It is definitely possible to wear out copper..however, it requires current densities in the 10 power 5 to 10 power 6 amperes per square cm...IIRC.
Cheers, John
Well, I do have a massive amp, of course
What would happen at those current densities? Instant vaporization?
Well, I do have a massive amp, of course
What would happen at those current densities? Instant vaporization?
No, not instant. Maybe a hundred microseconds or so??
Electromigration. The movement of copper atoms caused by the bumping of the electrons into the lattice. The momentum of the electron pushes the copper atom in the direction of the electron current. It happens on LSI chips when the aluminum traces are too small for the currents being used, it makes hillocks and breaks the traces. Pics can be found on the web.
It really happens at superconducting solder joints if the cross section of the solder is insufficient for the current. LHC type stuff. Solder can only take 10 power 5 amps/cm before the tin or silver gets pushed by collision momentum.
It cannot happen with any wire at room temperature, in any circumstances whatsoever. It is an effect that can only happen at the scales of the aluminization on semiconductor chips, and when superconductors are involved. Normal wires are incapable of supporting such current densities and not melting instantly.
Just buy some more? What's the problem? Or even collect your own...
jn
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When that green/brown patina develops on the Home Depot multistrand as the surfaces oxidize, the sound gets pretty 'old', too.
Interstrand rectification/(surface) conductivity changes, photoelectric effects and skin effect changes due to oxidation are not our sonic friends, even at the millivolt range. Of course, the 'perfect sound forever' group may disagree, but it is doubtful whether they even consult their ears to make these judgments.
Interstrand rectification/(surface) conductivity changes, photoelectric effects and skin effect changes due to oxidation are not our sonic friends, even at the millivolt range. Of course, the 'perfect sound forever' group may disagree, but it is doubtful whether they even consult their ears to make these judgments.
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I have a problem, now.if my actual amp have an exceptional 300V/µs, i have added a cap to filter the input signal upper than 40Khz at 6db/oct in order to get rid of electronic IM distortion. So the speed i can hope with normal level signals is too slow to see your cables differences. Reason why i asked a sin wave at 40Khz. (a square wave is a combination of fundamental and harmonics of them). Any way, and as i said, my moving coil not move at 80Kz (first harmonic of 40, right ?)
Image location is calculated by the brain on several factors.
The first one is the difference of magnitude (level). That's how works panoramic button on the desk used to produce the record i'm listening at this moment. And your balance button if any. (balance of your amplifier is 5% tolerance in the best cases, and...)
But measuring the difference of level it needs to move an instrument in a way you can feel it how much more a magnitude ?
The second is the difference of phase of the fundamentals (not the harmonics !!!) between the two channels. That's how works microphone's couples and artificial heads. But my cable are the same length on both channels. And, even if they have a wide difference of length, i cannot hear the difference in localization of a central source, because electricity is too fast comparing at the speed of the sound, it does not make a difference (Scale, range, again).
Ears is not sensible to the phase between harmonic components of a sound. But to the coherence of them. And it is happy, because the time propagation of sound in the air.( Bass will reach your hears in phase with the loudspeakers, treble with several sinusoids of delays )(sorry, my English, again). The important thing is the group delay. I wonder if your differences affect the linearity of the group delay in the 20 20000 range. Anyway, ears evaluate distances is ms range, not µs. Happy, as simple humidity changes in the air makes more than µs's.
Some of the readers may-be knows that the brain use an other very mysterious way to localize the source of the sounds. It is progressive response curve changes all along with reverberations changes. You can produce a vertical localization and modify as sound in a way that, listening to the same mono source instrument, you can produce the effect that the source moves vertically and in distance, going from front to the back of your location, and up and down. Just in changing the response curve of a same source in a continuous and fixed way (remember Fletcher and Munsen curves) , stimulating what happens with your head movements. (ears had not a linear response in the space volume). But it is cultural, it only works with sond objects your brain knows and recognizes, and with coherent and continuous changes. If you stop moving the effect, your instrument, that you believe right at the vertical of your ears will sound in between your ears again.
And the scales, again, of those effects ! Their appears with a X100 magnitude at least of what's can happens in a loudspeaker's wire.
Well, that's what i says. I do not care about 0.1db constant accident at 20khz (that my ears cant' hear), when my loudspeaker produce 10 db of accidents in the middle of their response curves (around 3khz, where my ears are the most sensible). 10db or more !!! That's what i don't care about wires, and i prefer to work on my loudspeakers with a huge magnitude effect ;-) I do not care about µs delays, when my loudspeakers have ms of accidents.
I don't believe in measurements, i believe in measure's effects i can correlate with my ears.. I do not believe in my ears, in a way, i need to correlate with measurements to understand phenomenas, and can modifies them in a useful way. And i don not care any changes i can feel at a moment, and not 1 minute later. (blind tests)
That's the problem with cables: I do not ear any significant changes (with same resistances self and capacity)comparing to others aspects. The changes that cables can introduce in the channel is too much degree of magnitude away of the loudspeaker's imperfections.
I don't want to argue for the pleasure, i want we all agree with this so evident arguments, and stop to let the door opened to people selling cables at 3000 $ for believers in Ghz response curves, and magical color effects, see what i mean ?
Can wee agre on that ?
Can we conclude, in the actual situation of technology, along with Peter walker, that the best speaker cable is the one witch conduct electricity, and give good advices about reasonable diameters of coper, prices, consistency of isolation (capacity and dynamic changes of capacity) and lengths ?
And help believers of memory effects, oxygen free material, mysterious isolation material etc. to cure their pathological fears ?
Ps: It is very funny to see that most of the sellers of those mysterious 3000$/m cables refers early or late in their arguments to this legendary figure in audio.
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No one is going to prove anything when it comes to the imaginative levels any individual has. The conclusion is make your or decision on what matters (Meaning you can either be a believer or you can follow current science and measurements). Just understand that any IC or speaker wire could possibly increase the overall SQ of any system a fraction of a percentage point. If you can convince yourself that fractional precentage gain is actually a mountain full of difference then more power too you.
I say unless the room and speakers are PERFECT why even fuss over any cable choice
Room and speakers effectly control 99% of the SQ so focusing on anything else just seems inefficient to me.I mean there is a new thread in the multi forum asking about a cable to alter the response of a speaker. That is just a crazy way of thinking period. If people need cables to change response why don't they just go back to figuring out how to have a better speaker design in the first place ??
I buy all my cables (ICs, wire) from PE, Monoprice.com and BJC.com. I buy usually when there is a great sale going on. Lets just say that IF your cables even start costing close to 5% of your speaker cost you haven't done something right. I can see some opinion saying, "well you guys do not spend $$ on audio". I just bought TAD CDs and BMS CDs for a total cost of $4K alone!!! I have spent $10K on amps and pre/pros that last 2 years. Im sure others spend $50K or whatever but compared to 99% of the world even my choices and setups (I have 3 in my house) are way beyond what the average person will ever own.
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+1, the debates about splitting hairs fractional changes and mostly inaudible differences is mind numbing. Not only does the speaker have 1000times more issues the room also dominates the discussion but yet I see pictures of so called quality speakers in crap rooms with $5K cables
The owner posts like he has the perfect setup and he thinks his cables solved his issues. How can people even post with a straight face when speakers and rooms are generally far from perfect???Damn, I have to save that opinion. Expressed pretty much how I feel and I could never clarify like you just did. Thanks!
OK so nobody else has pictures, here's one. On the left we have 8 Ohms at the end of 15 nsec of 100, 50, and 8 Ohm lossless ideal transmission line and a perfect amplifier. On the right I added ONLY a very modest Zobel and L that you would find on just about any SS amp (500 nano-H, .1uF, 4.7 Ohms) at the output of a still ideal amp.
So please tell me how these steps are visible using an off the shelf $100 amp?
Also please note time scale. Everything interesting is done in <1usec.
EDIT - JPEG farkled it a little, there are none of the little spaces.
So please tell me how these steps are visible using an off the shelf $100 amp?
Also please note time scale. Everything interesting is done in <1usec.
EDIT - JPEG farkled it a little, there are none of the little spaces.
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Besides the fact that the "interstrand rectification" is entirely fictitious, the filled vinyl insulation does an excellent job of preventing corrosion. My wires are nearly 10 years old, and when they are stripped, the copper is nice and shiny.
Maybe I misunderstood him, but MT seemed to be claiming that 'matched' speaker lines sound better and appeared to be offering the absence of pulse reflections as evidence of this?jneutron said:
Now that people have said that some audio amps do generate RF, perhaps we can agree that they should not either emit or respond to RF. In this case the RF properties of the cable cannot be relevant. Given real amps may be different, can we agree that some speaker cables may sound better for audio because of their RF behaviour. This means that cable manufacturers ought to be saying "Buy my cable if you have a lousy amp which responds to RF, because my cable helps to suppress this (which should not be happening anyway). It has no relevant audio effect apart from this. By the way, if all reasonable cables sound the same to you then this does not mean that your ears or equipment are poor; on the contrary, it probably means that your equipment has been properly designed and built." I'm not holding my breath!
Surprisingly, he suggested that you could use dramatically different lengths of cables, which is in direct contradiction to jneutron's worry about microsecond-order time differences.
If you wanted to prove that it makes no differences at all, you perfectly reached your goal .
Please, and again, can-you publish a complete period we can have an idea of the scale. ;-)
After that, i will publish a picture of the same square wave out of a Class D amplifier well known for his sonic qualities ;-)
Oh, too, can-you publish the same test, but measuring the signal with a microphone in front of your tweeter ? If you can see ANY difference, i eat my hat.
Concerning phases, I take good care, when it is about aligning my loudspeakers for best group delay about 1µs differences, witch correspond to 0.3mm alignment differences between speakers.;-)
I never play basses in the same time than medium, of course, because the movement of my moving coil is 10 time larger !
Sy -
I will, when time permits, demonstrate interstrand rectification in speaker wire using commonly available test equipment. One of several ways to do so that comes to mind would be to measure any difference in conductivity down to parts in a million depending on direction measured.
Then you can masticate your chapeau at leisure after you complete your entree of Heckle and Jeckle.
I've got several dozen feet of Home Depot 12 Gauge speaker wire that is less than a decade old where the untinned copper conductor is no longer copper colored at all (it has clear vinyl molded on insulation so I can inspect its entire length). It's sort of a brownish greenish gray from a distance. And it's always been indoors in a temperature controlled environment - IOW, representative of the type of speaker cable you are talking up.
It doesn't sound nearly as good as it did when it was new, either. But it wasn't that good new in the first place. Just cheap, with the sonic compromises built right in.
I also have some old lamp cord that you may be interested in.
I will, when time permits, demonstrate interstrand rectification in speaker wire using commonly available test equipment. One of several ways to do so that comes to mind would be to measure any difference in conductivity down to parts in a million depending on direction measured.
Then you can masticate your chapeau at leisure after you complete your entree of Heckle and Jeckle.
I've got several dozen feet of Home Depot 12 Gauge speaker wire that is less than a decade old where the untinned copper conductor is no longer copper colored at all (it has clear vinyl molded on insulation so I can inspect its entire length). It's sort of a brownish greenish gray from a distance. And it's always been indoors in a temperature controlled environment - IOW, representative of the type of speaker cable you are talking up.
It doesn't sound nearly as good as it did when it was new, either. But it wasn't that good new in the first place. Just cheap, with the sonic compromises built right in.
I also have some old lamp cord that you may be interested in.
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I have read my post at least 5 times, and I still do not know how you arrived at that question.
The answers: It does not, and....it does not.
The "frequency dependent delay" is the result of the speaker having a different impedance at different frequencies.
Imagine you are using a 4 meter length of zip, it measures 100 ohms.
If your speaker measures 2 ohms at 50 hz, it will have a response delay at 50 hz as a result of the line to load mismatch. If it is 20 or 50 microseconds, so be it.
If that same speaker measures 100 ohms at 5 Khz, there is no line to load mismatch, so no delay (to speak of, nSec is of no concern).
So your speaker is delaying the audio frequencies based upon the speaker's impedance at the specific frequencies.
Problem is, how can one measure those levels of delay accurately?? I measure this type of thing for a living, and I have to admit that this level of time accuracy is very, very difficult even into a pure resistor..
Your post is in essence, along the correct lines.
I have used the term IID. This is Interaural Intensity Difference.
I have used the term ITD. This is Interaural Temporal Difference.
Both together are used by the human brain to discern the location of the source.
If one is attempting to use a stereo to create images in space, then it is important to make sure that the system is not capable of altering the parameters which we use to locate those images.
The graphs I presented before show the amount of change of those parameters which will result in a front to back movement of an image by a distance of 20 inches. I also have side to side movement graphs for the same 20 inches.
Further analysis can be performed to produce lines of constant "shift", as it were, so that one can determine the level of control of both ITD and IID required to maintain image stability to a foot or so through the entire 2 D soundfield. These graphs show that when both channels are delayed, any image which is not along centerline...will shift in depth and direction EVEN THOUGH both channels are delayed symmetrically. While counterintuitive by nature, it is what it is... Mono of course, would not suffer this, nor an image at centerline..
Personally, I use #14AWG from HD, #12-3 from Sam's Club, and even the #24 that came with my 5.1 system, as image stability of my music collection is not important to me. This doesn't mean that I do not understand the issues of course, just that it is not something I worry about.
Cheers, jn
Yes, I noticed that. My head tells me that somewhat different lengths make no discernable difference, but I must admit that I have equal lengths (of perfectly ordinary cable). Given that the speed of 'sound' in cables is about six orders of magnitude faster than in air, I suppose you can compensate for a 2m cable difference by moving one speaker about 0.002mm forward of the other. There will also be a miniscule frequency response difference due to different resistance, but this will be much smaller than drive unit and crossover matching errors.SY said:
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