Roland AT900 Music Atelier Owner's Manual page 252

Connecting with External Device
A Setup for a Recital
Bass, drums, and other sounds are output separately, and a mixer
is used to adjust the volume balance.
Speaker L
A Setup for Enjoying Ensemble Performance
By producing the accompaniment and rhythm from external speakers,
you can enjoy the sensation of performing together with an orchestra.
L
Powered Speaker
250
AT-900/AT-900C
Main Output
AT-900/AT-900C
Aux/Drum Output
Bass Output
Aux/Drum Output
Mixer
Amplifier
Aux Out : ON
Aux Out Mode: SEPARATE
Speaker R
Aux Out : ON
Aux Out Mode: ENSEMBLE
R
Powered Speaker