def mb_to_ms(mb, bytewidth, sample_rate_hz):
    """
    Convert MB of single channel WAV file to ms.
    """
    total_bytes   = mb * 1E6
    total_samples = total_bytes / bytewidth
    total_seconds = total_samples / sample_rate_hz
    total_ms      = total_seconds * 1E3
    return total_ms