This question is often turned into nonsense. The technology is really pretty simple to grasp. If we start with your CD player that has RCA plugs and wire connections we find smaller gauge wires than for speakers. Quality wire is more important than size because there is 'no resistance' from your amplifier. A signal is sent a few short feet and the receptical welcomes and all but sucks the signal into the amp. The speaker wires are leaving the amp and when they cover the distance resistance from the wire itself, it hits the drivers which are all about 'resistance'. This is where we turn up the amps and the watts to push the signal into drivers and power the drivers. This is where I use 10 and 12 gauge speaker wire to transport the full signal and without inhibition that small wires would cause. Turn up the volume and a 22 gauge wire will fill up and back up and not be able to transport the full signal or to provide the power to drive the speakers. Remember to think of speakers as 'motors' that require fuel to run.
Hint: I build my own speakers and I also use the large speaker wires internal to the speaker to carry the signal. Open up the common commercial speakers and you will find the tiny wires are most common inside the box. Now a 10 gauge running full out comes to the connection with a tiny internal wire. The little wire crams the force into this inadequate receptical. Big wires on the speaker cables will give you the best and fullest signal. I have used a 22 gauge solid wire of 999.99% pure silver for a tweeter and that can be pretty sweet, but a tweeter rarely calls for more signal because it is only about 10% of total speaker output and a 12" woofer would thrive with a full wire to feed it the 'sounds'.
In short, big wires carry more signal (watts,etx.) to your speakers and mids, woofers and subwoofers perform much better with a large feed wire.
