Get the Casio Privia PX-770 here: https://www.sweetwater.com/store/detail/PX770BK
Get the PX-870 here: https://www.sweetwater.com/store/detail/PX870BK
To reproduce the sound of the finest acoustic grand pianos, the Privia PX-770 and PX-870 feature Casio's proprietary AiR (Acoustic and intelligent Resonator) processor. Accessing more than three times the memory of the previous generation, the AiR processor utilizes grand piano samples recorded at four dynamic levels of sampling to deliver grand piano sounds with long natural decays and remarkable expression. To further the grand piano experience, AiR adds realism by simulating the sound of the open strings when the dampers are raised by the pedal.