How to work with interval ear training
The module plays two notes and asks which distance lies between them. You pick a level first: the lowest level offers only unison, fourth, fifth and octave, the distances whose sound differs most clearly. Major and minor thirds and sixths appear once you hit those reliably, then the seconds, and the tritone cases last. That order is not arbitrary. Starting with all twelve intervals at once means guessing, and guessing teaches nothing.
There are three modes for direction. Ascending is the normal case and the one that matters most at the start. Descending has to be practised separately, because a descending interval does not simply sound like an ascending one turned upside down. In harmonic mode both notes sound together; you no longer hear the path from note to note but the colour of the combined sound, and that is a skill of its own.
Every question can be replayed as often as you like. Use that deliberately: listen three times and then decide, rather than clicking quickly. Wrong answers are resolved and the interval is played again, and that moment right after a mistake is the one that teaches. Fifteen to twenty minutes in one sitting is sensible; after that, attention drops noticeably.
What an interval actually is
An interval is the distance between two pitches. It is named after the number of staff steps it spans, from the unison as the smallest to the octave as the eighth step. Because the steps of a major scale are not all the same size, the count needs a qualifier: perfect for unison, fourth, fifth and octave, major or minor for second, third, sixth and seventh. Diminished and augmented appear when a note is altered chromatically.
Physically, every interval is a frequency ratio. The octave is 2:1, the perfect fifth 3:2, the perfect fourth 4:3, the major third in just intonation 5:4. The simpler the ratio, the calmer and more fused the combined sound. The tritone, the square root of two in equal temperament, has no simple ratio and therefore sounds suspended and undecided. Once you have grasped that connection, consonance and dissonance stop being a matter of taste and become an acoustic property.
On a keyboard every interval equals a fixed number of semitones: minor second one, major second two, minor third three, major third four, perfect fourth five, tritone six, perfect fifth seven, minor sixth eight, major sixth nine, minor seventh ten, major seventh eleven, octave twelve. Knowing that series by heart helps you check your reasoning, but it does not replace hearing.
Anchor songs — the trick from practice
The most reliable way to recognise an interval is a song that begins with exactly that interval. For the ascending fourth you can use the opening of "Here Comes the Bride", for the ascending fifth "Twinkle, Twinkle, Little Star", for the major sixth the start of "My Bonnie Lies over the Ocean". The minor third sits in the two-note call of "Hey, Jude" and in the cuckoo call; the major third opens "Kumbaya". Descending intervals need their own anchors: the descending major second begins "Mary Had a Little Lamb", the descending perfect fourth "Born Free".
What matters is that you pick your own songs, not someone else’s. An anchor only works if you can sing the tune without thinking. Write yourself a list of twelve lines, one per interval, and fill in whatever comes to you instantly. That list becomes redundant within two weeks, because the ear starts taking the shortcut directly, but for those two weeks it is the backbone of your training.
Second practical tip: sing the answer before you click it. Your voice forces a decision that a mouse click alone does not require, and it links hearing to inner imagination. Students who sing along progress noticeably faster than those who only listen.
Common mistakes
The most frequent mistake is confusing the fourth and the fifth. Both sound open and hollow, and anyone listening only for that quality is effectively flipping a coin. The cure is to listen to the direction of the tension: the fourth pushes upward and wants to resolve, the fifth stands still. One anchor song per interval settles the matter for good.
The second most common mistake happens beyond the octave. A major seventh and a minor ninth feel similar at first because both sit close to the octave. In such cases listen deliberately for whether the upper note is still below the octave or already above it.
A third mistake, rarely discussed, is practising too loud or on poor headphones. Distorted bass makes low intervals unrecognisable. A moderate level and reasonably linear headphones matter more for ear training than sheer volume of practice. And finally: ten minutes every day beats two hours once a week. Ear training is habituation, not effort.