There are two basic technologies used for sound production in digital organs. The most prevalent is sampling whereby pipe organ and other instrument sounds are recorded, digitized and stored in an organ’s memory for playback. One organ company promotes a different approach referred to as physical modeling that does not use pipe recordings, but instead algorithms to produce pipe-like sounds.
In today’s high-tech world, modeling is often used when attempting to predict an unknown outcome that is affected by multiple variables, such as the weather. As a hurricane is developing offshore, computers use models (algorithms with inputted variables) in an attempt to determine where the hurricane will land and at what strength. As historically demonstrated, the predictions are often inaccurate. Another example is the current difficulties experienced by Boeing with its 737 Max aircraft that is related to a modeling weakness. Boeing attempted through modeling to have the plane’s flight controls respond in a manner similar to that of the older 737 models in an effort to avoid the need to retrain pilots. The result has been problematic, as has been publicized.
Unlike requirements for predictive outcomes, with digital organs the desired outcome is fully understood in advance. For example, should a digital organ builder want to produce an instrument based on a famous builder, such as Cavaillé-Coll, sampling enables the builder to take advantage of the genius and art of Cavaillé-Coll to re-create the sounds accurately, assuming a quality sampling system is used. Modeling, on the other hand, begins by attempting to create generic pipes’ sound. However, models that can “think” and act like Cavaillé-Coll pipes is well beyond current technical capabilities. This is why sampling offers the best way to accurately reproduce pipe organ sound.
Another example of a modeling weakness is speech. While this technology is used to enable computers to speak, the results are mechanical and obviously contrived. Similar flaws occur when a model is used to create a musical sound. Irrespective of these weaknesses, modeling is promoted by the one digital organ builder as advanced technology.
In a church organ, sound producing technology is only advanced if it can produce the most pipe-like sounds. The ultimate test of any digital organ’s technology is tonal results. Below is a link to a video that includes an organ with sampling technology played along-side of a fine pipe organ in the same room and operated by the same console. Most cannot determine which sounds are produced by pipes and which are produced digitally. This is the true test of advanced sound producing technology.