I was wondering for quite some time. . .some acoustic pianos have integrated MIDI ports on them, with sensors that capture the vibrations of the strings and convert it to MIDI data. I was wondering. . .if you were to record a piano piece like this, would it capture the sympathetic vibrations and overtones in the MIDI? For example, if you softly layed down a C major triad in C4 and played staccato notes around it, would it capture the chordal harmonic notes harmonizing softly with each note?
I think you are referring to midi retrofit systems (Yamaha Disklavier and such). These transmit accurate midi data of keys (position, length, velocity) and the use of pedals (sustain, sostenuto, una corda). The complex interaction between strings, soundboard, cabinet and pedals (such as string resonance) cannot be sent as midi but must be recomputed.
That's right. Another way to put it is that midi captures only keystoke and pedal movement information, and only to the extent that keys and pedals have the sensors which generate the information. As long as the sensors acurately capture the piano perfoprmance, if the piano also has playback solenoids to acurately recreate the performance, you'll be able to capture all the sounds and resonances of the original performance when you cause the piano to play back the recorded midi... using microphones.
Note that not all midi-fitted pianos have sensors and/or solenoids on the pedals. Of those that do, most only deal with the sustain pedal and not soft or sostenuto pedals. And most only record pedal movements up and down, not all the fine gradations a skilled pianist might employ.