3

Frequency resolution

Third -octave bands

Third -octave bands

Each octave band can be divided into three adjacent bands called third- octave band. Because of the logarithmic relationship between adjacent bands, the center frequencies of third-octave bands differ from each other by 26%. For example, the center frequency of the next third-octave band above the 1000 Hz third-octave band is at 1260 Hz. Figure 1-3 is similar to Figure 1- 2 but shows the thirty-three third-octave bands in relation to the instrument’s bandwidth.

Level

Figure 1-3: Third Octave bands

Naming bands

Bands are conventionally named for their center frequencies in accordance with acoustical industry standards. Table 1-1 identifies the SoundPro SE or DL models that have octave and third-octave bands option with their exact center frequencies and their corresponding standardized names.

Models SE and DL

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3M SE, DL user manual Third -octave bands, Naming bands