Can someone give me some insight.

This is sort of annoying and I need some help here.I have been auditioning different interconnects.MIT,Nordost,Synergistic Research to name a few.I thought I had a winner with Synergistic but what I am finding is when listening I am loosing volume in lead guitars and lead vocals.I have some Monster interconnects that I am trying to replace.If I just use the Monster IC's the voices and lead guitar is strong and open but there is lack of clarity..When I use any of the above mentioned IC's the lead voice and guitar are toned down a few db's and now seem more in the background.
I will admit that with the above mentioned higher end IC's everything is so much nicer.Are the Monster IC's over blowing the top end.I do not understand why this happens.
Last night I had the Nordost Red Dawns from pre to amp and was listing to and watching Roger Waters in the flesh-live.All sounded really good except Roger Waters voice was subdued and when it came time for some lead guitar it was also subdued and more in the background.This was being feed to my pre by hdmi and bitstream.I then changed to Synergistic IC and it was the same.Then the MIT and still the same.Then the Monster and the lead guitar and vocals returned to being upfront and in your face.
Since all the above higher end IC's exhibit this toning down the vocals and lead guitar I am starting to wonder if that is the way it is supposed to be.This also occurs when listening to cd's via analog direct or digital.
My system is Rotel 1069 pre.Rotel 1075 amp,Rotel 1072 cdp and B&W 683 speakers and bluray ps3.
Any thoughts on this would really help me out as I do like a lot of the IC's I have auditioned.Thanks.