It seems that all headphones have inherent peaky treble response, some of which is by design. Check the graphs. There is almost always a big dip between 3k and 5k accompanied by a few more dips and peaks and then a sharp rise in the 9k 10k region. I do my best to obtain a flat response using tones sweeps and different music. When I A B the non equalized to equalized a light comes on and I say to myself, oh that's where the music was hiding!