Yamaha DGX-670 DGX-670 Reference Manual - Page 8

 Harmony The types from Standard Duet 1 to Strum apply the harmony effect to notes played in the right-hand section of the keyboard according to the chord specified in the left-hand section of the keyboard. (Note that the "1+5" and "Octave" settings are not affected by the chord.) If you want to use these types with the Style stopped, set the Stop ACMP parameter to a setting other than Disabled in the Style Setting display (page 25). • When the [ACMP] button is on and the Left part is off: Split Point Chord section for Style playback and Harmony effect 2 • When the [ACMP] button is off and the Left part is on: Split Point Voices Main and Layer Voices Left Voice and chord section for Harmony effect • When both the [ACMP] button and the Left part are on: Style Split Point Left Split Point Left Voice Main and Layer Voices Chord section for Style playback and Harmony effect The Multi Assign effect automatically assigns notes played simultaneously on the right-hand section of the keyboard to separate parts (Voices). Both of the keyboard parts [MAIN] and [LAYER] should be turned on when using the Multi Assign effect. The Main and Layer Voices are alternately assigned to the notes in the order you play.  Echo When Echo, Tremolo or Trill is selected, the corresponding effect (echo, tremolo, trill) is applied to the note played in the right-hand section of the keyboard in time with the currently set tempo, regardless of the [ACMP] and the Left part on/off status. Keep in mind that Trill only works when you hold down two notes on the keyboard simultaneously (last two notes if more than two notes are held), and it plays those notes alternately. 8 DGX-670 Reference Manual