Frankpiet, in my system, I first replaced my interconnects one cable at a time (from Kimber 1030 to Jena Labs Symphony) then, subsequently, replaced my speaker cables (from Transparent Ultra XL BiCables to Jena Labs Symphony). While there were gradual improvements in sound quality throughout this period as each new Jena Labs cable was installed, I personally think that the improvement was primarily due to the Jena Labs cables simply outperforming the predecessor cables as opposed to some pervasive synergy issue. It's hard to say, though, since I only have this one experience with my system by which to judge.