write the echoSound function that takes an input sound and returns a new sound with an added echo. to add an echo to a sound, add on another, lower-volume copy of that sound starting 5000 samples after the end of the first original sound. the lower volume copy of the sound should be at 25% of the original volume. The number of samples in your new sound will be 2x(sum of the number of samples in the original sound) plus 5000 samples. In general your new y data array of sound should be: -original sound -5000 samples of silence -reduced volume of original sound.

function[y,f] = echoSound(filename)

in matlab