cataRT live updating

I am trying to find a way to constantly update cataRT so that the sounds plotted on the lcd are, say, the last 20 seconds chopped up into quarter of a second samples (for example). Any ideas on how I could do this, or if this is even possible? I can't even figure out a way to use a buffer~ as the sound file analyzed--I can only seem to use .aiffs already saved to disk.