DJM900 Pan Issue

Hi all.

The output level indicators on my mixer are not at equal levels when they should be, the left is always about 3db higher than the right, this is also experienced in actual audio output.  Setting the pan pot to about 2 o'clock seems to even it out.

This happens on every channel, am using the digital ins, will check the analogue tonight.  I have 2x CDJ2000NXS and experience the same with each so I am convinced it is not the players.

Any idea what may have caused this?  Any other info you would like?  I had noticed it before but dismissed it, now I have upgraded my speakers and positioned them properly I am certain there is something not right.