Although overlooked by most, this forms an extremely important component of your job.
Speaker Wires: When you a buy a decent pair of speakers with some cable inside, it is perfectly fine to use these in case you have no amplifier.
However, the minute an amplifier is in the equation, it is time to chuck those in-the-box cables and go for better speaker cables.
For components, Speakers etc, I recommend a good OFC (Oxygen free Copper) speaker wire that should be 16 or 18 gauge. It is not necessary or recommended to go for overly thick cables in this case, as it may actually prove detrimental to the higher frequencies.
For the Subwoofer I would definitely recommend 10 or 12 gauge speaker cable. I also find that taping up your speaker wires in PVC tape (I am referring to a WRAPPING tape, available at auto stores, this is not glued) provides stability, protection and ease of installation. Do not use twisted electrical cable etc.
In case you need to have a removable joint - especially in the case of a boxed/tube subwoofer, (In case you need to go to the airport, or to fold up the seats, lay out a clean mattress, fresh smelling sheets, 2 glasses and a bucket of ice for the Champagne so you can make out madly in the rear of the car which is parked somewhere in the hills…. So… where was I? haaan..), please use either an XLR male female connecter, ot a SPEAKON male female combo. If you leave bare wire hanging around, it may touch each other, blowing up your amplifier in the process.
While attaching the speaker wire to the speaker, either use crimped spade connectors or solder the wire directly to the speakers.
Extremely important and quite easy to do. 3 wires for the amplifier, a thick one running to the battery terminal, one more of equal thickness running to the chassis of the car and a thin one (any gauge will do) running from the remote on terminal of the HU to the amplifier.
A recommended alternative to using a cheap Chinese wiring kit is to buy automotive wire. Though automotive wire does not follow the AWG concept. This means that if you go upto your auto parts guy and ask for 4 gauge wire, in all likelihood, he will not understand.
You can however ask for certain numbers like 65/24 etc. The numbers are based on the number of strands and their individual gauges. Or in sqmm, I will be able to elaborate tomorrow with precision, on the finolex sizes available.. There are some excellent wires made in India, Finolex is one of them I can recommend.
You can buy 7 meters of the thickest variety and 5 metres of the thinnest. I find that this will suffice most common 2 and 4 channel amplifiers below 100W per channel.
If you have 2 amplifiers, I just recommend doing this twice over.
In cases of higher powered amplifier and multiple amplification, I recommend using imported original power cables, possibly distribution blocks, inline fuses etc.
Remember, do not run these power cables on the same side of the car as the Audio cables.
RCA Patch cabling:
Basically the wires that carry sound from your HU to your amplifier. Can change the tonality of your system, BUT remember, you need to have good quality amplifiers and speakers to appreciate this tonality.
Allow me to explain. I personally don’t use car audio RCA cables, I prefer to make my own, using high grade audiophile wire, from companies like Van Den Hul or transparent and solder them to Neutrik RCA pins using wonder solder. I experiment with carbom based, silver based and many various wires. I can do this because I have sensitive ears and I use good equipment. I am from the industry so I do not perceive these things with the same monetary value as most of you do. What’s my point?
Even a half decent system needs a good pair of RCA patch cabling. Avoid the Chinese kits. Instead I find that a good 5 metre RCA cable from MX (an Indian company, commonly available) has better performance than a Chinese unbranded RCA cable. Of course if you can afford a 5 metre cable from AR, Connection, Monster etc there’s quite nothing like it. Watch out for fake Monster though.
You can safely run your RCA cabling along with the speaker cabling. Remember to keep them away from the power cables. I wrap these too. Navin and a few audiophiles sometimes wrap these in tin foil (yes the cooking kind) and earth the foil. This will debatably protect your audio signal from external interferences.
I hope this was useful, more tomorrow.