[nana77]

Thanks:

What Is A Conductor?

Electricity is a necessary part of our lives today. It is essentially tiny charged particles called electrons hurtling through conductors from one point to another, carrying current. The current in the wire is dependent on the electrons moving through the conductor.

The speed of the electrons is dependent on whether it’s traveling through a good conductor of electricity or if it’s an insulator. A great conductor allows for electrons to pass through easily and quickly. An insulator blocks the passage of the electrons, limiting the current from flowing. Hence, a good conductor has “low electrical resistivity” and insulators have “high electrical resistivity”.

Gold is used in electronics because it is more inert than copper, meaning it does not corrode as easily. Gold is also ductile and malleable, so it can be easily drawn into wires and hammered into sheets. These properties make gold a reliable choice for electrical segments.

Copper is an excellent conductor of electricity; it is economical and easy to purchase, so it is the most common metal used in wiring. Plastic is an insulator and is often used to encase wires to prevent accidents. The best conductors are often metals like silver, gold, iron, etc.

Copper is a better conductor than gold.

Copper is comparatively not as malleable or ductile, and is, therefore, harder to work with. Another quality of the metal that makes its use favored over copper (or even silver) is its reactivity. Gold is known as a “chemically inactive” element, which means that it doesn’t react with other materials easily. Under normal conditions, it is inert, unlike copper or silver, both of which easily corrode and tarnish.

That being said, there are some scenarios where gold-plated RCA cables might make a tiny difference. For example, if you’re using extremely high-end audio equipment with very sensitive electronics, a high-quality gold-plated RCA cable might help reduce signal loss and degradation. However, for most people, the difference will be imperceptible, and the added cost of gold-plated cables will be a waste of money.

* Smaller signal loss: Gold’s high conductivity reduces signal attenuation, resulting in a more accurate and detailed sound reproduction.
* Better shielding: Gold plating can help to reduce electromagnetic interference (EMI) and radio-frequency interference (RFI), which can degrade the audio signal.

Now, there are differencies and middle ways between being cheap and super high environments.
The massive plug for that Sub link has been made for the specific reason to prevent data losses or interferecies, the gold plated insulates it; that's sound/audio engineering.
If you want to point that I did spend 30$ for that cable, to provide a better, stable sound for a subwoofer on a car (I love her, btw - it's allowed, in english, to say "her" if someone has affection for a machine, a car, spaceships, sailships... etc ).... well.
https://www.scienceabc.com/pure-scie...ectronics.html
https://smallusefultips.com/are-gold...cables-better/

Gold is a ductile and malleable metal, so it can easily be drawn into wires and hammered into sheets. About 28 grams of the metal can be beaten into thin sheets of around 17 square meters

Oxygen-free Copper (OFC), sold in several grades. The various grades are marketed as having better conductivity and durability, but they have no significant benefit in audio applications.

Edit II: pardon, but if

A layer of a suitable barrier metal, usually nickel, is often deposited on the copper substrate before the gold plating. The layer of nickel provides mechanical backing for the gold layer, improving its wear resistance. It also reduces the impact of pores present in the gold layer.

At higher frequencies, the skin effect may cause higher losses due to higher electrical resistance of nickel; a nickel-plated trace can have its useful length shortened three times in the 1 GHz band in comparison with the non-plated one. Selective plating is used, depositing the nickel and gold layers only on areas where it is required and does not cause the detrimental side effects.

If that's true, and if that process has been used on that subwoofer's cable, wouldn't that be an hell of egineering, too? (like, cutting higher frequencies before the amp's low pass filter? LOL!)
https://en.wikipedia.org/wiki/Gold_plating

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The real problem with high capacitance exotic cables (such as ribbon cables, interwoven cables) is that they short the amplifier in a very wide frequency range around the quarter-wave resonance frequency (between 1 MHz and 10 MHz). There is no such problem with zip cords or twisted pairs...

https://www.tonestack.net/articles/c...ble-guide.html

For most low-power home or car speakers (not subwoofers) 18 gauge (18AWG) is fine. 18AWG wire is good for about 50 watts for 4 ohms and 100 watts for 8 ohm loudspeakers up to 50 feet (15 m) or 100 feet (30 m) respectively.

Please don't tell me that cable, which was the default from the car audio stereo, it's fine: https://imgur.com/a/ZAv5PfF
like... 20 AWG?

As long as speaker wire resistance is kept to less than 5 percent of the speaker's impedance, the conductor will be adequate for home use.
[...]
Depending on the hearing ability of the listener, this resistance begins to have an audible effect when the resistance exceeds 5 percent of the speaker's impedance.[4]

A speaker wire's impedance takes into account the wire's resistance, the wire's path, and the dielectric properties of local insulators. The latter two factors also determine the wire's frequency response. The lower the impedance of the speaker, the greater a significance the speaker wire's resistance will have.

Btw, a nice term: Audioholics