Roland DP90 用户手册

You can divide the keyboard into left and right zones so that two people can play the same range of pitches, just as though there were two pianos.
This function is called Twin Piano.
For example, you could use Twin Piano to allow a student to play along with their teacher.

The [Twin Piano] button will light, and the Concert (Concert Piano) tone 

will be selected.
When you turn Twin Piano on, the keyboard and pedal settings will be as 

shown in the illustration.

If Twin Piano is on, damper resonance will not be applied; this may cause the piano to sound different.

Select the tone to be played (p . 14) .

The left and right sections will have the same tone.

The [Twin Piano] button will go out.

The display will indicate Twin Piano mode.

1
(default)

The sound of the right-hand keyboard zone will be heard more loudly from the right speaker than from the 

left speaker.
The sound of the left-hand keyboard zone will be heard more loudly from the left speaker than from the right 

speaker.
When using headphones, you’ll be able to hear the other person’s playing.

The sound of the right-hand keyboard zone will be heard only from the right speaker. 
The sound of the left-hand keyboard zone will be heard only from the left speaker.
If you’re using headphones, the sound of the right-hand keyboard zone will be heard in your right ear, and 

the sound of the left-hand keyboard zone will be heard in your left ear.
*  Ambience will turn off.
*  For some tones, the sound might not be divided to left and right.