Regarding the sound of the Audya (you mention the Piano sound being tinny) I cant stress enough that all Audya owners should be using a PA with a full and balanced frequency range. Almost all budget PA systems on the market are missing mid range. (and by budget I mean under £2000)
The problem is every PA owner will insist their PA is fine, but if you want to experience your Audya at its best you need an almost Studio reference quality system.
In fact the first thing you should invest in is a set of reference speakers for your home, you can do all your programming and set up. Your PA needs to sound as good...just louder