connect 2 different wire gauge to pos and neg speaker terminal

@chalmersiv - although you will still hear music the sound quality between the two different combinations you mention may be different

If you step up to a higher quality ground wire then the quality will not be impacted

I currently use a high quality 16 gauge silver plated Mil-spec wire for the signal and a reasonable quality 13 gauge (2 x 16 gauge) for the neutral. The sound is extremely good, but that is due in large part to the geometry of the cable rather than the quality of the conductors used.

See:
http://image99.net/blog/files/d048bbacfce9bcad4a025be804771d9a-76.html

I have experimented with different combinations of conductor and having a thicker gauge neutral seems to provide a better sounding cable.

Although it would be nice to get away with cable from Lowes, there is no substitute for a conductor made from a reasonably high quality copper

I have also experimented with Romex, 12 gauge Extension cord (from Home Depot), Kimber Kable and the wire in the link above, using various geometries. The cables in the link above provides the best sound quality to date, surpassing all of the various store bought cables I have tried to date

Hope that helps - Steve

Good comments by Steve (Williewonka). I would add that if the + and - conductors referred to in the OP are not in close proximity, and preferably twisted together in some manner, the inductance of the cable will be considerably increased. If the impedance of the speakers is low at high frequencies (as it is, for example, in the case of many electrostatics), and/or if the cable length is long (inductance is proportional to length, for a given cable type), that may result in perceptible rolloff of the upper treble, and dull or sluggish sounding transients.

Also, in terms of wire quality I would consider the negative conductor to be no less important than the positive conductor. After all, they are conducting the same current, just in opposite directions at any given instant. A conceivable exception to that, however, is that the amplifier might be more susceptible to RFI/EMI picked up by the cable and introduced into its feedback loop (if it has one) from the positive conductor than from the negative conductor.

Regards,
-- Al

@almarg - you raise a point that has puzzled me for a very long time

  After all, they are conducting the same current, just in opposite directions at any given instant

Granted, the current may be flowing in the opposite direction in the signal conductor, but can the same be said of the neutral?

Is the neutral actually the opposite of of the signal?

When you consider - the neutral conductor in IC's are actually connected to the -ve side of the circuit(s) in the connected components and it's only the signal conductor actually "carrying" the alternating signal, things start to look a little different from the "return path" approach most people are familiar with.

 Granted - you do have to have to connect both  signal and neutral to both components to "complete the circuit", but is the neutral actually transferring energy that reflects the signal, i.e. except for its opposite polarity?

All of my cables now use different quality conductors, mainly because I have tried using the same conductor for signal and neutral  and found it provided no discernible advantage.

Having said that the quality of the neutral conductor I use is quite high

EXAMPLE: in my IC's I use a solid silver signal conductor and a quality copper neutral conductor of approximately twice the gauge of the silver.

Using a copper signal & copper neutral results in a less dynamic sound than the Silver Signal - copper neutral IC,
But using a silver neutral with a silver signal provided no benefit over the silver signal and copper neutral IC.


Also, when I think about speaker cables, the "energy" in the signal conductor must be very different from the neutral side simply because by the time the signal gets through the speaker voice coil, most of it has been converted into the movement of the driver, so the neutral must be quite different - doesn't it?

As I said - it has perplexed me for a very long time - even more so since I experimented with cables and experienced my observations.

Any help understanding this would be appreciated

Cheers - Steve