remove frequency component above 5Khz

How to write MATLAB program to remove frequency component above 5Khz fro the audio file.

   1. Use standard matlab function for filter
   2.Implement overlap-add/save method with the help DFT to implement above operation.

I recorded 3 sec audio file and filtered it, using butterworth filter. After that I want to determine DFT of recorded signal using overlap-add or overlap-save method. But I don't understand how to segment the audio signal and which signal should be used as impulse sequence for calculation of DFT and how to implement DFT Audio signal. please help me its urgent....

[Walter Roberson]

http://www.mathworks.com/matlabcentral/answers/29922-why-your-question-is-not-urgent-or-an-emergency