Using a base value of 1 for radius

Unable to figure out weird bug with `Math.random()` causing odd canvas
artifacts when radius is 0, so adding 1 to the radius value at all
times.
Reduced fftSize to 512 and using more song data

Reduced fftSize to 512 in order to get smaller input. Also using a
second radius size for the second canvas in order to get more song data
on the screen and vary the green/purple a bit.