Ear Trainer
Intervals, chord colors, and progressions, played to you and named by you. This is the skill that turns hearing music into understanding it.
The idea
Every musical distance has a flavor your ear already knows from a thousand songs; you just haven't attached names yet. That's all ear training is: hear a sound, name it, check, repeat. Attach the names, and suddenly you can find a melody on the neck, name a chord from across the room, and learn songs without a chart.
The three drills
Intervals is the distance between two notes, the atoms of melody. Chord colors is the mood of a stack: settled or restless, bright or dark. Progressions is the largest unit, recognizing the four-chord stories that power most songs. They build on each other, and each has three levels, so start where it's almost easy.
How to practice
Play the sound as many times as you like before answering, and sing it back before you guess: singing forces the ear to commit. Five focused minutes daily beats an hour on Sunday. When a level stops resetting your streak, move up. Wrong answers teach the most, so read the flavor line every time.