Nowadays smartphones became an important part of our life. The appearance of these devices made as huge impact in our world as the spreading of PC-s in the 1990’s, and if we look at the trend, we can clearly see that our phones are taking roles from personal computers and other devices, such as GPS, video game consoles and cameras. Now we can use smartphones for browsing, e-mailing, navigation or multimedia purposes. As technology evolves, those functions are getting better and better, so these days, smartphones have become the tools of professional photographers, video makers or musicians.
The topic of this thesis is about musical tuning technology from the area of audio signal processing. My goal was developing a tuner-software on Android, which is one of the most popular smartphone operating systems next to iOS and Windows Phone. The application includes two main functions. One is a chromatic tuner, which can detect the frequency of a sound that was read by the microphone. The other is a polyphonic tuner which helps guitar players to make a quick string check.
To create this application, I had to make some research about the theory of musical signals. I used MATLAB for examining the most often used time domain and frequency domain based algorithms regarding on accuracy and speed. At the last section of my research, I picked the two best algorithms for chromatic and polyphonic tuning.
Furthermore, I gathered information about the Android system and Java programming language regarding their capability of audio signal processing.
After development, I tested the software with different instruments and frequencies, and compared it with other tuner applications which are available in Google Play.