Abstract
The researches have revealed how beginning pianists can analyze their performance quality by using the software which is called metronome, players record their melodies with the cell phone software. At the end of piano playing, the software will show a score that tell pianist weather this piano playing is terrific or hideous. The main idea of our researches is to make the grading system in this software as correctly as possible. As well as recording the performance, players can hear the beat transmit from cell phone. There are 14 seconds only in each audio data, the former quarter of tempo should be blank without piano sounds. There are four steps to accomplish the grading system: the first one is by utilizing Fast Fourier Transform to capture the power distribution of spectrum gathering from clear metronome tick. Secondly is to establish the threshold choosing the frequency bin, whose energy exceed the threshold, tempted to eliminate. Third one is to use onset detection sensing the moment when piano button is pressed. The last one is to calculate the timing difference between metronome tick form cell phone and piano onset, furthermore, translate it to points. As a consequence, our first experiment may show the audio data score distribution from our grading system. Second experiment will do the error analysis toward deleting frequency bin. Experiment three and four try to accommodate amplitude of the deleted tick as well as do the error analysis. Our final experiment will optimize all the parameters to make accurate grading system possible. After numerous times of error analysis and parameters regulation, average error has decreased from 34.66 to 20.71 since the first experiment. Apart from that, trend of data distribution is reasonable, we are able to confirm the grading system is beneficial to those pianists who are beginners.