The Alesis Concert is a full-featured digital piano with 88  full-sized semi-weighted keys with  adjustable touch response. The Concert features  10 realistic built-in voices: Acoustic Piano,  Bright Piano, Electric Piano, Harpsichord, Drawbar Organ, Church  Organ, Synth, Strings, Bass and Clavi.  Customize the voices by combining any two at once  in Layer Mode for a full, rich tone.  They can also be assigned to only the left or  right hands in Split Mode. You can even  add adjustable Reverb and Chorus to further  tailor your sound. With powerful 20-watt built-in  speakers and a 128-note maximum note polyphony,  Concert delivers ultra-realistic sound with great playing experience. The Alesis Concert has an incredibly useful feature called "Lesson Mode."  This feature divides the 88 keys into two zones  with the same pitch and voice. This enables both  the student and teacher to easily watch each other  and play together without having to  take turns or reach over one another.  Concert also features a ¼” (6.35mm) headphone  output which mutes the internal speakers for  convenient, quiet private practice. In addition to the ¼” (6.35mm) sustain pedal input  (pedal included) and the ¼” (6.35mm) stereo  headphone output, Concert also features stereo  RCA outputs to connect to a recorder,  mixer, amplifier or other sound system.  Concert also features a USB-MIDI output for connecting  to a computer and using educational software or virtual instrument plugins.  Concert can be powered using the included power supply  or by 6 D Cell batteries (not included).