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In Reply to: Some questions on double blind testing. posted by Phil Tower on November 12, 2002 at 03:10:40:
I think a lot of folks aren't even interested in the answer. It's a "been there, done that" proposition. My own epiphany after 30 years of messing about with this stuff came when, just for grins, I swapped a pair of "coaxial" style interconnects with a pair of Goertz Micropurl interconnects that connect my CD player to my integrated amp. I had bought the Micropurls new for my phono setup (they're not expensive) and I thought, just for the hell of it, let's swap these in for the equally non-expensive DH Labs interconnects I've been using with the CD player. BOOM! Immediate and obvious difference. Stereo image much more "focused" high frequency transients (cymbals on a drum kit) much less "spitty" and more cleanly rendered. I did this over three successive evenings, with differente CDs. Always the same result. Scientifically valid? No, no DBT. Am I satisfied there's a difference? Absolutely. Did I hear differences between my Rat Shack interconnects and the DH Labs (of similar design) when I bought the DH Labs? Nope, not that I could be sure of.From reading your post and the many others that, in varying degrees advance the "wire is wire is wire" point of view (and advocate increased use of DBT's to "prove" it), it seems that where everyone starts to go off track is that their knowledge of electricity is limited to what they learned in junior high school science class when we studied direct current electricity. The relevant properties were voltage, amperage and resistance; and we learned that a thicker wire carried more amperage than a thin one.
You can recognize these people around here: they're the ones that talk about the "gauge" of the wire and the length as the relevant factors -- since those relate to total DC resistance and amperage.
Unfortunately, audio is AC, so there are other wire properties that are relevant: inductance and capacitance. These are not a function of gauge, but a function of the cable's design, insulating materials and so on. So, the short answer is that two cables of the same length and gauge can have vastly different capacitances and inductances; so, for purposes of passing AC, they are not the same.
In my example, the DH Labs cable is probably fairly high inductance and low capacitance. (Since were talking interconnects with miniscule currents; differences in gauge aren't relevant.) By constrast, the Goertz cable is made of two thin ribbons twisted together and separated by a thin insulator. It is relatively high capacitance and very low inductance. So, in a relevant sense, it is very different from the DH labs cable, even though if all you were doing was passing a 100 milliamp current of 1 volt DC, the two interconnects would be "the same."
Of course, the input and output circuits of components are not of similar design. So when you combine those differences with the differences among interconnects in terms of relevant electrical properties (not just DC resistance), it should come as no surprise that they sound different. Notice I have not said a word about more esoteric concepts like "skin effect," "self-inductance," "time delay" and so on.
The big question is: can a particular set of cable parameters be identified as consistently sounding better across a variety of components? The Goertz people claim that a low "characteristic impedence" is it; but "characteristic impedence" is an AC property that is always expressed at a particular frequency; and the Goertz people don't tell us what frequency it is at which characteristic impedence should be low. In practice, what that translates to, in their cables, is cables that are low inductance and high capacitance. Another cable with a similar configuration (obviously designed not to infringe on Goertz's patents) is the Analysis Plus oval cable. I don't think AP is quite as forthcoming with their characteristic impedence specs; but I could be mistaken.
Whether or not that low characteristic impedence is the holy grail of cables is the secret of cable makers, including our "own" Mr. Crump. . . .
Follow Ups:
From reading your post and the many others that, in varying degrees advance the "wire is wire is wire" point of view (and advocate increased use of DBT's to "prove" it),Just for the record, there is nothing in my post that even remotely suggests that I am advancing the "wire is wire is wire" point of view. Moreover if you search the archives here under my current “Phil Tower” moniker and my prior "pctower" moniker and all of the archives at AR under “pctower”, you will not find a single post of mine that even comes close to advancing such a point of view. I have been using after-market cables for over 20 years, back to the very first MITs, Monster, Audioquest and FMS Blues. In selecting my current cables I auditioned (sighted) well over two dozen different brands of cables (including Goertz Micropurl interconnects) over a two year period before selecting my current collection of cables.
I’m curious if you checked out my system before writing your post. It absolutely amazes me that the simple act of raising a scientific issue regarding objective verification of actual sonic differences between and among different cables leads people to automatically label the person raising the issue as a proponent of the “wire is wire is wire” point of view.
The context of your original DBT post at the top of this thread was about wires. Now, you tell me that you recognize -- and pay for -- the difference between wires. Why, then, the interest in DBTs for wires, since all that a DBT will ever establish is the existence of a difference -- something that you already acknowledge exists?I could personally understand someone's interest (because I share it) in the use of DBTs to verify the efficacy of some other tweaks, such as isolation platforms for solid-state electronics, "resonance control devices," demagnetizers for aluminum CDs, etc.
But I have to say, that it appears to me that you're admitting that you launched a thread asking a question that you already know the answer to: Why do people resist using DBTs to establish that differences between wires exist?
The answer is that people resist that for the same reason they would resist conducting a DBT to prove that the sun rises in the East in the morning: it would merely establish the truth of a widely held proposition.
The context of your original DBT post at the top of this thread was about wires. Now, you tell me that you recognize -- and pay for -- the difference between wires. Why, then, the interest in DBTs for wires, since all that a DBT will ever establish is the existence of a difference -- something that you already acknowledge exists?All I have told you is that I pay for after-market cables. I haven't told you I recognize anything at the level of scientific verification.
I pay for after-market cables because the ones I use produced, what I perceived to be, an improvement in my system, and the perceived improvement was consistent and significant enough that I was willing to pay for it - Steve Eddy refers to that as the "hedonistic" approach to audio - it's purely subjective. But the fact that I make those personal choices based on what brings me pleasure, says nothing about what I believe, from a pure dispassionate scientific view point, as to actual audible, sonic differences. When I choose to buy after-market cables I'm not concerned about the science of the issue or whether my perceptions of improvement are real or imagined. I care only about one selfish thing, and that is my pleasure level.
The fact that I choose cables that way should not preclude me from approaching the scientific discussion of cables from a dispassionate viewpoint of simply wanting to get to the truth in a scientifically valid manner.
In order to provide further elaboration on this, please refer to this other post of mine:
http://www.audioasylum.com/forums/prophead/messages/230.html
I believe that the questions I'm raising in this forum can stand on their own, without any reference to how I make my own personal decisions, or what I do behind closed doors in the secrecy of my own sound room. The reason I referred you to my system is simply to reinforce my statement that I have never attempted to advance the "wire is wire is wire" view point. All I'm attempting to advance at this forum is a dispassionate search for the truth.
From a purely scientific view point, which I understand is the orientation of this forum, the only position I take with regard to the question of whether cables of similar gauge and length can be responsible for actual sonic difference is that, to the best of my knowledge, no one has ever demonstrated under valid, control conditions that at least one human being can detect sonic differences when two different cables of similar gauge and length are switched in and out of a system. If you or others have information to the contrary, I am totally open to valid scientific evidence on either side of the question.
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