First off piano by ear is mostly based off your understanding of chords, and progressions. The ability to play piano chords, and know them by heart is a must have to pick out songs without sheet music. And anyone can get a chord chart, or better yet know the pattern to form chords and memorize them.
Piano by ear is pretty much, you hear a song and by just hearing it you can go to a piano and repeat what you hear. So what is the real secret to doing this. Most people say it’s a special talent or a gift that you either have or you don’t. But I say anyone can learn to play piano by ear if they just understand the concept of music theory.
First off you have a scale, and you should know how to make up a scale. But the first thing to do is instead of thinking in terms of letters you need to think of them as numbers. So in a C scale C would be 1 D would be 2 E would be 3 and so on until you get to 7 which is B. The reason for this is so when you change keys they numbers are the same and if you are using letters when you change keys the letters change.
So when I tell you that the 2 chord in a scale is a minor chord that applies to every key, I can’t say the D is a minor chord because when you change keys the D will change.
The formula for which chord is off of what number is this the 1 chord is going to be major, 2 minor, 3 minor, 4 major, 5 major, 6 minor, and 7 is diminished. So from there you learn the major and minor chords off of those numbers of the scale. But the real mistake everyone makes when trying to play by ear is this.
They try to pick out the melody, that will not make a song sound like the real song you are hearing. The true secret behind playing the piano by ear is, after you know the scales as numbers, and know what kind of chord you will form off each number, major or minor. You listen to a song and don’t even really pay attention to the melody at first, listen for the bass note. You can write the song lyrics down and listen real close for the bass note and as you hear it change you can write the note number over the lyrics.
After you have the number over the lyrics on paper, you can then go to your piano and play the number based on a minor or major then put the melody note on top. And you will find that what you are playing sounds and feels just like the song you were hearing.