Gerry Lemay：I think it’s important to point out that it's not whether or not cables can change the sound of your system or even if you can measure it, but rather the utility and value of such changes. For example, adding resistance to a piece of wire changes the load on the amplifier; is this audible or measurable? It depends on the amp. It's not unreasonable to assume that this change will be both somewhat audible and measurable, but is it beneficial? Its doubtless that one of the characteristics of proper speaker cable is low resistance so the power of the amp does, actually, drive the speaker and not heat up the cable. I won't restate the many discussions that have been made about the audibility of expensive cables or changing other electrical characteristics such as capacitance or inductance; I'll post a couple of interesting links here.
Playing with any or all of the electrical characteristics of interconnects and speaker cables can change the sound but it's no different than using an RC or RL circuit to change the frequency response of the system. That's pretty much what old-fashioned analogue tone controls did. For audiophiles who relish direct circuits without tone controls, adding a "bright" or "dull" sounding cable may be the only way to "tune" the system's interaction with a conversely "bright" or "dull" sounding speaker, but that's not going to preserve the accuracy of the signal or contribute to the clarity or detail of reproduction. Today we have digital signal processing (DSP) that allows us to not only adjust the target frequency response of the system but also correct acoustical problems that are far more audible than any very minor changes caused by various cables. These DSP units minimize any distortion and do not contribute to phase distortion. In fact, it has been shown that correcting the systems frequency response actually corrects the phase response.
I always recommend keeping the load on the amplifier manageable by using the proper gauge stranded wire for speaker cable and choosing high quality interconnects that are flexible and durable. And yes, gold connectors are a good thing to minimize corrosion at connection points (and even that can have problems with corrosion if not properly attached).
I think it's worthwhile buying high quality cables, but not to add some non-quantifiable element of quality to the sound, but rather to allow the system to perform reliably and at it's proper specifications.
Gerry Lemay：I am interpreting your question to be understanding the sloping of the high frequency (HF) response at various distances from the speaker. The near field is usually defined as within 1 meter of the speaker; here we will see no sloping of the HF response. A measurement at this distance is often considered similar to the anechoic (no acoustical distortion) response. This distance is most often used in recording studios and some would argue many audiophile systems are close enough to be mainly a near field signal. It's important to understand that this non-sloped or flat response is considered to have too much HF and thus is not the best. Speakers placed this close to the listener should be equalized (EQ) to have a sloped response to sound correct. This is usually already accomplished in the cross-over of near field studio monitors, but it can be adjusted by a slight adjustment of a treble tone control for other speakers.
In small room acoustics, we rarely discuss the middle field. The reason is that the defining distance for the far field, the critical distance, is usually in front of any listeners in a proper listening room. The key to understanding the best sloping is matching the frequency response of your system to the frequency response of the recording or mastering studio where the recording was mixed. For most high quality movie studios, the dubbing stage has a strongly sloped HF response. For most music studios, there is a much lesser but still sloped response. The difference is due to the size of the mastering room; large rooms are calibrated to have strong sloping and small rooms use much less sloping. In our home theater or listening room we generally desire a less sloped HF response but certainly not a flat response. It is the calibrator who can determine this but, again, a consumer can simply adjust the treble control to their preferred sound. I have attached a picture of a "flat" near field measurement versus a preferred "sloped" listening position measurement to help clarify my comments.
I should add that movie sound tracks are often not re-mastered for home theater use although more and more are. An untouched movie sound track is usually considered too bright (not enough HF sloping) because it was designed to sound good in a large theater with a much more sloped HF response. Most home AVRs offer a compensation control designed for such sound tracks but it must be manually turned on. An acceptable alternative is to again use the treble control to adjust the sound to the users preference.