I am sorry, but wouldn't the Synthesia forums be the better place to ask this? These are the Pianoteq forums, which has nothing to do whatsoever with Synthesia. You can use a Privia piano to control Pianoteq, of course.
From what I understand, Synthesia is more or less just a MIDI player. That is, it plays a MIDI file at a selectable speed, apparently using the computer's audio system (although I may be wrong about that). Besides just playing the song, it also produces a scrolling vertical piano roll display (the 'falling notes' thingy) and a virtual keyboard on screen, so you see what keys are pressed and when.
When you connect a MIDI keyboard or piano the the computer, Synthesia seems to use this mainly as controller input. That is, the actual audio is always coming from the computer. Makes sense, since quite a lot of MIDI controllers don't have audio capabilities at all.
That said, the Privia pianos do have built-in speakers. In other words, you will hear sound from the speakers when you press the keys, even when connected to the computer and Synthesia. However, you will hear the Privia's (quite nice) piano from its own speakers, and the (quite awfull) GM piano sound made by Synthesia from the computer speakers.
Hope that helps.
Last edited by kalessin (08-06-2014 16:47)
Pianoteq 6 Standard (Steinway D&B, Grotrian, Petrof, Steingraeber, Bechstein, Blüthner, K2, YC5, U4, Kremsegg 1&2, Karsten, Electric, Hohner)