def mel2hz(mel):
    """Convert a value in Mels to Hertz

    :param mel: a value in Mels. This can also be a numpy array, conversion proceeds element-wise.
    :returns: a value in Hertz. If an array was passed in, an identical sized array is returned.
    """
    return 700 * (10 ** (mel / 2595.0) - 1)
