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Sound level meters 1928 to 2012.pdf

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Page 1 of 34 Text & Figs Sound level meters AERC Sound level meters: 1928 to 2012 This article reviews the development of sound level meters, their principal electroacoustical performance characteristics, and the role of International Standards in the development of the instruments Prepared by Alan Marsh for publication in the J apanese Research J ournal on Aviation Environment Translated fromEnglish to J apanese by Ichiro Yamada and Chitose Nakamura 2012
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  Page 1  of 34  Text & Figs Sound level meters AERC Sound level meters: 1928 to 2012 This article reviews the development of sound level meters, their principal electroacoustical performance characteristics, and the role of International Standards in the development of the instruments Prepared by Alan Marsh for publication in the Japanese Research Journal on Aviation Environment Translated from English to Japanese by Ichiro Yamada and Chitose Nakamura 2012 March  Page 2  of 34  Text & Figs Sound level meters AERC Contents Introduction ................................................................................................................................................... 6   1928-1929: The first sound level meter (“noise” meter) ....................................................................... 6   Loudness .................................................................................................................................................... 6    Noise survey of 1928-1929..................................................................................................................... 7    Noise Survey Apparatus.......................................................................................................................... 7   Acoustical Society of America .............................................................................................................. 8   1930s............................................................................................................................................................... 8   World’s first standard for the performance of a sound level meter, Z24.3-1936 .......................... 8   Design characteristics.............................................................................................................................. 8   1940s to 1950s .............................................................................................................................................. 9   Z24.3-1944 ................................................................................................................................................ 9   Chicago Noise Survey of 1947 .............................................................................................................. 9   General Radio instruments ..................................................................................................................... 9   Rion sound meter ................................................................................................................................... 10   IEC and IEC Technical Committee 29 ............................................................................................... 10   1960s to 1990s ............................................................................................................................................ 10   IEC Publication 123............................................................................................................................... 10   Instruments of the 1960s ....................................................................................................................... 11   Standards of the 1970s .......................................................................................................................... 11   Instruments of the 1970s ....................................................................................................................... 12   What do we mean by time-weighted sound level?............................................................................ 12   Instruments of the 1980s ....................................................................................................................... 13   What do we mean by time-averaged sound level?............................................................................ 13   An integrating-averaging and integrating sound level meter of the 1980s ................................... 14   What do we mean by sound exposure level? ..................................................................................... 14   A multi-function sound level meter of the 1990s ............................................................................. 15   2000s to present .......................................................................................................................................... 15   IEC 61672, International Standard for sound level meters ............................................................. 15   Current versions of multi-function sound level meters conforming to IEC 61672-1.................. 15   What are key electroacoustical performance requirements in IEC 61672-1? .............................. 16   Concluding remarks ................................................................................................................................... 16   Acknowledgments ...................................................................................................................................... 17   References ................................................................................................................................................... 17    Page 3  of 34  Text & Figs Sound level meters AERC Figures   Figure 1 — Loudness “thermometer” scale with rankings for common sound sources. Scale, in “sensation units”, runs from the threshold of audibility at 0 units at the bottom of the scale to 108 units at the threshold of feeling. The rustle of leaves in a gentle breeze is shown at 10 units. Noise in an airplane is at about 96 units. Illustration is from an article by Wallace Waterfall in the “Engineering News Record” of 1929 January 10. ..........................................................18   Figure 2 — Truck and equipment used for survey of “noise” in New York City in 1929. Sign on side of truck reads: “Official Measuring Apparatus; Noise Abatement Commission.” Weight of the “noise meter” was in excess of 25 kg, including the batteries. .........................................................18   Figure 3 — Cover page of first Standard with design goals and tolerances for the electroacoustical performance of sound level meters. The Standard was sponsored for the  American Standards Association by the Acoustical Society of America (founded in 1929). The organizing meeting occurred in 1932 May for the committee that was established to draft a Standard. A draft Standard was discussed in 1934 May, revised, and approved by the  American Standards Association in 1936 February 17. The Z24.3-1936 Standard was published in the Journal of the Acoustical Society of America in 1936. ..................................................................19   Figure 4 — Sound level meter, octave-band filter set, and magnetic recorder as used for 1947 noise survey of Chicago; instruments were mounted in the back of a station wagon. ...........................20   Figure 5 — Portable hand-held sound level meter introduced by the General Radio Company (USA) as model 1551A in the early 1950s. Scale intervals are in decibel steps...................................20   Figure 6 — Illustration of recommended use of GR 1551A sound level meter. Instrument was supported by a strap held by the right hand with controls operated by the left hand.............................21   Figure 7 — GR model 1555A sound survey meter introduced in the mid 1950s. Logarithmically spaced markings on indicator dial for display of frequency-weighted sound level in decibels, but with variable resolution. ............................................................................................................................21   Figure 8 — Rion N1101 sound meter introduced in the 1950s. Display indicates frequency-weighted sound level in phons because of requirements as given in a German National Standard of 1942.......................................................................................................................................21   Figure 9 — Cover page for first international document issued in 1961 with recommendations for design goals and tolerances for the electroacoustical performance of general purpose sound level meters measuring frequency-weighted and time-weighted sound levels, International Recommendation IEC 123:1961...............................................................................................................22   Figure 10 — Model S.S.T.1 sound level meter from LEA in France introduced in the 1960s. Instrument was held by the handle and pointed at the source of sound with the display toward the observer; microphone was in the case opposite the display of sound levels in decibels. Logarithmically spaced markings on display............................................................................................23   Figure 11 — Design was by Peekel of Holland, but packaged and sold in the 1960s by Advance in England as model SPM1. No frequency weightings provided; instrument only measured octave-band sound pressure levels. Microphone was mounted on a short extension rod and was flush with the case when not in use. Pushing the button above the word “microphone” near the top left of the case released a spring that extended the microphone. Logarithmically spaced markings shown on the display. ...............................................................................................................23   Figure 12 — Rion NA-07 sound level meter (Japan) from the 1960s for measuring frequency-weighted sound level in phons; later modified to indicate sound levels in decibels. Toggle switch above display device to select F or S time weighting...................................................................24    Page 4  of 34  Text & Figs Sound level meters AERC Figure 13 — B&K model 2203 sound level meter (Denmark); weight about 3 kg (1960s). 25-mm-diameter capacitor microphone. Logarithmically spaced markings shown on the display. Time weightings F and S were provided. .................................................................................................24   Figure 14 — Cover page for International Standard issued in 1979 with design goals and tolerances for the electroacoustical performance of three classes of sound level meters for measurement of frequency-weighted and time-weighted sound levels, International Standard IEC 651:1979. ...........................................................................................................................................25   Figure 15 — Class 2 sound level meters from the 1970s: Cirrus 2.21 (England) and Rion NA-09 (Japan). Both indicated frequency-weighted sound level in decibels on a scale with logarithmically spaced markings. F or S time weightings were provided. The Cirrus 2.21 had a cavity on the left side of the upper case where the microphone on the gooseneck could be inserted. The cavity had a loudspeaker to produce a sound-pressure signal that could be used to check acoustical sensitivity because many customers refused to purchase a sound calibrator. ......26   Figure 16 — Integrating-averaging sound level meters from late 1980s. Left: Cesva SC-10 (Spain); right: Cirrus 2.22 (England). SC-10 only measured A-weighted sound levels. 2.22 measured A-weighted, C-weighted, or flat-weighted sound levels as time-averaged sound levels or as sound exposure levels. SC-10 has digital indicator scale; display for 2.22 has equally-spaced markings in decibels. Thickness of instrument set by diameter of AA batteries. Microphone and preamplifier relatively close to tapered case of instrument..........................................26   Figure 17 — Cover page for International Standard issued in 1985 with design goals and tolerances for the electroacoustical performance of three classes of sound level meters for measurement of frequency-weighted and time-averaged sound levels or frequency-weighted sound exposure levels, International Standard IEC 804:1985. ...............................................................27   Figure 18 — Multi-function B&K model 2231 class 1 sound level meter of the 1980s. 13-mm-diameter microphone and preamplifier mounted away from tapered case of instrument. Digital display for level of selected quantity. Instrument measures time-averaged sound levels; F or S time-weighted sound levels, maximum time-weighted sound level in a time period, and sound exposure levels, all with choice of frequency weightings A, C, or flat. ...................................................28   Figure 19 — Multi-function B&K model 2260 class 1 sound level meter introduced in the 1990s. Long tapered case minimizes effect of sound reflected from case to microphone and helps to conform to directional response requirements of international performance standards. 13-mm-diameter capacitor microphone and preamplifier. Screen can display a spectrum of one-third-octave-band sound pressure levels with or without frequency weighting. ..............................................28   Figure 20 — Cover page for International Standard IEC 61672-1 issued by the International Electrotechnical Commission in 2002 May with electroacoustical performance specifications for class 1 and class 2 sound level meters measuring frequency-weighted and time-weighted sound levels, frequency-weighted and time-averaged sound levels, and frequency-weighted sound exposure levels. ........................................................................................................................................29   Figure 21 — Modern designs for multi-function class 1 sound level meters–Larson Davis model 831 (Provo, Utah, USA on left); Quest Technologies/3M model SoundPro (Oconomowoc, Wisconsin, USA on right). .........................................................................................................................30   Figure 22 — Modern designs for multi-function class 1 sound level meters: Cirrus Research model 171B Optimus (North Yorkshire, England on left); Svantek model Svan 979 (Warsaw, Poland on right).........................................................................................................................................30   Figure 23 — Modern designs for multi-function class 1 sound level meters: Cesva model SC 310 (Barcelona, Spain on left); Rion model NL-62 (Tokyo, Japan on right). ..........................................31   Figure 24 — Modern-designs for multi-function class 1 sound level meters: Norsonic model Nor 140 (Oslo, Norway on left); B&K model 2270 (Naerum, Denmark on right). ..........................................31  
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