Instructions
Create your first music video to unlock the cat suit, cheerleader, hand clap, recorder, sitar and toy piano instruments. You create music videos by completing a "Custom Jam." Choose a song and a stage, and then build up your version of the song by selecting instruments for different parts. After you've played the parts that you wish to use to make up the song, select "Keep a Video." Create a CD cover for your song and press "Done" to complete your video.
Complete the "Rock Jam Mastery" lesson to unlock the accordion, bagpipe, cello, cowbell, DJ turntables, djembe drum, flute, galactic bass, guitar and piano, harmonica, harpsichord, Latin drums, reggae drums, shamisan, singer and timbales. Create four videos, and then you will be able to take the "Rock Jam Mastery" lesson, available under the "Jam Mastery" menu. After you've completed that lesson, the instruments will be unlocked.
Complete four more videos to unlock the "Expand Your Style" lessons. Completing your first "Expand Your Style" lesson will unlock the balled drums, beatboxer, black belt, clarinet, cuica, dulcimer, galactic congas, guiro, jaw harp, rapper, timpani and whistle instruments.
Play "The Legend of Zelda" theme tune in "Mii Maestro" mode to unlock the harp instrument. "Mii Maestro" mode is under the "Games" option on the menu, and the mode centers around conducting an orchestra. Move the Wii remote at the desired speed and level of intensity to control your animated Mii orchestra. You gain more points depending on the level of skill in your conducting.
Complete the first four levels of "Pitch Perfect" to unlock the NES horn instrument. "Pitch Perfect" is under the "Games" menu option, and is essentially a series of lessons designed to develop your musical ear and to teach you the basics of music theory. The tasks require you to be able to identify matching pitches, or put a series of notes in order from highest to lowest. As the lessons get harder, you will have to do things like create harmonies to match one produced by a speaker, or discern the highest pitched note out of a variety of different instruments. After you've completed the fourth lesson, you get the NES horn, which produces a classic Nintendo game music sound and the original "Super Mario Bros." theme song.