Hello VintageGenX thanks for the response. The adaptors are hand made 1.5 meter cables by FMS & not those small balance to unbalanced adaptors. I consider anything an adaptor that changes from one thing to another within it self. I have tried differant adaptors small ones and ones they use in band equipment and it doesn't make a differance. I have them because my old VAC amp and preamp. They had only RCA connections for the front L&R speakers so I had them made all the same just the legths are differant . I did not have that 6 bd issue with the center speaker at that time and that is why this bothers me cause that part has not changed yet the calabration db has.

Norton
G68AXV