Reverberation Time

trying to design a T60 measurement function. I think i've worked it out but every time i run the function it crashes Matlab. I must have an infinite loop or using a very inefficient way of calculating the t60 but i can't see why it's not working. Any help would be much appreciated thank you

 function [ T60Plot ] = T60Plot(input,Fs)
  %UNTITLED3 Summary of this function goes here
  %   Detailed explanation goes here

modInput=sqrt(input.^2);
L=length(input);
maxA = cumsum(modInput);
invertModInput = modInput';

for n = 1:L; n1 = 0;
    if 20*log10(sum(modInput(n:L))./maxA)<=-60;
        n1 = n1;
    else
        n1 = n1+1;
    end
end
T60Plot = n1/Fs;
end

[Walter Roberson]

Do not use the same output variable name as your function name.

Answer 1

[Daniel Shub]

There are already a three implementations FEX: t60

[Sam]

Yes there are but i've already tried one to understand it and it didn't work. One is far too complicated for me to understand. I'm also supposed to write the code myself. I would rather like to use the original stuff above.

Answer 2

[Walter Roberson]

You set n1 to 0 each iteration through the "for" loop. The "n1" after the iteration of a loop is thus always going to be 0 or 1. Then you go on to the next iteration, overwriting n1. The result would be the same as if your "for" went from L:L instead of 1:L .