The way I've been taught to play (not when I was a child, but later) involved a a lot of listening (obvious) and a lot of "imagination", carrying the sound in my inner ear before the next interval. (Does this makes sense to you?) "judging the interval", "singing it", but obviously this is something that goes on internally, purely speaking the key has been played, and then you have the next. However, I find the sound changes drastically when listening that way, objectively the sound has a different projection.Now my questions is, do you have a "mechanical" way to explain this? Is there something "else" I'm doing that I'm not aware I am?
This is a good but complicated question, I think!
Everything we do at the piano is ultimately -- if successful -- an illusion.
The piano is a percussive instrument. It is a series of felt hammers that strike strings to produce sounds.
Once the key is played the hammer is catapulted towards the string -- and we only have a very small fraction of a second in which we are in control of the speed with which we send the hammer on its way.
And now we are onto the next note, and the next, and next and so on repeating this basic mechanical task.
How then do we create a smooth crescendo for instance?
We can't. Its not possible like a violinist can or a singer can with a continuous stream of breath across vocal chords.
All we can do is play each note somewhat louder than the next in a measured planned way to create the illusion of a continuous crescendo that "fools" the ear of the listener.
It is much like the idea of "motion pictures".
If we watch a movie, it is really NOT people on the screen showing emotion, or doing what ever they do.... it is the projection of individual still pictures taken with a camera and shown individually on the screen in quick succession one after the other thus creating an illusion for the audience of "real people living real lives."
This, for instance, is why playing a Bach Prelude and Fugue musically WITHOUT peddle is so difficult.
A compete illusion must be created from scratch for the listener, complete with crescendo, diminuendo, pulse, rhythm, terracing, voicing, etc., etc.
So I think its a fair analogy to say the pianist with each note is taking a "still musical picture"
visualized in her imagination and mechanically transmitted through the key to the hammer hitting the string, which -- when connected with the other "still musical pictures" of a piece of music, will result in a convincing illusion full of emotion, thought, metaphor and whatever else the artist has intended.
Therefore, I think we start with an artistic idea of a piece of music, be it metaphorical or emotion or sound, and "deconstruct" this image to its parts in order to bring it alive at the keyboard one thought out note at a time.
I don't know if I answered your question or even got close to it, but I hope this helps!
PS
I mentioned Bach because I really enjoyed listening to you on your site!