Hello everyone. Nice to meet you all! I would like to know if anyone noticed a weird sound when you hit the 16th white key from the left and also the 11th black key from the left B and Bb keys one octave down from the center? It makes a weird noise and the sound vibrate very powerfull causing dissonant overtones. I've bought this model on Walmart here in Brazil so i called the service center because this is very annoying for me so they replaced it for me with brand new one last friday... but unfortunately it did not solve the problem at all.. still there.. so what happened? I don't understand... problem with the way the piano was built? the local that i placed the piano? what? Also i play the piano at night using a headset and there is no problem at all with the sound so it must be the piano speakers somehow... not problem with the keys itself... is there anything i can do to fix this... a friend of mine brought his PX-350 here so we could test it side by side and on the 350 there is no problem at all... so maybe i will return this and get the 350 with stand and pedal bar... but first i must find a way around this... so if anyone know what is going on please help me out!! Sorry for my bad english and i wish you all a great weekend!! Thanks for everything!! Best Regards, Queiroz