1. © Oxford University Press 2009 11.5b Harmonics A tuning fork produces a note with only one frequency. The shape of the wave on the oscilloscope is very smooth.

2. © Oxford University Press 2009 Instruments produce notes of more than one frequency. The main note produced is called the fundamental. But other notes are produced at the same time. These are called harmonics. These different notes add together to make the sound that is unique to that instrument. We call this sound its timbre. 11.5b Harmonics

3. © Oxford University Press 2009 The frequency of the harmonics may be twice, three times, four times or even more times the fundamental frequency. 11.5b Harmonics

4. © Oxford University Press 2009 All these frequencies together make up the note. The bottom line here shows the wave pattern formed by the fundamental and harmonic frequencies when the note is played on the instrument. 11.5b Harmonics

5. © Oxford University Press 2009 These traces show the wave patterns of the same note (middle C) when played on different instruments. This is what makes them all sound different even when they are playing the same note. saxophoneviolin clarinet 11.5b Harmonics

6. © Oxford University Press 2009 Your voice is just the same – everyone has their own unique timbre. 11.5b Harmonics