reverse FFT

[inadaze]

Hi,
I am using matlab.
I was wondering if anyone knew how to take the results from a spectrum analysis of a signal in x at sample frequency fs:
y = abs(fft(x,fs));
and turn it back into the signal x. My purpose is to modify the spectrum by removing certain frequencies found in the spectrum analysis and then turning it back into a signal to hear what it sounds like.

Thanks
Jay

[Dr Transport]

apply the filter, then retransform.