The 1/12th octave mode option allows the user to shift the DS analyzer to a higher frequency resolution. Higher resolution is used to set crossovers or analyze frequency or standing waves. The higher resolution also provides the information necessary to use parametric equalizers and other types of notch filters.       Frequency Ranges: DS 1/3rd Octave Standard - 20Hz to 20kHz
                               1/12th Octave Low - 27Hz to 141Hz
                              1/12th Octave High - 150Hz to 794Hz     Option Kit Contains: Upgraded EPROM device.