價格：免費
更新日期：2018-01-21
檔案大小：599k
目前版本：0.4
版本需求：Android 2.1 以上版本
官方網站：mailto:stellphone4@gmail.com
A lesson on the chromatic scale where each note is calculated using a mathematical formula. A440 or A4 (also known as the Stuttgart pitch), has a frequency of 440 Hz, which is the musical note of A above middle C.
