connect 2 different wire gauge to pos and neg speaker terminal

Great post Al.

Geoffkait,  electric charge still travels back and forth inside of the wire between terminals hence skin effect still applies.  It starts for the copper at 20kHz at about gauge 18.  Al was only explaining difference between electric charge travelling back and forth (electric current) and energy delivery from source to load in form of electromagnetic wave outside of the cable.  Load has voltage drop between terminals hence we have electric field while current in the wire produces magnetic filed.  Interaction of these fields causes power draw by the load.  Source also has electric and electromagnetic fields that cause power output.  As Al stated this energy is delivered in one direction only in form of electromagnetic wave outside of the cable - from source to load.  Direction is determined by Poynting Vector.  Electric and magnetic fields are perpendicular to each other and determine direction of Poynting vector (direction of energy transfer).  It is also true for DC.

Dielectric constant of Teflon is about 2. Vacuum has dielectric constant of 1.

Yes, Teflon will slow down electromagnetic wave. Insulator will slow down electromagnetic wave by amount based on its ability to store energy - Permittivity. Dielectric constant is just relative Permittivity. This speed of electromagnetic wave thru typical insulated wire is about 60% of the speed of light in the vacuum. For typical cable it comes to about 5ns/m and it is exactly true for cat5 cable. There is no different electromagnetic wave for audio signals and other signals.

Geofkaitt, Yes, it is about 66%  = 5ns/m (I inverted it wrong).  Teflon is probably a little faster.  They also use foam Teflon to lower dielectric constant.  In addition wires can be in the hollow tubes since dielectric constant of the air is pretty much the same as vacuum (approx. 1)

Jea48, Dielectric can possibly cause distortion since it absorbs and releases energy.  Example of this is capacitor that is charged, discharged by shorting and then opened.  Voltage on the capacitor will start growing back from zero to many volts.  It is very pronounced in electrolytic capacitors.  It happens because dielectric stores and returns energy.  It is called Dielectric Absorption and is also related to Permittivity.  Returning voltage when signal has already different level can cause distortion.  Looking at the lines of audio cable I can say that price is proportional to dielectric used.  PVC, that you mentioned is pretty bad while Polypropylene is better, Teflon better yet and oversized tubes of foam Teflon are the best (Acoustic Zen Absolute IC).  How much of this is audible I don't know.  AZ Absolute sounded "cleaner" to me (more refined), but it can be placebo effect (I expected it).  Dielectric Constant also affects capacitance between wires. Capacitance of typical cable is around 25pF/ft while AZ Absolute IC is 6pF/ft.  Can capacitance of IC be a source of tiny distortion?
Al, what is your opinion on dielectric absorption in audio cables?  Can this be audible?

Thank you Al.  I'm not sure if AZ Absolute ICs are really better in my system or just sound better because of "expectation bias"  - either way outcome is the same  :)

Thank you Jim.  Al is known for his knowledge and willingness to help others.  He is also much better in explaining things.  Al, have you ever been a teacher?

From what I understand the movement of the current in the conductor is quite slow.... Correct?

Electric current is a flow of electric charge and not the flow of electrons.  (In fluids electric charge is carried by ions and not the electrons).  Number of electrons crossing given point defines amount of electric charge (current) passing.  Motion of electric charge is usually explained as a row of stacked balls in the tube - when you push them slowly they will move slowly but when you hit the first one with a hammer the last one will respond instantly - that's the speed of electric current (charge).  Of course there is plenty of space between electrons but "stacking" is not physical but electrical (electric charge).

As for the energy transfer on the outside of the conductor by electromagnetic wave - without it current in the wire alone would not explain energy transfer, since the same amount of electric charge comes and leaves the load (same current leaves and comes back to power supply).  Poynting vector is defined by Electric Field E and magnetic field H.  Amount of energy transferred is proportional to magnitude of both fields ExH.  Electric field is proportional to voltage while magnetic field is proportional to current.  Multiply them and you'll get the power P=V*I  (power over time is energy).  Current flowing thru the fuse causes voltage drop since fuse has resistance.  This voltage drop creates electric field across the fuse - without this voltage drop (fuse resistance equal zero) there would be no electric field and magnetic field (current) alone cannot deliver energy to fuse.  

Jea48,  It is all very confusing.  AFAIK electric current (as motion of electric charge) in wire moves very fast - close to speed of light.   Individual electrons also travel fast at about 1% of the light speed (2000km/s) but they move in different directions.  What moves really slow is average speed of all electrons (drift velocity).  Back to our analogy with balls stacked in the tube - last ball will start moving the same moment as first ball (they push each other).  That's electric charge moving (electric current) at the speed of light.

The "electron drift" IS the electron velocity.

No, it is not.  Electron drift is AVERAGE speed of all electrons.  Individual electrons move fast at about 1% of speed of light even without electric field (Fermi Velocity).

No, actually that analogy intimates that current travels instantaneously, which cannot (rpt cannot) be true.

Line of balls is simplification of lattice of electrons that is disturbed at one end. As I mention before connection between electrons is not a physical one.  Electrons poses electrical charge and repel each other.  It takes time for disturbance of the lattice to travel thru wire.

Thus electrons are charge carriers, they are not the charge per se.

Electrons poses the charge - it is called Elementary Charge.  There are two forces between electrons - gravitational and Coulomb (electrostatic) force.  Gravitational is attractive but is very, very small in comparison to Coulomb repulsive force, that exist exactly because electrons have charge.

Drift velocity is average electron velocity since it is "net" axial velocity in one direction while electrons move in different directions.  

https://en.wikipedia.org/wiki/Drift_velocity

Al, Herman is right - electric current (electricity) is a flow of electric charge.  Current does not flow, current is - charge flows.  The same is true in the river - water flows and current is.  Unfortunately improper usage of "current flows" (instead of electricty flows) is so common, that I found myself using it.  Improper became common.

Al, I mentioned Fermi velocity to show that drift velocity, speed of electrons and speed of electric charge are three different things.

Therefore in this wire the electrons are flowing at the rate of 23 µm/s. At 60 Hz alternating current, this means that within half a cycle the electrons drift less than 0.2 μm. In other words, electrons flowing across the contact point in a switch will never actually leave the switch.

You’re talking AGAIN about electrons. Electric current moves with the speed of electric charge (electric field) and not the speed of electrons or drift velocity. When you flip a switch electric charge moves thru conductor at the speed of light (remember stacked balls?) magnetic wave follows at the same speed. If electric current moves at the drift velocity then in very long cable electrons at the end would not even move since it would take hours or days for charge to get there. All electrons along the wire move together instantly like stacked balls. Electric and magnetic fields have to move with the same speed (electro-magnetic field) because one doesn’t exist without the other. Again, imagine pipe filed with ping-pong balls. When you push them at one side of the pipe they will start coming out at the other instantly. When there is no change (DC) electrons move at drift velocity. DC current is proportional to drift velocity while drift velocity is proportional to magnitude of electric field. Any sudden change at the one end of the wire will travel thru the wire at the speed of light and it will arrive almost instantly and not a few days later. It will travel as wave of electric charge inside of the wire (stacked balls) and wave of magnetic field outside of the wire at the same light speed (or close to it).

Under the influence of an applied voltage/electric field, I believe that ALL electrons do NOT travel axially, in a direction corresponding to the polarity of the applied voltage, just SOME of them do. I believe that some of them continue to move in a random manner, at the Fermi velocity.

Al, Wikipedia definition, I posted before, explains it:

The drift velocity is the average velocity that a particle, such as an electron, attains in a material due to an electric field. It can also be referred to as axial drift velocity. In general, an electron will propagate randomly in a conductor at the Fermi velocity. An applied electric field will give this random motion a small net flow velocity in one direction.