Will increasing speaker cable AWG make a difference in sound quality?

If you’re running the recommended size and go to a much larger size, I would say no. If you’re running some thing that’s way too small and then you go to what’s recommend it then you might.

@ghdprentice kinda said it all IMO without much further need….. ( quality build matters , not just bulk. Think important contributing and bespoke factors such as dialectic, Litz design, et al)

The only thing I can offer for you ponder as you navelgaze the lint in your navel , is a published opinion post on why “beefier” build speaker cables can indeed matter.

I wouldn’t bow to it as irrevocable gospel for all systems, simply because there are good reasons why exhibitors choose the “flat and thin” NORDOST VALHALLA / ODIN cables as one of the two major leader cable choices at the audio expos,.along with the “beefier” CARDAS CLEAR / CLEAR BEYOND models.( Note: you will never see cheap budget cables there for intuitive reasons …’nuff said)

I upgraded from NORDOST FREY to CARDAS CLEAR with improvements that were not subtle in MY system…( emphasis added );…surely others may have differing outcomes.

MT TAKE: it only reveals itself by hands on experimentation. From personal,experience, simply upgrading to a thicker gauge in like budget build / budget performance cables likely won’t get you much.

SPEAKER CABLES - From Alan Shaw (owner and designer of HARBETH)

” … So, the moral of the story is this: the most important factor of the loudspeaker cable that you should select is the amount of metal in the cable core. More metal means lower resistance.

If the core is round (as most are) then the correlation is simple: the fatter the diameter of the metal core the better because the electrical resistance between amp and speakerwill be lower.

Thin and really thin cores should be avoided regardless of how exotic the metal material is claimed as the lack of metal in the core conductor will increase resistance. That will reduce amplifier damping, effect the frequency response of the speaker and give unpredictable results that will vary from amp/speaker combination.

Do not be fooled by the diameter of the external plastic sheath: what matters is the metal content of the core. The more the better, without exception….”

In general you’d expect moving up within a company’s product line should yield improvements, especially if in addition to gauge you get other improvements in things like quality of the conductors, geometry, connectors, dielectric, etc.  So there are several variables at play here in addition to the gauge of the cable. 

As indicated by the Alan Shaw quote, the main factor affecting the performance of a speaker cable is the aggregate area of the conductors…to a point - as discussed by @raysmtb1.  IOW, if you have enough, then more will probably not change anything.   How big you need is affected by the current you are driving, based on the efficiency of your speakers and the output of your amplifiers.

However, the other cable materials and construction factors can also make a sonic difference.  As an example, my go-to choices here are both bi-wired cables, a stranded copper cable with two runs of 7awg to each speaker and the other being two 9 awg runs of a multi-strand, individually insulated, solid core copper cable.  I can tell the difference between them but I like them both and probably 4 times out of 5, I prefer the smaller, multi-strand, solid core cable.

if you are pushing a lot of watts, 15awg could be small’ish.  However, as others pointed out, you can go larger without breaking the bank.

Regardless of the quality of the copper, its treatments and the insulation used, and without considering capacitance and inductance, which is the speaker cable on the market with a larger copper section, therefore with less resistance for the same length?
(the final separation and possible reduction of a few cm to be able to enter the forks or bananas does not count)