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Re: You might think I'm crazy, but I'm not...
#77233 01/21/05 11:18 PM
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My parents and I worked our butts off so I could spend 4 years of my life learning how those electrons gallop through various materials and do different things. There's a veritable playground of galloping electrons in there... Why not share the wealth? Watching them is much momre fun than watching Lemmings on your computer.

The relationship between magnets and AC current has always fascinated me. There are probably 15-30 devices that use these basic principles within 30 feet of every person who reads this post.

Clocks, speaker drivers, microphones, telephones, anything that plugs in and spins - like a hair dryer, blenders, the blower in your heating/AC system, electric pumps, the hard drive in your computer (in more than one way - to spin the platters AND to read the data), the alternator in your car...

Think about all of the things that we wouldn't have without ac voltage, wire, and magnets. It's also cool because both ends can be exactly the same. Something (air, water, steam) spins a device with a bunch of wire wrapped around it inside of a magnet. The magnetic fields "create" the power as the wire passes through them. The power is then wired to something that creates a changing magnetic field. The changing magnetic field causes something with wire wrapped around it to start spinning so that you can use it to do some kind of work. Transmitting circular motion through copper using the same components on each end...

Then you have transmitting pressure. Sound pressure waves from a singer press on a microphone pickup membrane, and it moves a tiny magnet inside of a coil of wire with some voltage running through it. The fluctuations in the "nomal" voltage travel through a wire into another coil, that moves another magnet that has another membrane attached to it that creates sound pressure waves that hit your ears and allow you to hear the singer. Pressure on one end transmitted to something that creates pressure on the other end. Again, with exactly the same components on each end (just different sizes).

Best Spock voice...
Fascinating.


Oh.. And Mark - Don't stand next to me. I'm copying off of the girl sitting in front of me.



M- M60s/VP150/QS8s/SVS PC-Ultra/HK630 Sit down. Shut up. Listen.
Re: You might think I'm crazy, but I'm not...
#77234 01/22/05 01:18 AM
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Some good points, Michael, but a couple of them need further discussion. The peak-to-peak voltage of the nominal 120V AC waveform is actually about 340V, rather than 169V; the peak voltage is +170V rather than +85V and drops to -170V. As you point out, the nominal 120V figure refers to RMS(root mean square) voltage, not peak voltage. The relationship between them on the AC waveform is that peak voltage is 1.414(square root of 2)times the RMS voltage, which is a type of average voltage, but calculated in a special way: the values of the voltages are squared and then added and averaged, with the square root of that average then being used as the RMS value. Seems like a lot of work, but the computer doesn't mind, and the RMS voltage is generally accepted as a more effective measure for use in power calculations than either peak voltage or a simple average.

As I previously commented, speaker wires are essentially immune from interference in home usage and no special shielding or precautions are necessary. For example, Blue Jeans Cable points this out at the beginning of their speaker cable discussion . What has to be taken into account is that the current in a speaker wire is on the order of a thousand times stronger than that in an interconnecting cable operating at low voltage into a much higher impedance than the speaker impedance. It would take an extremely strong electromagnetic or radio frequency interference field to cause a problem with speaker wire, and these almost never would exist in the home. So, the precautions listed, which are often suggested for protecting interconnecting cables, especially if they're not well-
shielded, aren't necessary for speaker wire.


-----------------------------------

Enjoy the music, not the equipment.


Re: You might think I'm crazy, but I'm not...
#77235 01/22/05 03:28 AM
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Right now I'm watching Modern Marvels on the History channel and the subject is magnetism. Very interesting stuff. I did feel smart when they mentioned how magnets are used in every piece of your home entertainment system, clock, computer, telephone, DVD cover...

Re: You might think I'm crazy, but I'm not...
#77236 01/22/05 09:21 PM
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I always wonder what we don't yet know about magnets and magnetism. At some point down the road scientists might discover that they cure diseases, provide unlimted power, nullify gravity, or something else really cool like that. And I'll be dead and won't get to see it.

JohnK, Yep, good catch. I was writing, and thinking about the signal as a positive half and a negative half. I plopped .707 into equasion to calculate peak voltage instead of 1.414 to get peak to to peak for the whole cycle. I plead "guilty with an excuse" - It was after midnight, and there were a few containment errors with some of the beer bottles around here earlier that night.

The article that you mention is correct, but it really has nothing in common with what I am talking about. It states "The low impedance of the circuit also tips the balance of concern from capacitance, which is important in interconnect use, to inductance, which, while a concern, can be controlled only to a limited degree. "

The "inductance" that the article is talking about is the electrical behavior of a coil of wire in resisting any change of electric current through the coil. A capacitor has "capacitance" which is the behavior of a capacitor in resisting any change in voltage. All cable, wire, etc. has some of each because they are unwanted properties that are unfortunately, laws of nature. They simply can't be removed. Mother Nature won't let them.

An inductor is a coil of wire (some wound around tubular cores, others around donut shaped cores depending on the inductance rating).

What I was referring to was "induced voltage". Whenever any piece of held stationary inside of a changing magnetic field, some voltage will be induced into that wire. It is another one of those laws of nature.


M- M60s/VP150/QS8s/SVS PC-Ultra/HK630 Sit down. Shut up. Listen.
Re: You might think I'm crazy, but I'm not...
#77237 01/22/05 10:03 PM
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Actually, magnetism can nullify gravity. On Modern Marvels there was this experiment in which a frog was placed in a container and some magnetic field (I didn't really pay attention to the science jargon) disabled gravity and the frog was weightless in this mini-chamber. I'm not sure how advanced this gravity nullifying magnetism is but I bet it wouldn't be too far into the future. Magnets are truly amazing.

Re: You might think I'm crazy, but I'm not...
#77238 01/23/05 02:18 AM
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Nullifying gravity with magnets is actually quite easy if you're taking about an isolated area. Nullifying gravity over a large area is quite a bit more difficult. The catch is that whatever you're trying to negate the gravity of HAS to be affected by magnetic fields. So, for example, you couldn't negate the effects of gravity on a rubber ball or brick but you could negate the effects of gravity on a lump of iron.

Re: You might think I'm crazy, but I'm not...
#77239 01/23/05 06:50 AM
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Right, Michael; when I referred to the "beginning" of the Blue Jeans discussion, that meant just the first two sentences where they comment on the practical immunity of speaker wire from interference. The rest of the paragraph goes on to discuss inductance, capacitance, resistance, etc. in, as you say, a context that has nothing to do with the speaker wire interference point at the beginning.


-----------------------------------

Enjoy the music, not the equipment.


Re: You might think I'm crazy, but I'm not...
#77240 01/23/05 02:42 PM
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I saw that John, but since it was speaking about EMI and RFI I just didn't make the connection. I tend to categorize EMI (electro magnetic interference for everyone else) into 2 categories: EMI that you would EXPECT to have in a certain location, and random EMI that just seems to show up unexpectedly. I would never intentionally run any data or audio cable over a flourescent light fixture. (They need to change the name of those from "light fixture" to "bad electrical noise generator that can be used to light up a room when you install the optional light tube".) They generate huge quantities of both EMI and RFI (radio frequency interference). I'm pretty sure that they are also known to cause cancer in the state of California as well. If you live anywhere else in the world, you are safe.

I agree with the article to a certain extent, but I would like to see "practically immune" changed to something like "substantially resistant". I find it funny that their description of the Canare 4S11 conflicts to a small degree with the first 2 sentences on the same page. "When conventionally wired, star quad speaker cable has the advantage of reducing the EM field around the cable, which will tend to diminish the effect of the signal in the speaker cable upon nearby interconnects--though this is not, in most applications, a significant concern.". Uh Oh... Here we go again. Now they are saying that the speaker wire is the source of the EMI, and that the interconnects are the things that you need to worry about in terms of getting interferred with. I give up. So should they. It's pretty hard to diffrentiate your product from the other guys' product when neither one of you can improve it beyond the limitations set by mother nature and the laws of physics. Why do I keep referring to mother nature? Because we (humanity) have only been able to study the laws of physics HERE. Just one environment. The "rules" could change substantially elsewhere, like outside of the Milky Way galaxy. Call Leonard Nimoy. We need him to take it from here...

The bottom line is that we live in an imperfect world. Interference is a fact of life, and due to certain laws of nature, we just have to live with it. We can eliminate some of it and deal with the rest of it. Speaker wire companies (and power cord companies) have to stretch the general population's understanding of science and the English language to the hilt in an attempt to convince you that they have the better product. Copper is copper. The copper in your water pipes will conduct an audio signal just as well as the most expensive speaker wire on the planet. Period. (I would recommend melting it down to an easier to work with form before testing - like wire.). What are they going to say? "We use the same damn copper as everybody else. Our wire bends just like everybody else's. If you put our wire in a bad place, it might just decide to act like an antenna, just like everybody else's. Ours has a coating on the outside, just like everybody else's.". The only real differences between speaker wire is found in the construction. Bare wire on each end is the "best" you can get from a strictly technical perspective (physically connected permanenty - soldered to the post would be "the best" with zero connections). If you are buying wire with connectors, pay more for wire with better connectors. If you are buying wire to pull through walls, pay more for the teflon coated stuff that makes it slide more easily. If they will be exposed, buy pretty ones. If you have to run them in parallel with your power cords, buy twisted ones, or go get a fancy, twisted, power cord and use regular speaker wire.

Uh... I'll stop there. Seems to back OT. This was a fun thread. Hey misfit, I hope your system souds nice!


M- M60s/VP150/QS8s/SVS PC-Ultra/HK630 Sit down. Shut up. Listen.
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