1. An Android Application to Evaluate Piano Playing Using Fast Fourier Transform (FFT) Algorithm
Green Mandias1, Andria Wahyudi2, Hendriawan Jumawan3 and Raissa Camilla4
1,2,3,4Faculty of Computer Science Universitas Klabat Manado, Indonesia

2. Backgroud
The mobile device application development in general had a positive impact in many areas, one in the field of music
At the beginning of the 18th century, the instrument evolved into a musical instrument called the piano [3].
The person who plays the piano called pianist, A trained pianist to have some expertise, namely ear training, rhythm training, improvisation, technique, memorization and sight reading [4].

3. Expertise sight reading is the ability to read music tablatures which include the ability to read music symbols, the implementation of harmony, melody and beats
Sight reading is a process that runs automatically to musicians who have trained. Sight reading is something quite difficult to learn and require training process long enough to have skills in reading music notation [5].
Researchers observed that the lack of expertise sight reading can cause errors such as tempo, tone, dynamics that are not right in the game piano.

4. In accordance with the above explanation, the researchers saw the opportunity to evaluate the piano playing, especially in improving the ability of sight reading so it can lessen the errors in determining the tone, tempo and dynamics by creating an Android application to evaluate the piano playing using Fast Fourier Transform (FFT) algorithm

5. Application Framework
Figure 2 explains how this application works. The first step is we chose the partitures that will be used in the application to make the original songs and then we put it into the application as WAV. The third step until the last step would explain how the user access this application. The user has to set up the smartphone that will be used for the application and then the user will be playing the song using piano that has been chose before as the user open the application. It will produce a sound that will be recorded by the application and inside the application, the FFT algorithm is running the process to convert the sound into WAV to be compared using FFT algorithm. And the last step the application will show the comparison result to the user between the original song and the song that has been recorded by the user by playing the piano in the form of percentage.

6. The Application
Figure 3 shows the main menu view of the application. Here are the explanation of the numbers in Figure 3:
The main menu to start the piano evaluation
The menu that shows the results of previous evaluations
Help menu that explains how to use the application
The menu shows information about the app makers who evaluate piano
Menu for listening to songs and download files tablatures piano of available songs.
These are the images of how this application look like, the user interface of application.

7. List Song Display & Record Display

8. Result Display

9. RESULTS

11. DISCUSSION AND OPEN ISSUES
There are 3 issues and our suggestions we would like share for future work. This application is only made for Android user, therefore it would be great if this application can also run in another Operating System too, such as iOS and Windows phone. The second issue is this application is limited in songs, it might be working better if the user can add their own songs and this application could automatically transform it into WAV file. And the last issue and the most important one is we found out that it will not be an effective way to evaluate something without telling the mistakes that need to be fixed. For future work this application would be perfect if the comparing result could display the mistakes that includes the wrong notes, the tempo and the dynamics in the form of a percentage of quantitatively.

12. CONCLUSION
Based on this research there are 4 points of conclusion. The first point is this application can run on Android devices with Android 5.0 (Lollipop) as the minimum requirement for Android version. We also concluded that this application is successfully obtained its main work which is to display the comparison result between the original piano song and the piano playing recording. So in other words, this application can be used to do an evaluation for piano. The third point is the consistency for an evaluation is lacking, except if we play the right notes according to the piano partiture the score will always be perfect. And for the last point, we got an interesting result. We’ve tried to play the piano perfectly in a room full of noise, and the score that came out was 100%. Based on this result, we summed up that the process of comparing from this application only compare the major sound of the recording, so it won’t affect the score if there were noise around.