#NEWLINE# def lower_frequency( frequency = None , fraction = 1 , n = None , ref = REFERENCE ) : #NEWLINE# #INDENT# 'Lower band-edge frequency.\n    \n    :param frequency: Frequency within the band.\n    :param fraction: Band designator.\n    :param n: Index of band.\n    :param ref: Reference frequency.\n    :returns: Lower band-edge frequency for the given frequency or band index.\n    \n    .. seealso:: :func:`acoustics.standards.iec_61260_1_2014.exact_center_frequency`\n    .. seealso:: :func:`acoustics.standards.iec_61260_1_2014.lower_frequency`\n    \n    ' #NEWLINE# center = exact_center_frequency ( frequency , fraction , n , ref = ref ) #NEWLINE# return acoustics . standards . iec_61260_1_2014 . lower_frequency ( center , fraction )