This instrument is the SA2703, an octave band filter manufactured by Kobayasi Institute of Physical Research in 1959.At the time, as a device ancillary to sound level meters, it was marketed as a band filter.To determine the characteristics of a measured sound, both frequency characteristics and sound pressure (loudness of sound) must be analyzed. Sound is a combination of various frequency components. Once the frequency characteristics (as a waveform) are known, we can estimate the source of the noise and find a method for controlling it. Today’s sound level meters can be held in one hand, and octave band analysis can be performed easily by installing an analysis program on the sound level meter. But 70 years ago, devices like this were required to determine frequency characteristics.Courtesy of the Museum for the Science of Sound, Kobayasi Institute of Physical ResearchPhoto by Yuki AkabaOctave band filterOwned by the Museum for the Science of Sound, Kobayasi Institute of Physical ResearchThe Evolving World of Acoustics and Vibration TechnologiesThe World of Acoustics
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