The Ear training reference article from the English Wikipedia on 24-Jul-2004
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Ear training

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Ear training is what musicians do to improve their ability to identify, relatively, chordss, intervalss, rhythms, and other elements of music. Singing plays an important part in ear training, since one must be able hear music in one's head and match pitch before it is possible to sing it reliably. One does not need absolute pitch to succeed at ear training and the development of relative pitch is the goal of ear training.

Transcribing recorded music is one way to practice all of these things. Some music teachers teach their students relative pitch by having them associate each possible interval with the first two notes of a popular song. Here are some examples:

Other methods include solfege, sargam, and numerical sight-singing.

Further reading