The sense of sound, so called absolute and relative pitch, influences our perception and understanding of music. This research aims to extend the human sense of pitch in a multimodal approach using computers. In this paper, we focus on absolute pitch. Absolute pitch is an ability that some people are said to acquire by the age of six. Although degrees of this ability vary, people who have this ability are generally said to be able to recognize the note names even without being given a reference note. This is a potentially useful ability for understanding music, although it is difficult to acquire this ability through training as an adult. In this paper, we present the results of a subjective survey regarding with sound perception conducted on absolute pitch holders, the design and implementation of Otonona, a system for accessing the usefulness of absolute pitch using multimodal augmented reality, and future work.