Ahh, the forbidden and much-maligned arguments regarding wires.
Ok let's start here: wires do make a difference. In a system of high enough resolution, you can hear the differences in wires of all types, from interconnects to speaker wires.
In order of hearing the differences in their "sound signatures:"
1. Digital cables of all types - not much to hear here except for the data gaps from restricted bandwidth/speed.
2. Optical cables ( Toslink) - Ok I'll admit some differences between them but pale in comparison to the flawed concept of taking a perfectly good digital signal, converting it into an optical format then re-converting it back to digital. By the way, that's my beef with the CD format, but that is for another blog post.
3. RCA etc. interconnects (low voltage) - There are clear differences to be heard here. The wire diameter, shielding, and especially the dielectric (insulation) make large differences at even these low voltages of say on average 4 volts maximum. Why do these aforementioned construction factors affect sound? Firstly wire thickness affects resistance that may or may not impede electrical signal transmission. Combined with wire capacitance and inductance of the wire it can form a type of filter which as we know alters frequency response. Thinner wire is better however to a degree. Keep in mind that long runs of interconnects need thicker wire. I'll address dielectric and wire strands in a moment.
4. Speaker wires - the large gorilla in the room. Yes, big differences here. Here is where the rubber meets the road. The last wires in the chain are the most relevant (or are they?). Actually, the speaker crossover coils are the last meaningful wires (excluding the driver's voice coil) between the amplifier and speakers. Larger gorilla-sized wires (here we go again) are not needed at sub-100 volt voltages. It's simply overkill and at worst destructive to your speaker's sound. Large wires require large amounts of dielectric and it's quite difficult for very small signals to bully through all that copper. Fat tires on racing bikes don't cut it for speed, right? When the diameter of the conducting wire increases the skin effect will increase drastically. Skin effect: promotes changes in a cable's electrical characteristics such as resistance and inductance. These change continuously depending on the distance from the surface of the wire. If the conductor cable is too large, the skin effect will also affect the reproduced audio frequencies. Important high-frequency audio will be flattened with treble loss and obscured detail retrieval.
Dielectric of wires - all wires - here is the largest influence on wire audio: the insulation. I say wire audio here as this mostly applies to the ow signals that travel through audio wires. Insulation as we all know needs to be there or wires touch, they short out and no audio at best, and blown components occur in the worst scenarios. The dialectic effect is the phenomenon of materials that absorb electrical signals especially those of alternating current such as audio. In short, we do not want our audio signals absorbed and then released back into the audio stream. That creates timing issues and smears the sound.
The best dielectrics for wire are air 1. o, Kynar®6.4, Nylon4.0, enamel 3.2, Polyester 2.80, Polyethylene 2.30, Polypropylene 2.24, Silicone Rubber 2.6, Polyvinyl Chloride 2.7, Teflon® 2.15.
Lower is better.
Keep in mind here that the dielectric thickness is a factor as well. We prefer enamel insulation. Why? It's the thinness that matters. Enameled magnet wire has a very thin insulation and thusly a low net dielectric constant.
Oh and lastly, that crossover coil in your speaker - a 1 mH / 16 gauge crossover coil has over 75 feet of magnet wire in it....