Here's what Yamaha say... The luxurious tone and expressive ease of playing stays true to the basics of an acoustic piano. It almost plays itself, resonating with the sound of music you feel within. Start your day with music and a huge smile on your face the ARIUS piano creates an urge to continue playing. Feel With an 88-key piano action, the GH3 (Graded Hammer 3) keyboard and GHS (Graded Hammer Standard) reproduce the touch of an acoustic piano, from a naturally heavy feel in the lower keys to a lighter touch in the upper octaves. The GH3 keyboard of the YDP-165 and YDP-S55 even provides a grand piano-style response and feel, allowing rapid note repetition and authentic expressive control. Moreover, theres a half-damper feature which authentically replicates the damper action of a grand piano, providing rich expressive variation. One of the allures of the grand piano is the sympathetic resonance created by the vibration of the entire instrument. All ARIUS models elaborately reproduce this rich sympathetic resonance through a groundbreaking technology called Virtual Resonance Modeling Lite (VRM Lite). VRM Lite creates a richly varied sound by simulating the complex sympathetic tones created when the vibrations of the strings are propagated to the soundboard and other strings, corresponding to the timing and intensity of key playing and pedaling. Enjoy More Naturally, all ARIUS models have an authentic grand piano sound, but they also feature various other built-in instrument sounds, with a total of 10 Voices including electric piano, organ, vibraphone, and strings. All ARIUS models also have 353 built-in songs, including 50 famous classical songs, and 303 comprehensive practice exercises from famous composers, such as Beyer, Burgmller, Czerny, and Hanon. The instrument is also compatible with Yamaha's free Smart Pianist app simply download the app to your smart device and connect it to the instrument. Smart Pianist With the Smart Pianist app, you can easily operate the various Voice functions of the instrument and use it to view scores of the built-in songs. It also features a comprehensive Piano Room function for changing the tonal quality and resonance settings of the piano sound. Design While based primarily on straight lines, both YDP-165 and YDP-145 have a stylish design that incorporates elegant curves that are typical of a grand piano. The piano cabinet of the YDP-S55 and YDP-S35 have a slim depth that lets you neatly install it in any room, and makes for a chic, stylish design that effortlessly enhances your living space. Moreover, you can choose from a variety of color variations to find the one that suits your interior and personal taste. Specification Size/Weight Width1,353 mm [53-1/4"] Height792 mm [31-3/16"] (Key cover open: 976 mm [38-27/64"]) Depth309 mm [12-3/16"] (Key cover open: 317 mm [12-15/32"]) *With anti-fall brackets attached, the depth is 382 mm [15-3/64"]. Weight40.0 kg (88 lbs., 3 oz.) Control Interface Number Of Keys 88 Keyboard TypeGH3 (Graded Hammer 3) keyboard with synthetic ebony and ivory keytops Touch Response Hard/Medium/Soft/Fixed Number of Pedals 3 Half Pedal Yes (Damper) Functions Damper, Sostenuto, Soft Cabinet Key Cover Style Folding Voices Tone Generation Piano Sound Yamaha CFX Virtual Resonance Modeling Lite (VRM Lite) Yes Key-off Samples Yes Smooth Release Yes Polyphony (max.) 192 Preset Number of Voices 10 Effects Reverb 4 types Intelligent Acoustic Control (IAC) Yes Stereophonic Optimizer Yes Functions Dual Yes Duo Yes Songs MIDI Number of Presets - 10 Voice Demo Songs, 50 Classics, 303 Lesson Songs Recording Number of Songs 1 - Number of Tracks 2 Data Capacity Approx. 150 KB/Song (approx. 11,000 notes) Functions Metronome Yes Tempo Range 5 280 Transpose -6 0 +6 Tuning 414.8 &ndas