1. Why in the heck is there so much energy right above 300 Hz ?
2. Did you just walk into a spare bedroom in the house and find a piano there ? (joking)
Really though, if you actually went out and got a piano to do this, you are pretty dedicated to it. I wouldn't mind being involved and I know someone else who would love to get into this, at least a little bit. Where the hell are you ? If you are in reasonable driving distance I can bring a few things. I got a trumpet, violin, accordion, damn if I can remember what else right now, a few guitars of course and a drum or two, which you don't need of course.
Probably a pipe dream because you are probably in Saskatchewan or something.
And if I ever get subjected to your spectrum analyser, we shall record this very special instrument I made.
A while back I had to trim a very little piece off some wood to make it fit. the scrap ended up being about 3/32 by 3/32 square, something like that. It was great. I tapped it on the top of a can and could actually make songs by varying how far it hit. (from my hand) Unfortunately I did not have a mic at the time. (actually now I have three but I can't find two of them, the better ones of course)
Alright, to explain how these things sounded, remember the song "Popcorn" ? I could play it on those. No electronics except amplification.
Actually I just checked and I am wrong, I could not play it on my little chop(ped) sticks.
Maybe if they were longer.