Scrolling Data

hello guys
i try my self in some envelope analysis
my goal is to send a bang each time when there is a minimmum of loudness.
right now this how its build up

my idea was now to to store 3 afterwards incoming values from the peakamp object on to three positions and 1 2 3. the values arrive at position one . when the next value comes, position one goes to position 2 and the new on position one.
woth the next 2 on 3; 1 on 2 and new on one and so on..

is there an object that can sore values in that way?
guess ive seen one some days ago but no idea whats the name

would then compare the value on position two with the values on position 1 and 3
and if its lower then both than bang them as an minimum point.

do you think this way is to instable in praxis?
cheers