Just near the end of the break-in period on my Sapphire M3s, I decided to try a pair of AntiCables Level 3.1 speaker cables. The improvement was shocking. As others have said, the M3s (and siblings) will reveal and reproduce every subtle difference in what is feeding them.
The difference with the AntiCables, however, was not subtle at all. Bass gained texture, midrange clarity was astonishingly better, harmonics became more natural, the air and openness improved, harshness in the very high frequencies disappeared, and very deep bass appeared where it wasn’t coming through before.
The improvement has been so profound that I’m considering their Level 5 cables at 10x the price. I have ordered one pair of their Level 4.3 XLR interconnects to see if that makes a difference.
Considering the cost, Spatial Audio should bundle a pair of AntiCables Level 3.1 speaker cables with each set of speakers. It’s probably impractical, but I wish I had realized sooner how massive the difference would be using the AntiCables with the Sapphires.