What speaker cable made a major difference in the sound quality of your speakers??


I am curious what speaker cables made a big "jaw dropping difference" in the sound quality of your current speakers.  What most impressed you about the difference;  that is, overall musicality, tighter, deeper bass, midrange clarity and soundstage depth, etc.etc. 

Keep the price of the speaker cables chosen or auditioned at  between $800- $1000 or  from  $1000-$1500. Was the cable bought new or used??

  Thank you,   SJ

sunnyjim
Tellurium Q Ultra Black speaker cables and jumpers ,the impact was huge took my system to a completely differnt leauge. 
Perfectpathtech - thanks. I was leaning heavily towards Rio grande anyway, so thanks for pushing me the rest of the way..

Imma order the wire this week, I think.
A bit outside the parameters you layed out regarding price points. But for me so far it's been nordost. .just finished doing a demo of TYR 2 power and speaker cables..didn't realize how much of the music I've been missing.has me curious to hear Valhalla or odin. 
Ok, I have to follow up on my original post. I have now installed the Morrow SP-7’s and I have no idea what the other poster was saying about them sounding "phasey". Each system is different however and in my system the SP-7’s are a clear jump in sound quality as compared to the SP-5’s they replaced. What is better? Everything, they are a much more engaging cable than the SP-5’s. My tastes run from rock to jazz and world music and I must admit, these new cables are sweet! I was listening to Neil Young, Live at Massey Hall the other night while my wife was cooking dinner and even she commented that the music sounded great. Of course, she had no idea I had switched out the cables. This is my experience, your results may vary!