A lot of music theory is about limiting which notes to use in your song to a small set that sound good together. The earliest set of such notes was called the Pentatonic Scale. It has five notes and looks like this:
Click the circles to play the notes.
Lets look at each of these notes and their waveforms.
One of the most important things to understand is that the notes themselves aren't important. You could start the pentatonic scale on any frequency. In this case, Note 1 has a frequency of 200Hz, but it could be any other number as well.
What is important is the ratio the other notes have with Note 1. Lets take a look.
For Note 4 we have a very simple ratio of 3:2. That is, for every two waves of Note 1 (200Hz) there are three of Note 4 (300Hz). Click play to hear how nice they sound together.
The next ratio used is 5:4. Note 3 has a frequency of 250Hz. You can see that for every four waves of Note 1 there are five of the Note 3.
The next ratio used is 5:3 to give us 333.3Hz. You can see that for every three waves of Note 1 there are five of Note 5.
Lastly is Note 2 with a ratio of 9:8 (225Hz). You can see that for every eight of Note 1 there are nine of Note 2.
You might have noticed that this ratio isn't as simple and therefore these two notes don't sound as nice together as some of the previous notes.
Finally, lets find a pair of notes with the simplest ratio, 2:1. This is known as an Octave and is not considered a new note. An Octave is the same note with a higher pitch. In this case 400Hz and 200Hz.
A more robust and flexible system you've probably used before.Next Lesson »