... of short duration can form spectrum analyzer with external filterfrequency range : 10HZ-20KHZbasic configuration: main machine, microphone, fan ... , briefcase, filter(optional) Modal TL5660 seriesMeasuring range TL5660A: 30dB-138dB(A),40dB-138dB(C),45dB-138dB(linearity)TL5660B(low ... 40dB-135dB(linearity)TL5660B(high level): 55dB-165dB(A),65dB-165dB(C),70dB-165dB(linearity)Frequency range10Hz- ...