Train your ear for music composition/improvisation. EarTrainer X is an educational application that was designed for the composer/improvisor in need of increased skills in the aural identification of modal melodic and harmonic materials. The app creates an infinite number of examples of tetrachords, modes, scales, and single or groups of modal chords. The examples are displayed on staves as with any notation program for the checking of answers. There are three levels of difficulty with the third containing some very advanced and beautiful modal chords. As a bonus, some of the examples in the multiple chord level could be developed into compositions putting the app in the agorithmic-composition category.