SilverSmith Audio Cables Interview
Jeffrey Smith from SilverSmith Audio was nice enough to engage in an informative interview about his cable philosophies and self proclaimed sciences behind them. While his ideas about cables and signal propagation are unconventional, they do sell a very interesting story.
What transpires below is an informal transcript between Jeffrey Smith, Gene DellaSala and John Escallier. All content is provided here with permission. Read on to learn more...
Audioholics: Dear Silversmith Audio. I noticed some interesting claims on your products but also noticed no published specifications. Do you have published specs of these cables (R,L,C)? If so, how did you measure them? What distance did you separate the (+) and (-) conductors when doing this? Thanks.
Silversmith Audio does not publish the RLC specs of the cables because the relationship between the conductors can change. Consequently, the LC parameters are not constant. Also, RLC parameters, within the realm of most cable designs, have very little or nothing to do with why/how cables affect sound.
Audioholics: That's interesting. So what you are telling me is you have no control over RLC of your cable and it's a function of position by the end user. What cable metrics are responsible for the sonic signature of the cable? How do you measure this to improve the designs? How do you know when you reach nirvana?
You sound surprised! That's interesting considering you and others on your site have so diligently shown that RLC parameters can not be expected to influence cable sound for all but the most extreme designs. Those who argue that cables can not possibly affect sound most frequently use the same arguments you have presented.
Audioholics: We never argued cables cannot sound different. But we will argue that only badly designed cables DO sound different. Such is the case with many exotic cable vendor designs. Perhaps yours are an exception, but the fact that you don't rely on measurements to govern your cable designs is frightening.
Unfortunately, they do not continue deeper in to the true physics of electromagnetics and/or properly apply the concepts to discover what really happens in electrical flow. They use the simplified model of electricity, which is the water in a pipe analogy. In this model, electrons, like water, flows up the positive leg, and back down the negative. Engineers use this model because its gross assumptions and generalizations of electricity make low frequency, typically 60hz, circuit design and analysis very easy.
Audioholics: Can we stick to a discussion on cables, I'm an Engineer not a Plumber :-) Hmm so you seem to be doing some sophisticated analysis. What programs/tools are you using to govern your designs? I bet these tools (ie. TDR, Network Analyzers, Magnetics Analzyers,etc) were designed by the same engineers that you claim simplify analysis too much.
At low frequencies, those assumptions will not affect the ultimate purpose of the circuit. In the water in a pipe model, RLC parameters are the basis of evaluation, and it can be easily shown, as you have done, that cables do not have enough effect on over all frequency response or impedance to be sonically discernable. Using the low frequency model and that same reasoning, it is pretty simple to also show the since most amps, pre-amps, CD players, etc all have approximately the same specs and should all sound the same too. High frequency design is a different matter. In this realm, the wave guide model, in which the electrical energy in transmitted between the wires instead of inside them, must be used.
Audioholics: So what do you consider "High Frequency Design"? 20kHz ??? Most RF Engineers consider anything less than 1GHz DC. If you would like to discuss transmission line theory, I will be happy to entertain you. However, if you are trying to apply relevancy at audio frequencies, then you may wish to change topics as it would be like trying to make a fish ride a bicycle.
By high frequency design, I do indeed refer to work in the GHz range. The concepts very clearly show why a cable can have an audio impact. My cables are designed using those equations. If the equations are valid (as far as I know there have been no major changes recently in electromagnet theory), the cable design is valid. If you wish to keep the belief that transmission line theory has no bearing on audio, then you will never discover why cables make a difference. The concepts are there. They just have to be properly applied.
This is a much more accurate model of what really happens in electrical flow and describes, when properly applied, exactly why wires alter the signal enough to change your stereo's sound. It also predicts (and explains), interestingly, other phenomena:
1. A digital cable and a power cord, will affect the sound in exactly the same manner and for the same reason that the analog signal cables do.
Audioholics: And how is that?
Properly applied transmission line theory explaints it very nicely.
2. Lifting a cable off of the floor, depending on the construction of the floor, will audibly change signal transfer.
Audioholics: How so? So if I live in an apartment and are on the 7th floor for example, will the sonic signature of the cable be different? How does it change the signal transfer? Is it measurable? How do you know when you reach the right elevation for optimal performance? Do you use any sort of objective test tool to measure this? Is there any provable relationship in electromagnetics that validates this? What happens if someone lives in an underground dwelling? Theoretically if they placed their cables on the ground above them, they would be elevated, so would their sound be improved?
Properly applied transmission line theory explains it very nicely.
3. The changes caused by cryo treatment of a conductor will audibly change signal transfer.
Audioholics: Really, how does that translate into provable measurement? Does the cable have to remain in its cryo state to maintain the alleged improvement in sound? Why not build a cryo freezing device to keep the cables frozen all the time? Better yet, why not use a superconductor? I believe you can purchase some from a National Research Lab for a few billion dollars. Who cares about price, this is high end audio :-)
There are several changes that can be measured in a cryo treated metal. Plug one of them in to the proper transmission line equation, and, well, it becomes obvious. In fact, that parameter is also one of the reasons why my palladium alloy outperforms silver, copper, aluminum, gold, etc.
What does cryogenic treatment do to either the dielectric, or the conductors, which provides any change in characteristics that are measureable? When a pure metal is subjected to a cryogenic environment, the electron mean free path increases as a result of a drop in lattice collisions. Pure copper, in fact, will see it's mean free path extend to about 10 cm, and it's conductivity will increase three orders of magnitude. But, it is, to the best of my knowledge (and that of my co-workers) a process that follows a reversible path. We are unable to determine, by any tests that we are aware of, that a copper specimen has been subjected to a cryogenic environment. This does provide any parametric shifts which are capable of explaining a cryo change of any type. So I am unable to understand what parameters you would measure and use in a transmission line model. Only for alloys such as steel, where the lattice changes from FCC to BCC below the martensite start temperature, can we find evidence of a cryogenic induced transformation. Granted, I only work with liquid nitrogen, at 77K, liquid helium at 4.5K, and superfluid helium at 1.88K, and have no experience with the really cold temperatures.