What cables can lower my forward treble.

no cable has that ability in my experience with cables. Also why do people always list these things and not list the speaker that is clearly producing the supposed forward treble

Dali Euphonia 

MS 4

How big is your room? Is your room treated acoustically? What distance are you from your speakers? Are your speakers toed in?  These may all be factors. 

Different cables might help a little, but they’re generally more of a fine tuning.  

Ever considered adding felt to the front baffle to reduce reflection and diffractions?  Spica, Vandersteen, and others have done similar.  1/2" wool ironing or crafting felt is pretty cheap and effective.  I cut it into small triangles and made a starburst pattern around the tweeter, but you can arrange it however you want until it suits you.  Easy to adjust and undo too. 

Felt