It's a midi controller keyboard (no internal sounds) with a hammer grand piano key action, very realistic key feel. So obviously you connect it to a pc/mac via usb to play downloaded vst pianos etc.There are thousands of free piano vsts as well as top of the range paid vst downloads.I've ran it through my Roland stereo amp (via audio interface) and yes a very realistic grand piano sound etc..It's about 2 years old from brand new,so it's in perfect working order