Gauge + Length +Material = Sound

Any length change of cables will change the sound.Without trying it,who knows how much,and how noticeable.

My prediction is Wishful thinking + Expectations = Perceived Change in Sound.

There is no likely change in sound for short runs of RCA for several feet when using properly matched, well designed and well functioning equipment.

Since you do not hear a difference your equipment is probably good.

Although you might begin to hear something if you went more than 20 feet of RCA on some gear (due to capacitance) and very likely you would hear an audible difference with 100 feet of RCA.

There are volume, as well as bass and treble tone controls on most gear and you can always buy an equalizer - these are all well suited for modifying the sound. Trying to modify the sound quality through changes in cables is very much on the border of and generally well below what is audible unless you go to extremes (from a science/equation perspective).

hahah lol - good point!

To hear minute nuanes that can be imposed by interconnects requires highly resolving systems. Also, length is not a factor for most of these nuances. Materials, and how they are used, and interact with one another will be the mitigators of change. If you want to exeriment with this, change the configuration of the cables COMPLETELY. Use different connectors, with different metal compositions. Use a different gauge OR combine two together (winding is tricky though). Use different conductor metals. Whatever your do, if you want to try to eliminate any variables, keep it consistent. Shielding will make a difference, dielectric composition will effect signature vs. time. These will not be big differences, but could "steer" your sound a few degrees one way or another. Again, it depends on your equipment's ability to provide black background, and high resolution.