Monitor 60 problem

ajaxmt10

Hi all! I am new to this so I apologize in advance. I just got a pair of 60's that I have biamped as my mains. I have only had them about a week or so. The other day I was listen to some songs and I noticed something. The trebble on the right seems off. With some songs it sounds scratchy but only with certin frequencies. Most of the time it sounds awesome but sometimes I will get very unpleasent scratchy highs! I have turned down treble and that helped a little but I can still hear that somethings not right from time to time. Any and all help would be great. I am using an ONKYO 805 with new speaker wire and banana clips.

Have a good holiday all!