The Science of Cables

@douglas_schroeder Ok, so I am confused by these two posts. It might be a benefit to re-post these posts in the Shroeder Method thread: https://forum.audiogon.com/discussions/doug-schroeder-method-double-ic

But back to my confusion. In the first paragraph of your first post, you mention the set-up: "I reverted back to my MF transport feeding the Exogal Comet DAC and Ion Power DAC combo." From this description, I gather the transport is only sending digital data as an output signal. And from this statement from your second paragraph, "I once again used the Schroeder Method of Interconnect Placement with the transport’s AES/EBU output," I gather you are using an SM digital AES/EBU interconnect cable between the transport and the Exogal DAC. And in the final paragraph of your first post, you mention that "AES/EBU with this unit is very sensitive to such cable changes." What is "this unit," the transport or the DAC?

But then in your second post above, you clarify the SM IC is being used in the following manner: "AES/EBU is an analogue output." So my confusion is whether you are promoting the SM AES/EBU XLR IC, originally intended as a digital cable, as an analog cable.

Tara22 thanks for the EM and Physics... very interesting.

Its important to remember that “Objective Measurements” are dependent on the mathematical model of the problem or physical reality one is attempting to explain, predict or understand.  

Each model has its own limits since by nature mathematical models are just that mathematical models and are not reality itself but a model of that physical reality.

Thats not to say that they are not useful or that they can give us great understanding...

I agree that performance metrics are important and may give us a means of comparison... the question is it a valuable metric of performance/ comparison.

let me give you an example from my experience in a different field. 

I am not an electrical engineer, I am an ex fighter pilot and now a commercial pilot.  Flying fighter aircraft required one to fly the aircraft to its max design limits (the edge of the envelope) where the flight characteristics may not be stable or predictable.  

I also have a degree in Aerospace Engineering,  Obviously we build airplanes and electronics based on mathematical models but also accomplish extensive testing to verify the stability and performance of aircraft.

Subsonic equations of motion (EOM) and supersonic equations of motion are quite different,  subsonic incompressible flow fields use some of the the Exact same equations used to describe Electo-magnetic phenomena
...Hence each uses the same math to describe different physical problems, but each have their limitations.

When designing transonic and supersonic aircraft the EOM become more difficult to solve as they are non-linear and simplification and assumptions become necessary as well as different ways of modeling flow fields ( finite element analysis).

As the speeds get higher toward hypersonic flight physical properties, thermodynamics etc  that were insignificant in very low speed flight become much more significant.

As a fighter pilot we needed to be able to assess the enemy’s aircraft performance in relation to our own aircrafts

Some of the basic numbers of comparison gave us a basis to Accomplish a performance comparison of the flight envelopes of my own AC and the enemies AC

for example :
Min and max speed,  max altitude, wing loading, engine to thrust ratio.  Range payload etc.

Each of these gave us some measure of comparison but when it came to Air-to-Air combat they only described part of the picture.

Someone smart came up with an Energy Analysis to compare aircraft it was called an Em diagram... which is a plot of the flight envelope bounded by the aircrafts structural G limit, Lift, Drag, Thrust and speed limits etc.  Each diagram was for a specific altitude. As the altitude changed so did all the variables used in creating the Em diagrams.

The bottom line is that all of the performance characteristics were interdependent and variable.  The diagrams gave us a tool to compare but it had it limits... we got an idea where we had a performance advantage and where our weaknesses were.  We would use these Em diagrams to capitalize our own aircrafts advantages when engaging enemy aircraft.  We would attempt to engage at speeds and altitudes where we had a tactical advantage.... but in the end it was such a dynamic and fluid environment that the Em was only a way to help analyze and hopefully give us a way of surviving and hopefully dominating enemy aircraft in a fight.

Flying fighters required you to “become” the machine you were flying in-order to max perform it.  

Simply said it is an art form

so what does all this mean?

I’m wondering if cables are subsonic, supersonic or hypersonic... IE are there  “significant-digits” in the physics that are important... ones that we can actually hear?

I’m thinking that we “objective measurements” give a some means of comparison, ( like you said resistance, capacitance etc )... the engineer in me says yes 

Resistance, capacitance etc....I hear Min/ Max Speed, Max Altitude, Thrust-to-Weight ratio etc.

So what you’re asking is there an Em diagram for cables?

maybe the answer is it requires both... an Em diagram and Art

You're going to catch some flak for that. 😄

But, I agree that basic measurements are one thing, and just that. Something like an Em diagram would be a much needed step in the right direction. 

People tend to forget that the data, or graph, is not the music. It's a crude representation of the event. A guideline, for sure, but it can always be massaged.

All the best,
Nonoise

My head hurts. I am glad I don't need an aerospace engineering degree to enjoy my audio system.

"AES/EBU is an analogue output."

Confused about this as well.