Optimise concert piano sound of px 760

[Robbie]

Hi just bought a privia px 760 second hand but in mint condition. I trusted the reviews talking about an award winning piano sound. 

I must say I am far from impressed. Particularly C3 to C4 sounds too bright and metallic to the point that my 8yo daughter asked "is that a guitar?" 

I reset everything to factory default, but that sound is still there. 

Any tip on how to optimise the concert piano sound to make it sound like a ... piano? 

Thanks