I tried to explain it and it came out to long.
I don't have any recording equipment...none what so ever.
I have a Piano, a computer and at the time I had Cool edit pro what is now known as Adobe audition and a pare of simple 6$ worth sony earphones(the small ones which go inside the ear)
I used an extension chord for the earphones and plugged them into the mic Jack in my sound card.
I glued(using masking tape) the right earphone inside the piano box near the high octaves and the left near the lows so the won't move)and closed the box.
then I set the mic recording level very low because it gets really loud inside the piano box you don't want your sound to come out distorted.
the recording came out loud and clear.
from here the mixing options are much wider.
something I learned from the whole experience back then
1.You can use any kind of earphones as a mic when you plug the in the mic jack.
2.In case you don't have a studio in your house that's soundproof and has wooden panels on the walls for great acoustics...like in my case where you have a concrete wall and a window to the constant rush hour road and someone chooses to wash the dishes right during the recording.
being the earphones inside the piano box with low recording volume, if the noises in the room are not too loud you won't hear them on the recording.
3. when you record a piano you must have a ringy piano. I have a 40 year old piano from belarus that has a ringy sound but most of my friends' piano i got to play had a deaf sound to them, yours sounds a little deaf too and I don't mean the under water sound which came out after the mixing. in these cases I would always recommend using an organ or piano samples.I also know world class pianists "sand the hammers with sand paper" to have a more ringy sound on the piano but I woudn't recommend that unless you know what you're doing.
that's basicly it, hope this helps.
wow this came out longer then before