Which cables go with what?????

Throw the theory and other things aside,
I totally agree with Ridgestreetaudio and Audioengr.

If the cable is well designed, it should perform well in all systems. A good cable should enhance what you already have. i.e. A better cable can bring you more detail and image without changing the tone. IMHO, that would be the ideal "neutral" cable - a cable that is capable of producing same volume at all frequencies passing from the source.

However, some cables do add more than just clean sound to the music. i.e. If a system is too bright ( I see a lot of comments here on audiogon ) then listeners would look for some "tone down" cable. If a system is not enough bass, the listener would look for a cable to add "punch and volume" in the bass. The cables they're looking for is not neutral but just to help the system match issue.

Being able to make DIY cable myself, I'm now have a better understanding of finding the right combination for a bright system, neutral system and dark system. The cable for neutral system will work any the well matched system.
If I walk into a hi-fi store, I'll definitely bring my own "neutral" cable as the reference point.

All these are my opinion based on my own experiment and experience. Your results will vary according to your listening conditions.

Ridgestreetaudio's way of making the "neutral" is based on data you collected and not based on physical property of the cable you make. This is a good approach and I've done the same myself to determine what's "neutral" to me. What you're doing is helping your clients learn how to match their system (As I mentioned in my previous post.) On behave of your clients I would thank you for your effort(I actually never audition your cable before) of making everyone enjoy their system. This is exactly what Sean said:

"If both systems are deemed to be "accurate" and / or "musical", etc..., then it really doesn't matter HOW we got there. The end result is the same, we just took different paths."

In another words, a cable doesn't have to be neutral as long as the system is neutral.
This is the my first thought when I became an audiophile and it is still my strong believe. Regardless of what speaker, amps, preamps, and cables you have, as long as the source is the same then the output should be the same with slight difference is detail and presentation.
i.e. A violin should sound like violin but detail and imaging can vary. However, many folks disagree with me because they believe in component dependent rather than end result.

leme@lone.com, if you can build it they'll buy
: )

Nrchy/Sonic_genius/Nighthawk: FIY, cable business is very hard to make a buck because lack of customers. Audio is a luxury hobby not neccessity. Many of them has a real job other than this hobby. However, they're very proud of what they design(or something they found) and they're trying to prove that their idea works.
exactly like Corona said
If you don't read this why you come?
and obviously there are some hidden secrets where you need to find out yourself otherwise they wouldn't be able to stay in business.

Sean is correct, I don't have equipment to test any of the DIY cables I built myself since I'm not in EE or a real hifi shop. I only work with a 99 cents plier, a radio shack twizzer and solder iron and a good set of ears : )
Btw, I did have ME degree more than a decade ago but I've never work in the ME field. I'm currently in CS field.

Here are some hints:
I have found that solid core gauge size has more sonic signature (based on the resonance frequency response) and insulation (vibration damping) and shielding (dielectric)has more influence in noise reduction. The electrical property (resistance and capacitance) will have greater influence on pace and rhythem (pace). The purity of the material (metallurgy) will increase the detail over all.

The statement above is based my own findings from DIY IC and speaker cables. I have not applied the above on AC cords yet.

For all the DIY folks, you can try to build the most suitable cable with above conclusion in mind and you'll be happy with the results or you should have a good idea of what type of cable you own and what needs to improve.