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


The opposite ROI argument can be made about the interconnects as they are enabling the transmission of the lowest level, most "delicate" signal.  If that signal is messed up the best speaker cables extant can't restore what is no longer there.🤔
Yes, there is opportunity to preserve the sound quality and integrity along the path from source to amplifier. That said, the greatest opportunity is on the trip from the amplifier to the loudspeakers, simply on a power loss level. With low level signals, especially that of a moving coil phono cartridge, the greatest ROI occurs at a relatively lower end of the price spectrum. 
I am a cable manufacturer (Bionic Cables) so I will tell you other brands that made jaw dropping differences in the past but system matching is still important.
FMS, High Fidelity, Mapleshade, and Mosaic.

Some cables made huge differences but not in a good way. lol
@max53 I totally agree with you about vertere - I needed a cheaper interconnect than the lavardin ones - recommended these from John at midland audio exchange for £160 - better than the lavardin -