RohitZedek

Well, you can try 2 things. 1. Use a high quality earphones to listen to piano sounds. See if you get the harmonics. If it persists then it's okay And your keyboard speakers are also working well. 2. connect your CDP 230 to PC and run some midi app like FLStudio or Garageband. Try playing grand piano or stage grand from the app and route the sounds to your keyboard speakers and then to the high quality earphones. This way you will get a fair idea of your keyboard sound and the original piano sound. BTW in my case the piano sound from earphones is excellent, far better than onboard speaker.