[PD] matrix/array question

[folio.function.modification.implement at xoxy.net]

I have a  question about  how to use the matrix objects, I can print 
outputs and understand the basic maths like in the help patch but I 
am not sure what I would actually use a matrix for with audio.
Could someone give a link to show me a good use of the matrix objects.
I would also like to know if there is a simple way to dump the matrix 
values into an array.

One other question, I'm using the compiled OSX version of Pd and when 
I use the Pd.command the terminal window scrolls at a line per second 
even if there are no messages from Pd, how can I stop this?