El: It doesn't look like Rsbeck is going to accept my invitation to put his own theories to the test and provide us with his own unbiased testimony as to the outcome. As such, i can send you both sets of cabling, which would allow you to continue to bi-wire the system as you are now. Only thing is, one set would have spades and the other would have bananas. Would this work with your specific amplifier and speaker connections? Sean > |
Sean...I think I will skip the biwire thing for this test. Let's minimize the number of variables. I don't think that spades work with Maggies. (I am actually a "bare wire" guy, so I'm not up on all the various terminations). In addition to the Maggies, I will try the wires with my Madisound Odin speakers, which have more extended high end. Ed. . |
>>i'm simply saying that i think it provides a very audible contrast to the sonics of zip cord.<< That isn't the issue. The issue is whether or not .1 dB down at 20Khz or .25dB down at 22 Khz is audible. You claim it is -- that if one has good ears, one can hear this. I say that if you can pass such a test, you can make a lot of money on the county fair circuit. Nordost and Zip Cord may or may not sound different, but what would that prove? This is a ridiculous way to test to see whether or not you -- SEAN -- can really hear .1dB down at 20Khz and .25 dB down at 22 Khz. It seems obvious to me that you are trying to pull a switch -- trying to get others to take an irrelevant test -- because you know that you can do no such thing. In any case, I think it would at least be more responsible if you gave out complete information and let people know that when you are talking about this "roll-off" you are talking about .1dB down at 20Khz. I trust that few will remain interested in your allegations if you give this information -- and I also suspect this is why you leave this information out. Now, if you want to compare Nordost and Zip Cord. What are you comparing? Where are the frequency response charts for the Nordost cables? RLC? Are we assuming the Nordost yield a perfectly flat response? Based on what? If they don't yield a perfectly flat response, then how is it relevant? It isn't. If you want to see if you can hear .1 db down, you need to measure it against flat, you need exact level matching and you need to do it double-blind for it to carry any weight. Too many studies have shown that sighted tests are unreliable because of the placebo effect. Any test that doesn't rule out the placebo effect carries no weight. Similarly, anecdotal testimony carries no weight. Conducting a sighted comparison against a cable with unknown measurements without exact level matching and claiming it is a test to see whether .1dB down at 20Khz is audible not only carries no weight, it is pointless and silly. |
Rsbeck: You aren't looking at the big picture and apparently refuse to do so. The amplifier is not driving the speaker cables independently of the loudspeaker load, it is driving / responding to the complex impedance that each individual cable / speaker combo presents to the amp on the whole. This is why there are sonic differences in cabling i.e. the complex impedances vary with frequency and each amp responds accordingly to that load. Based upon how stable the amp is into various loads, not only can frequency response be altered, but so can transient response, distortion characteristics, etc... Nelson Pass has had all of this data publicly available and documented for appr 27 years now. Then again, i guess it takes a long time for news to go from one corner of the flat earth over to the other corner. As such, i will not waste any more of your or my time debating our very different points of view. You are obviously stuck in one mode of operation and afraid to think for yourself beyond what someone else has told you to be the "truth". Studying something as simple as Thevenin's Theory might be to your benefit in the long run though. The fact that the nominal impedance of speaker cabling can vary from a few Ohm's to well beyond 100 Ohm's should be enough to make one wonder how they could perform equivalently in a very low impedance circuit. Such silly things as voltage to current ratios might explain a few things too. Then again, that was alluded to in the 27 year old article that Pass published too. El: Sorry for not contacting you sooner, but as noted elsewhere, i was having major computer problems and decided to enjoy the nice weather rather than try and fix the computer. Drop me an email with your mailing address. Sorry for the delay, but i probably won't get these out until Tuesday morning. Sean > |
The characteristic impedance of a cable is Z=sqr(L/C). The propagation velocity is V=1/sqr(LC), and also V=speed of light/sqr(epsilon times mu). Massaging of the equations of a coaxial run provide us the relation: L times C = 1034 times the dielectric coefficient. The coaxial run is the most efficient use of the structure, anything else will not provide velocities as high..this is because the inductance of non coaxial runs is higher as a result of failure to confine the mag fields to within the structure. It is useful to calculate the LC product, divide by 1034, to determine the EFFECTIVE dielectric coefficient of the wire system, as this is a direct measure of both the speed of propagation along the wire, and the actual line storage. Note that if that product is less than 1, the L and C data are in error...less than 1 indicates faster than light prop...a no no.. L in nH per foot, and C in pf per foot, of course.. As it turns out, the point of minimal line storage occurs when the characteristic impedance of the cable matches the load..so, in theory, an 8 ohm speaker would work best with an 8 ohm cable impedance..this of course, is not because of reflections per se, but rather, just simply from the calculations of inductive and capacitive storage... E = 1/2 L I squared, and E= 1/2 C V squared. As it turns out, this energy storage is a lagging one for both the inductance and the capacitance..meaning, the energy delivered to the speaker will be slightly shifted lagging. At 10 Khz, this storage minima is actually about 4% of the delivered power. And, this 4% is delivered to the load 90 degrees out of phase with the primary signal current.. For audio, given the power slew rates at the output terminals and the wire lengths involved, reflections are of no concern. One would be better off examining human localization capabilities with respect to wires, as 20 Khz isn't enough, one must look for time shifts on the order of 10 uSec, as that is well within our ability to hear... Grain boundaries within the metal do not cause reflections...at any frequency..all they can do is add to the dissipation along the conductor. Since the mean free path of electrons is 3 times 10 (-8) meters (wish I could do exponents on this forum), adding a coupla more relatively speaking, does nothing to anything..can one hear say, 1000 more collisions on a meter of wire, when the electron collisions are 30 million per meter?..and the noise is entirely uncorrelated? When the surface texture of the conductor approaches the wavelength of the signal, then problems arise..but at audio, nada.. As for dielectrics, the secondary parasitics within the insulations are very significant when one is hi-potting a large capacitance, or making a sample and hold circuit..but, for speaker wires, I'd have to see the parasitic numbers, to figure out energy balance, and level of effect.. As for listening..don't bother with the standard 20 to 20K JND numbers...unless of course, your intent is to establish differences with only one channel playing. For stereo, there is just a tad more at play here.. While I remain open to either possibility, I would insist on realistic scientific explanations... Cheers, John |
