If the intended comparison is between recording a live sound and the sound produced by a synthesizer then there can be a huge difference between the two.
The live sound, though recorded, is from the original instrument and therefore the complete sound. A synthesized sound is produced from a recorded clip of sound. Depending on the quality of the recorded sound clip there could be little difference or a significant difference.
The organ in New York that uses Definitive Technology has an incredible database of recorded sounds to produce the notes. I'm sure it sounds pretty close to the organs that it's sound clips were recorded from.
The live sound, though recorded, is from the original instrument and therefore the complete sound. A synthesized sound is produced from a recorded clip of sound. Depending on the quality of the recorded sound clip there could be little difference or a significant difference.
The organ in New York that uses Definitive Technology has an incredible database of recorded sounds to produce the notes. I'm sure it sounds pretty close to the organs that it's sound clips were recorded from.