I agree with everything that's been said.
I record myself all the time as a learning tool. I record everytime I improvise and I record in a few different ways. At home, I only have a digital piano, so I'm pretty much stuck with recording directly to hard-disc. That's OK though, I use this for the "technical analysis" mostly. Once I feel a piece is adaquetly developed I start wanting to record to further understand the aesthetic quality of what I'm playing. To do this, I'm lucky to have access to a selection of baby-grands, one being in the sanctuary of a church (when it's not in use) - nice 80' ceilings, balcony, baby Steinway. For this situation, I have done a few different things.
First there is close micing, where you take two mics and place one over each end of the soundboard, placement is subjective, it's about experimentation. This approach will give you a very clean, up close and personal sense of the piano, and you'll get that "Stereo image" you're talking about. Mono recording of a piano is absolutely out of the question. I have also taken my mics and set them up 10' or so back from the piano, 10' or so up in the air. This gives a good sense of the piano, but you get room reverberation and the overtones, which, to me, is more aesthetically pleasing than the close micing, which is more appropriate in a studio session I think.
Finally, and this is especially great that I have access to this sanctuary - placing the mics up in the balcony, another 10' or so up in the air, and at the back of the room. You get such a full and beautiful sound from that perspective. (look for my mp3s of my recital last week coming soon, this is how I recorded that).
To be able to accomplish that however, you need appropriate mics. You could not take one (or two) of your computer mics and stick them that far out - the low quality mics and low quality preamp would introduce so much noise, due to the gain you'd have to add, to make it worthwhile.
Knowing I would be doing alot of piano recording, and wanting to experiment with mic placement, it was important that I invest in mics that were versatile. This costs money, but if you are really interested in recording yourself to learn how you sound aesthetically, it's a worthwhile investment. There are a number of options for mics, from a couple hundred dollars to a couple thousand. I use a pair of AKG C414BXL-II large diaphragm condensor mics. They work very well in all of the above mic'ing situations. (I even record live jazz combos with them)
Ted Wrote:I can think I've been playing rubbish and then listen to it the next day and think it was marvellous or, fortunately more rarely, the other way around. But of course, this effect really is in my mind and has nothing to do with recording.
I hear ya. I experience the same thing all the time. Usually though what I think is really good while I'm playing it, I tend to think is nothing special when I later listen to it. This is very unstructured improvisation however.