Hi emill,
Thanks for listening and for your nice compliment on my playing. I appreciate it! Did you listen to only one of the preludes, or all four? Hearing all of them is only 5 minutes. These are true miniatures.
In the A-B method of recording, two microphones, preferably a matched pair (one serial number apart showing they were both made at the same time) are used to create a stereo recording. Depending on room acoustics the two mics are placed out in front of the grand piano's curve at a distance of 5 feet or even farther away. In my room I position them 8 feet in front of the piano, as my Baldwin is very powerful in the living room. Because every music room acoustic, piano, mics, recorder, and pianist are different, the positioning decision involves extensive experimentation until the optimal distance or "sweet spot" is discovered. Thereafter, the same positioning is always used. The two mics for best results should be small-diaphragm condenser mics with omni-directional capsules to incorporate piano sound and room ambiance too. Cartioid pattern mics are not as successful in enabling a rich, blended, and finished sound. They are justified if the pianist has to contend with loud external sounds outside the dwelling. They must be on adjustable stands exactly side by side and parallel such that sound will reach both mics simultaneously. The separation between the mics themselves is always 12 inches exactly. For more treble the two stands can be moved to the left toward the hammer line in the piano while maintaining the 12" parallel separation. Or if more bass is desired, they can similarly be moved to toward the right, or tail of the piano while maintaining parallel 12" separation. As for the stands, the typical elevation of the mics on stands would be about 4 1/2 feet high in a room with a standard 8 foot ceiling. If the piano lid is open on the full prop, then the mics are inclined upward pointing at the top edge of the open piano lid. The sound there is pure, whereas if the mics are pointed straight ahead at the middle of the open lid there is too much reflective sound "wash" from the lid. If only the short "singer prop" is in use to hold up the lid, then the mics are declined downward but still aimed at the top edge of the lid. For best results the piano should be recently tuned, the recorder should be a very good table top model, mics should collect a neutral, natural sound from the piano without adding any color to it, and mic cables, while not having to be the best, should be close to it. The cables generally use XRL connections. Many hand-held recorders offer one or no XRL connections, that is you must use their on-board mics, or you might be able to use one mono external mic. Table top models offer more features and recording capacity. A-B configuration is the best choice for classical music. Placing mics inside the piano or very near the piano using XY configuration emphasizes the percussive element of the instrument. That's good for jazz and pops, but not classical music. Bottom line: Given all of that, the most important element in the recording process is always... the pianist!
I hope that explains it sufficiently.
David