"Last summer I purchased a Kurzweil PC-88 for our Church to use during worship services. The problem is that when the keyboardist switches from a piano to the organ sound the volume increases dramatically, which sends the sound man scurrying to compensate. Is there an easy way with the keyboard itself to override this increase, short of re-programming all the organ sounds? If not, I have a spare compressor; could it be set up to force a consistent volume from the keyboard to the mixer?"

Unfortunately there is no global parameter called "Make all the Organ Programs Softer." You would have to reprogram those patches. The compressor would be a last resort, and it isn't likely to help that much because a lot of what you are fighting is the "perceived" volume difference between the two sounds. In most modern keyboards a fair amount of thought goes into the relative volumes of the sounds, but the decisions made aren't appropriate for everyone and every circumstance. Unlike a piano, the organ is really designed with the idea of a volume pedal in mind. To have an organ sound playing at full volume all the time just doesn't work that well for most players. This type of problem is reported more frequently by players with a light touch because the piano sounds will decrease in volume whereas the organ sounds (correctly) play at full volume regardless of velocity. This can be compensated for somewhat in the Velocity Curve for the PC-88. Setting it to "light" will bring the piano programs closer in intensity to the organ programs. A compressor set strongly enough to correct the volume differences would probably affect the piano sounds adversely. The easiest solution may be to employ a continuous control pedal assigned to volume and have the "organist" learn to use it.