strange rel subwoofer cable phenomenon

I've been using a Rel Storm III sub hooked up both ways (sunfire theatre grand II to the rel for .1 and bryston amp to the rel for 2-channel). I've been using a cheap interconnect for the .1 track (Ultralink Subsonix) and decided to give some higher end cables a try. The Cable Company sent me some Synergistic Research interconnects (one at $350 and one at $550). I like the brand and have the Kaleidoscope Phase II DAC-Pre and Pre-Amp after extensive testing. However, in this application I literally could not hear a difference between any of the 3. I heard only a tiny degradation when I tried the thin plastic cables that come with most popular-brand equipment. Is there something wrong with my ears or is this sub cable-proof? Anyone else out there found this to be true? I've been told that both XLO and Synergistic make neutrik connectors that will make a huge difference for the Rel, but now I'm not so sure...
Not to worry. In objective tests most people cannot tell the difference. You're being objective, you're listening. So much (incorrect) hype and BS about wire. Save your money and enjoy.
I don't think it much matters if you can't hear the difference. Isn't that the ultimate test? I trust your judgement more than my experience- after all, your ears are in the room. One caveat- don't listen to those who say cables don't matter. They do. Luckily my wife has great ears and can hear the difference too. When I upgraded to Siltech she heard a big difference. The previous upgrade to Synergistic Research had been a big disappointment. A lot has to do with your gear. One nice thing about Audiogon, is that you can try a lot of things cheaply.
I bought a cheap cable from Best Buy for my Stadium IIIs and replaced my Cardas Hexlink with it. I didn't hear any difference in the sub. Sold the Hexlink and pocketed the difference. On the other hand, I went from Cardas NR to Nirvana X-S between my preamp and amps and noticed a large difference.
Oh yeah- I meant the cable upgrade from cd to pre-amp and pre-amp to amp made a difference ( I upgrade both pairs at once). My speakers have a built in sub, so I don't use one.
I have replaced my Rel Neutrik cable with Signal Neutrik Cables and found out that the Rel is sounding much deeper. Try them. There is money back gurantee.