This function converts the WAV files stored in a folder to WAV using a different sampling freq and number of channels.
    ARGUMENTS:
     - dirName:     the path of the folder where the WAVs are stored
     - Fs:          the sampling rate of the generated WAV files
     - nC:          the number of channesl of the generated WAV files

def convertFsDirWavToWav(dirName, Fs, nC):
    '''
    This function converts the WAV files stored in a folder to WAV using a different sampling freq and number of channels.
    ARGUMENTS:
     - dirName:     the path of the folder where the WAVs are stored
     - Fs:          the sampling rate of the generated WAV files
     - nC:          the number of channesl of the generated WAV files
    '''

    types = (dirName+os.sep+'*.wav',) # the tuple of file types
    filesToProcess = []

    for files in types:
        filesToProcess.extend(glob.glob(files))     

    newDir = dirName + os.sep + "Fs" + str(Fs) + "_" + "NC"+str(nC)
    if os.path.exists(newDir) and newDir!=".":
        shutil.rmtree(newDir)   
    os.makedirs(newDir) 

    for f in filesToProcess:    
        _, wavFileName = ntpath.split(f)    
        command = "avconv -i \"" + f + "\" -ar " +str(Fs) + " -ac " + str(nC) + " \"" + newDir + os.sep + wavFileName + "\"";
        print(command)
        os.system(command)