Music is usually broken down into melody, rhythm and harmony. But what about the very lowest notes in music, that can have an impact on all three? In this film Howard looks at the abiding fascination musicians and composers have had with the bass.

For half a millennium instrument makers have been trying to construct instruments of all shapes and sizes capable of thudding, sonorous low notes. Only with the arrival of the synthesizer did they succeed in producing a rival to the mighty organ. With disco, dance, and drum 'n' bass, the bass has arrived centre stage.

But bass notes have another, crucial role. Far from just plodding away in the background, bass lines can have a critical effect on the whole structure of a piece of music, helping to drive the chord progressions.