The Ear Training Lab

This idea is simple — play each major scale along to the recording until you find the one that sounds the 'nicest'. Playing the scale for the key the piece is in should sound pleasant, and all the notes should sound as if they 'belong'; playing any other scale will probably sound varying levels of dissonant, or be unpleasant to hear.

For example: if a recording is in the key of C Major, it will (generally) stick to the notes of the C Major scale — C, D, E, F, G, A and B. Playing a D Major scale on top of this (notes D, E, F#, G, A, B, C#) will sound dissonant, as the F# and C# notes do not belong in the key the recording is in and will stick out as odd or unpleasant. Likewise, playing a B♭ Major scale (notes B♭, C, D, E♭, F, G, A) will sound unpleasant because the notes B♭ and E♭ do not belong in the key the recording is in. Scales with more non-matching notes will sound less and less pleasant — for example, F# Major only shares 2 out of 7 notes with the scale of C Major, whereas G Major shares 6 out of 7.

You can make this easier by limiting the game to only major keys and scales you are familiar with, and adding extra keys as you learn them.

A piece of music in a single key will feel like it gravitates to a single 'home' or 'resting' note. This is because all the notes in the scale of that key produce some kind of musical tension within the context of the piece, the notes it uses and the harmony — moving through this tension gives music its emotion. The note with the least musical tension in a key will be the 'tonic', or 'root note' — this is the note the scale begins on; i.e. in the key of C Major, the tonic is the first note of the scale, 'C'.

If you play notes on your keyboard whilst the recording is playing, some notes will sound like they really belong, whilst others will not. Generally speaking, the note that sounds most like it 'belongs' will be the tonic, which tells us which key we are in.

Play notes until you find one that really fits — this is a feeling you can practise — then select the major key that corresponds and see if you are correct!