djm 900 nexus loses frequency

Do you know it's definitely lower than it should be?  The Pioneer DJMs max out at about 5dB down below full scale.  That's nearly half the volume of something like Denon, Tascam, or P P D.

what i mean is that when i raise the volume of the other channel it gets low. it gets low when i do a transition 

Do a video of what you're talking about and post it on youtube.