No IPOD sound from Kenwood DXN525!

[Tcorf72]

Hi all! I need some help... I upgraded my stereo to the Kenwood DXN525, easy install and everything works great except I can't get any sound out of the IPOD when connected through the HDMI Aux in. The IPOD is definitely connected, all the info is up on the screen, even the dash, and I can see it playing but no sound. All other inputs work fine and sound great and I have been through the menus and set up guide and can't find anything relevant. I have tried different IPODs too and now I'm out of ideas! Any advice much appreciated...