Selecting highest (or average) in a range of numbers over a set period.

I have a MSP patch reading Db from a single mic. This is running alongside a counter that plays a simple four note tune every four seconds (1st note on the first second, 2nd note on the second second etc). The counter stops and resets after a few minutes.

Then I have 6 presets for different synths from which the simple tune can be played.

I want the Db level to determine which synth is selected. The louder the mic input, the more chaotic the synth sound selected.

Essentially, the result should be a patch that allows a theater performer with a microphone to have the "score" react to the performer's volume. i.e quiet speaking triggers soft melodic music, shouting triggers distorted disharmonious sounds.

I currently have a series of gates with "if" statements. The gates only open when the 4 second tune has finished one cycle (4 seconds) then, the Db that I happen to be inputting at that exact moment triggers the corresponding synth and closes the gate for another four seconds.

Problem is:

If the opening of the gate happens to correspond with a breath between two loud shouts, the first Db reading taken will be low and so the gate series will select an inappropriate synth from the presets.

So:

Can anyone recomend a way in which to average a series of numbers flickering in a number object over a period of time (say four seconds)?

or...

Perhaps I would be better off taking the highest number from the four second period and using that for the selection and if so, how?

Cheers,

ND