What speaker cables mate well with the Polk LSi 9?

I have a pair of Polk LSi9 speakers that are powered by a Proceed AMP2. I am currently using original (Yes, I said original) Monster Cable that is about 20 years old. For some reason, this cable has bested Nordost's Red Dawn and Luminous Audio's Synchresta Signature. Perhaps the Polk is internally wired with Monster?

I am completely happy with these speakers having previously owned B&W Matrix 805s and PSB T65s. I'm not looking to change speakers. Rahter, I'd like to get the most performance possible from the Polks.

The Luminous produced the most realistic bass I have ever heard, but was its tonal balance was rather warm. Perhaps I didn't give the Luminous long enough to break in.

Any suggestions from folks that have the same speakers but use different speakers cable and are happy with their pairing?
I currently use Analysis Plus silver ovals on my LSi15's and love the results. One thing I'd recommend doing is removing the brass jumpers that come with the speakers and either biwire the speakers or replacing the jumpers with high quality ones(I got some analysis plus ones too). I'm really happy with the results.
I've used a few different speaker cables in conjunction with my LSi9's. I found the Kimber 8TC to offer lower bass response but was kinda rough around the edges. I've since switched to Audience Maestro and found them to be a big step up. A haze has lifted, vocals and higher frequencies seem to have more air around them and pushed me closer to the front row. The bass wasn't quite as profound, but since snagging a Krell intergrated Bass really hasn't been a problem with these speakers. Good luck.
Thanks for the suggestion.