Conventional spectrum analysis is used to measure a system’s frequency response and consists of a pink noise generator covering the entire audio spectrum with a third-octave filter which sweeps from 20Hz to 29kHz.
The Sound Check response analyzer uses individually recorded third-octave bands on CD which are read by an integral sound pressure level meter calibrated in 3dB steps from -15dB to +12dB with a central green 0dB reference indication. This forms a quick and simple method of ascertaining frequency response where the clinical accuracy of expensive laboratory equipment is not required.
Most sound level meters are “weighted” or have a response curve tailored to approximate the human ear’s response. The Sound Check analyzer uses an electret capacitor omnidirectional microphone with manufacturer’s response of 20Hz – 20kHz +-2dB. Therefore it is essentially flat allowing for the deficiencies in LED type meters. As “C” weighting is usually used for measuring music, Sound Check’s meter is calibrated to read approximately 80dBC at the 0dB reference point.
The third-octave bands are warbled (modulated) to eliminate room standing waves which could cause false readings and the meter is averaged to provide steadier readings at low frequencies.