound box to a more restrictive acoustic. Victor even encouraged the regimen of closing the lid by providing the lid with two "dashpots" which damp the lid closure enough to prevent any slamming effect. On the Columbia "360" record player from the 1950's, the edges of the lid were lined with felt so that when the lid was closed it definitely created a different acoustic situation in which the cartridge had to function. The Speakers were located on the opposite sides of the unit and one driver was purposely wired "out of phase" to create a diffusive effect. Later models of the "360", though much more modern in the cabinet design, went even more deeply into the idea of encapsulating the cartridge in its own acoustic by integrating a fully sealed plastic container within the player to isolate the cartridge even more fully than the original model. You almost have to pry the lid to open it ! My question is : Were there any modern turntables that had a dust cover/lid that was designed purposely to be closed during the play cycle to take advantage [?] of the difference between an open or closed acoustic surrounding the cartridge ? Some of us have certainly experienced acoustic feedback when positioning a loudspeaker too close to a sensitive turntable that created an acoustic feedback through the cartridge, so the reasoning follows that attention to the acoustic in which a cartridge must function is important. I own both an early and late Columbia "360" machine and there are mono records that sound like fine stereo recordings on these machines ! Amazing !! The outer lids on both the Victrola and the Columbia "360' machines were of wood so they could not be magnetized. Thoughts ? Experiences ? |
I think the easy way out of this impasse and high blood pressure is….
Cover or lid, which ever way you want to play it….. ———————-
1. If the thoughts of dust filling your groove ruins your musical enjoyment, and have a lid…keep the lid down. 2. If you are worried that the sound will be compromised with the lid down or know it will be, as Arnie would say….’Don’t dooo iit! 3. If your hi-fi sounds great to your ears, you are happy with listening to music and you don’t notice a difference up or down….and have a lid, stick it down and save a lot of additional cleaning! 4. If you have a turntable without a lid, content or enjoy sometimes a little dusting fore play each time you want to listen….stick to a turntable without a lid! I think l have about covered it? That’s my Logic
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I'm not qualified to speak on static, but dust I do know about, especially with respect to inhaling it and the allergies it can cause. When you wrote, @lewm ,
I'm afraid you are wrong. The predominant, component of household dust is human skin, though I expect it has been shed rather than shredded. |
@lewm @dogberry According to this it's a "myth" that dust is mostly dead skin https://www.livescience.com/32337-is-house-dust-mostly-dead-skin.html Couldn't read the Canadian dust study w/o a subscription... FWIW |
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