Bill,
Every venue has its own accustic pecularity, particularly when using a sub. For example, there is a significant difference in sounds transmitted from the sub when playing in rooms with concrete floors, V/S wooden floor, carpeted floors, tile floors, playing on a stage that's a few inches off the floor, playing from a stage that's 4 feet higher than the floor, etc. Additionally, the position of the sub in relation to the wall, the direction it's facing, and the volume ratio of sub to satellite speakers all have a huge bearing on the overall performance of the system.
A general rule of thumb for the volume ratio is the sub should be approximately 25 to 40 percent of the satellite volume. Most of the time, again this is subjective, sub volumes higher than 30 percent are excessive.
Additionally, the gobal EQ of your keyboard is another important factor and as a significant bearing on the overall sound. This too will vary with different sound systems and venue configuration. The best advice I have is to record a midi file using the PSR-2000, something that would use the styles and voices that you would normally use for a particular job, put the midi file in the keyboard and walk around the room listening to the system. What you heard on stage may not be the same that folks sitting at the bar or far tables may hear. Then you can make the needed adjustments and determine if this is the sound you wish to hear.
Good Luck,
Gary
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Travlin' Easy