There is some really cool stuff that you get when you use an a/d converter in conjunction with a soundbar. First of all, when you plug in the piano, the soundbar will automatically turn on and switch to the right input. In this case the input is be "Optical."  The other advantage is that the optical connection is nice and solid.
AirPort Express mounted under piano with white bracket.
White Signal Cable for easy identification.
WiFi signal to from PD Remote app on your iPad to AirPort Express under your piano.
IQ Control Box Under Piano