Speaker Cables

it is of course system dependent as well as dependent on listener tastes, but having said that proacs (and d30r's specifically, which i have) tend to highlight the treble and lean out the midbass a bit, so best to use all copper cables that provide some warmth... no silver/silver plating...

tuneful cables of brooklyn makes very affordable cables using belden 9497 copper with excellent terminations... it would be a very cost effective very good sounding place to start... not to say others won't work well

Speaker cables make a difference. And I have had success with Canare 4s11 internal biwire - I preferred them to audioquest rocket 44. 
I encourage testing because I thought it was ‘a myth’ until I tried it. 

I’m going thru the same thing as the OP. For the longest time I’ve used a great set of 10 GA stranded silver cables connected to the bass inputs per JBLs preference, with some jumpers.

After a while I tried going to the upper set but it sounded worse. Going from one upper to the opposing lower sounded better so it got me thinking of true bi wiring.

The only similar cables I had around are a 14 GA and 16 GA set of Tempo Electric solid silver cables with bare ends. The 16 GA was easily the best. By far, the best sounding system to date. But then, I read Vanderstein’s take on bi wiring and how both cables should be of the same gauge and length, lest other anomalies present themselves.

With my system being on the edge of some brightness but with tons of detail and liveliness that I crave, I noticed how using two cables brought out even more musical details so maybe it’s time for some great quality copper cables.

So now it’s back to the drawing board. The more I investigated, I came across Audioquest and their Rocket series. There are two separate, insulated runs of 4 solid copper wires joined side by side that make it a great choice for an internal biwire and Audio Advisor offers a large discount if you buy the plain version of them if you allow them to terminate and finish the cable instead of buying the finished product. It’s almost 1/3 off. I just might go for a pair of Rocket 44s, but I’m still researching.

All the best,
Nonoise

@mastering92 The cable itself should not have any sound characteristics.

When you talk about "cable synergy" in a system, that does not exist.

If I were you I would test 2 pairs - 1 cheap and well built cable, and a more expensive cable for your choice. You should be listening for transparency. Does any octave sound elevated after a cable swap?

Mogami, Canare, and Belden are the typical standard for Pros.

If you can tell a difference and one cable sounds better, that's fine.

@mastering92 
What cables have you actually tested yourself, and with what amplifiers and speakers? Can you describe the listening results for each test case?

I also have had no issues with my Canare star quad cables running in biwire mode on my trusty Epos M22 floorstanders.  The Epos tweeters can sometimes play sharply, but the Canares keep that well under control but also allow excellent resolving detail to come through in my system.  I haven't tried super expensive cables as I always feel that kind of money is better spent on better equipment.