MusicToolbox helps music professionals and students by providing the most needed instruments for daily practice in a single app: metronome, musical tuner, audio record/playback and waveform/spectrum analyzer. The metronome and tuner perform with the highest accuracy possible, while the sound recorder can record music and play back immediately without leaving the app. The waveform/spectrum analyzer allows users to "see" the sound they are producing for analysis of such things as sound attack/decay patterns and harmonic overtones. All these instruments run simultaneously in MusicToolbox.