Think of it like this...the resistors represent a tap filling up a bucket.
The bucket stores water until it is needed and the bucket can empty
very fast, much faster than the tap that is filling it. As long as the tap
can refill the bucket between uses it will never run out.
The resistors are chosen based on the average draw of the op amp
you are using. Using resistor values too high just wastes power from
your battery. You want the value to be as small as possible and still
have enough power for your op amp. The Capacitor store energy
so the op amp can provide bursts of energy for things like drum
hits and bass notes. Bigger caps provide more energy for a longer
time.
That was a pretty non-techinical explanation but I hope it helped...
