Virtual Organs offer “wet” samples. While simplifying the sampling process, this approach includes tonal compromises.
Most digital organs rely on sampling technology in which digital recordings of pipe sounds stored in the hardware memory are reproduced when the organ is played. Organ builders that rely on PC’s for tone generation avoid the cost associated with designing and manufacturing specialized components. The techniques used to acquire and playback the samples (sounds) in PC-based instruments is also the least expensive, instead of the best.
The most accurate and detailed tonal results require recording pipe sound without any extraneous background noises or the room’s own reverberation. This demands that the microphone be placed close to the organ pipe during recording. However, this “dry” sampling technique is a more exacting and time-consuming process than merely placing microphones farther out in the room (“wet” sampling).
PC-based organs, “Virtual Organs” use the wet sampling approach in which the microphone is placed out in the church when pipes are recorded. The recordings include the “wetness” of the building’s acoustics (reverberation), as well as extraneous mechanical clicks and clacks from the pipe organ, and other noises. Since the acoustics of the original room are an integral part of those recordings, there is no way of removing them, even when not desired. When an instrument that uses wet samples is played in a room with its own natural acoustics, the result is acoustic “overload”. Also, the extraneous noises recorded along with the pipe sounds become unmusical artifacts in the pipe sound’s reproduction.
PC-based organs use wet samples for two reasons: 1) the recording process is simpler and less expensive, and, 2) single PC’s lack the processing power to simultaneously produce pipe sounds and independent acoustics that can be adjusted (voiced) separately. This inhibits a PC-based organ’s ability to be properly voiced to its surroundings.