[maxmsp] (help) Find the max amplitude in an fftin~ analysis

Hi to all, i spend a lot of time try to find how to extract the  frequency with the maximum amplitude from a fft~ analysis.
I try with comparator like >~, snapshot~ change~ and edge~ but nothing want work. I just want to make an pfft~ (inside a poly~ for have a good downsample of the patch) and inside the pfft~ i need to extract the frequency values (better if in float format) with an amplitude threshold that i want.

Maybe i don't understand want came out of the fftin~ object: maybe for this work i can make a mxj java object that take a pair of (fftin~ real, fftin~ sync) signals, read the values and save and output the values if they are over a threshold.
Please can some one also tellme what exactly came out of the fftin~ object? it can be interpretated as a normal signal, of a block of values.
 
Thanks for all your helps