Hi there, I was wondering if someone could recommend a cool plug-in or technique for achieving the background effect in this image:

Ideally i’d like to create some kind of gradient background, and apply the effect on top. The effect at the very least would give it the ‘pop art’ type look seen above. And ideally, it would even have some form of animation on the actual effect itself. (such as the circles enlarging / shrinking)
Also, as another question - linked to the same project; how could I have a compositions scale attribute driven by sound most easilly?
Thanks for all your help, and I’ll share the final effect with you once it’s all done!