Analysis Of Instruments Sounds

In a song, is usual to have many instruments playing at the same time. Each instrument has different characteristics and produce its own type of wave. In order to figure out how to identify if is only vocal or song, it is useful to analyze the waves from different instruments

On the picture above, It is showed the waves produced when the note ”C” is played in different instruments.

It is important to highlight that the waves of wind instruments starts with low intensity and then increase. This occurs because these instruments depend on the displacement of sound caused by the musician, so this short period of time is when the user adjust the sound that is wanted. On strings instruments, the sound is produced instantaneously.

If we look closely, we can see, in details, how these waves move:

With these waves, it is possible to analyze the behaviour of each instrument and then classify them. In this way, we can see an audio and identify the presence of some of them.

The main purpose of this project is to differentiate music from speech, so it`s necessary to look closely to the differences of these waves:

The first wave is a simple song, in this case, it was used a song that does not have many effects in order to facilitate the visualization of the wave. The second wave is a voice sample of a person speaking.

The first thing that is easily noticed is that the song has some waves with higher intensity that are periodic, and these waves are produced by the snare drums. So, this pattern is a good characteristic to identify a song.

Besides, the pitch is another features that differs songs from speech. As is seen on the picture the voice has difficult to maintain the pitch, and varies along the time continuously; however, the song can keep the pitch for a longer time