CONNECTING DECKS TO X30D

[stustu1000]

Hi People

I wonder if anyone can help with this, 

We are trying to connect a set of decks and mixer up to my x30d - it all connects and sounds awesome but the latency on the headphones through the mixer is making it impossible to mix records through the headphones. HAs anyone ever had similar issues ?

Thanks

[HannahEd01]

Hi stustu1000, what are the devices models? The map of connection?