Audio on video is very important.
Music, speech and effects all have a part in the production of good video.
Choosing and creating the right music and sounds will ultimately leave an impression on the target audience.
As it is such an emotive element, I explore, experiment and rely on instinct to compose my own music and I strive to maximise the desired effects.
You can listen to examples of compositions I have used with my short films by following this Soundcloud link:
Below is an example of how music and sound improves the impact of a video.