How can I play VST software using my Kawai piano and hear it through the piano's speakers?
Connect via USB MIDI to route your playing to the VST, then route the VST's audio output back to the piano's audio inputs via an interface.
To use VST software instruments with your piano while monitoring through the piano's speakers: Connect your piano to a computer via USB MIDI. Install your DAW and configure it to receive MIDI input from the piano.
Route the VST's audio output to your computer's audio interface, then connect the audio interface's output to the piano's Line In input (if available). Adjust the mixer in your DAW and on the piano to balance the levels.
Note: This setup requires a piano model with Line In functionality and a separate external audio interface. The latency of this chain depends on your computer's audio buffer settings.