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Rion NL-42 Technical Notes

Other manuals for NL-42: Instruction Manual
Manual is about: sound level meter

Summary of NL-42

  • Page 1

    3-20-41 higashimotomachi, kokubunji, tokyo 185-8533, japan http://www.Rion.Co.Jp/english/ technical notes sound level meter nl-42 / nl-52.

  • Page 3

    I organization of the nl-42/nl-52 documentation documentation for the sound level meter nl-42/nl-52 comes in three parts, as listed below. Instruction manual describes operating procedures for the sound level meter nl-42/nl-52, connection and use of peripheral equipment such as a level recorder and ...

  • Page 4

    Ii contents organization of the nl-42/nl-52 documentation .......................... I microphone .....................................................................................1 construction and operation principle .........................................1 thermal characteristics ..............

  • Page 5

    Iii the greatest susceptibility confi guration for radio frequency fi elds ...............................................................36 statement of conforming to the basic statement ......................36 adjustment data for sound calibrator .......................................37 the lowe...

  • Page 6

    Iv.

  • Page 7: Microphone

    1 microphone measurements of sound pressure level can be carried out with a variety of microphone types. The sound level meter nl-52 employs the prepolarized condenser microphone uc-59 (nl-42 employs uc-52) that is compact and delivers stable and reliable response. Construction and operation princip...

  • Page 8: Thermal Characteristics

    2 microphone thermal characteristics the thermal characteristics of a microphone indicate how sensitivity changes at various temperatures. The diagrams below show the thermal characteristics of the microphone uc-59 and uc-52. Temperature (°c) thermal characteristics of uc-59 (at 250 hz) response (db...

  • Page 9: Humidity Characteristics

    3 microphone humidity characteristics the humidity characteristics of a microphone indicate how sensitivity changes at various humidity levels. The diagrams below show the microphone uc-59 and uc-52. Relative humidity (%) humidity characteristics of uc-59 (at 250 hz) response (d b ) -0.5 -0.4 -0.3 -...

  • Page 10

    4 microphone specifi cations of microphone uc-59 model: uc-59 nominal diameter: 1/2 inch sensitivity: -27 db ±2 db (re. 1 v/pa)* frequency response: 10 to 20000 hz capacitance: 13 pf ±1.5 pf temperature dependent sensitivity level fl uctuation: ±0.35 db max. From -10 to +50ºc referenced to 23ºc (at ...

  • Page 11

    5 microphone specifi cations of microphone uc-52 model: uc-52 nominal diameter: 1/2 inch sensitivity: -33 db (re. 1 v/pa)* frequency response: 20 to 8000 hz capacitance: 19 pf diaphragm type: titan alloy fi lm temperature coeffi cient: -0.008 db / ºc (at 250 hz) humidity-dependent sensitivity change...

  • Page 12: Preamplifi Er

    6 preamplifi er preamplifi er requirement since the condenser microphone is a small-capacity transducer, it has high impedance, especially at low frequencies. Therefore a very high load resis- tance is required to ensure uniform response extending to the low frequency range. The relationship between...

  • Page 13

    7 infl uence of microphone extension cable when the output of the microphone/preamplifi er is routed through an exten- sion cable, certain limitations regarding measurable sound pressure level and frequency range will apply. This is due to the infl uence of the cable capaci- tance. The longer the ca...

  • Page 14

    8 frequency weighting network the nl-42/nl-52 provides frequency weightings a, c and z. The electri- cal characteristics of the weighting network at ac output connector are as shown below. The volume impression (loudness) of a sound depends not only on the sound pressure level, but also on the frequ...

  • Page 15

    9 rms detection circuit and time weighting the sound level meter uses rms detection. The rms value e (rms) is defi ned by the following equation. The voltage e which changes over time is raised to the second power, and integration for the time interval t is performed. The result is divided by t and ...

  • Page 16

    10 rms detection circuit and time weighting during sound level measurements, the level often fl uctuates drastically, which would make it diffi cult to evaluate readings if some kind of averaging is not applied. Sound level meters therefore provide the capability for index weighting (index averaging...

  • Page 17

    11 rms detection circuit and time weighting time weightings and time constant f (fast) s (slow) i (impulse) 125 msec 1 s 35 msec 125 msec 1 s 1.5 sec time weighting time constant rise time decay time the time weighting network of the sound level meter performs index averaging on the square of the so...

  • Page 18: Measurement Functions

    12 measurement functions l aeq (equivalent continuous sound level) for a sound pressure level signal that changes over time, the l aeq (equivalent continuous sound level) is a hypothetical constant sound pressure level that has the same energy as the actually measured signal in the measurement inter...

  • Page 19: (Sound Exposure Level)

    13 measurement functions l ae (sound exposure level) the l ae (sound exposure level) is a hypothetical constant 1-second sound pressure level having the same energy as a single-event sound pressure level measured with a weighting. It is determined by the following equation. L 10 log 10 t 2 t 1 ( t) ...

  • Page 20: (Percentile Sound Level)

    14 measurement functions l n (percentile sound level) the l n (percentile sound level) is the sound level which was n percent or more of the measurement time. The nl-42/nl-52 allows the user to select fi ve values for n (from 1 to 99, in 1 steps). The sampling interval for l n processing is 100 ms (...

  • Page 21: (Takt-Max Sound Level)

    15 measurement functions l atm5 (takt-max sound level) for the duration of the measurement, the maximum level within a 5-second interval is sampled and the power average is determined. L atm is calculated according to the following equation. L m : maximum level within interval (5 seconds) n: number ...

  • Page 22

    16 infl uence of background noise when measuring a certain sound in a certain location, all other sounds present at that location except the measurement target sound are background noise (also called ambient noise or dark noise). Since the sound level meter will display the combination of target sou...

  • Page 23: Description For Iec 61672-1

    17 description for iec 61672-1 standard paragraph description see also remark nl-52 nl-42 4 reference environmental conditions 9.1 ambient temperature: 23°c static pressure: 101.325 kpa relative humidity:50% ambient temperature: 23°c static pressure: 101.325 kpa relative humidity:50% 5 performance s...

  • Page 24

    18 description for iec 61672-1 standard paragraph description see also remark nl-52 nl-42 5.1.16 highest spl and peak- peak input voltage without causing damage. 9.3 i) 148 db 11 vp-p 150 db 11 vp-p 5.1.17 characteristics of each in- dependent channel to be described n/a n/a 5.1.18 initial time inte...

  • Page 25

    19 description for iec 61672-1 standard paragraph description see also remark nl-52 nl-42 5.5.11 how to test level linearity if display range ity range 9.3 k) n/a n/a 5.6 self generated noise 5.6.1 self-noise at the more sensitive ranges (includ- ing microphone) 9.2.5 o) 9.3 h) maximum value a: c: z...

  • Page 26

    20 description for iec 61672-1 standard paragraph description see also remark nl-52 nl-42 5.15.4 description of the dis- played quantities 9.2.2 a) n/a n/a 5.15.5 statement of the display update rate 9.2.2 g) 1 second 1 second 5.15.6 time interval for comple- tion of the integration 9.2.5 f) less th...

  • Page 27

    21 description for iec 61672-1 standard paragraph description see also remark nl-52 nl-42 5.18.2 operating mode or high- est radio frequency emis- sions 9.3 n) operation mode: normal operation connection pattern: ac adapter nc-98 output cable cc-24 communication cable cc-42r usb cable (with ferrite ...

  • Page 28

    22 description for iec 61672-1 standard paragraph description see also remark nl-52 nl-42 6.6.4 (note) field strength for conform- ing (in case > 10 v/m) 9.3 m) n/a n/a 7 provisions for use with auxiliary devices 7.1 correction for use of mi- crophone cable 9.2.6 b) n/a n/a 7.2 effect of optional ac...

  • Page 29

    23 description for iec 61672-1 standard paragraph description see also remark nl-52 nl-42 9.2.2 g) description of the display and update rates 5.15. 2 - 3-4-5 refer to 5.15.2-3-4-5 refer to 5.15.2-3-4-5 9.2.2 h) total range of a- weighted spl (@ 1 khz) 5.1.12 refer to 5.1.12 refer to 5.1.12 9.2.2 i)...

  • Page 30

    24 description for iec 61672-1 standard paragraph description see also remark nl-52 nl-42 9.2.5 b) procedure to measure sound, infl uence of the instrument case and operator. 5.1.6 5.2.4 5.2.5 refer to 5.1.6 refer to 5.2.4 refer to 5.2.5 refer to 5.1.6 refer to 5.2.4 refer to 5.2.5 9.2.5 c) recommen...

  • Page 31

    25 description for iec 61672-1 standard paragraph description see also remark nl-52 nl-42 9.2.6 b) corrections for microphone cable 7.1 refer to 7.1 refer to 7.1 9.2.6 c) use of bandpass fi lters 7.4 refer to 7.4 refer to 7.4 9.2.6 d) connection of auxiliary devices 7.5 refer to 7.5 refer to 7.5 9.2...

  • Page 32

    26 description for iec 61672-1 standard paragraph description see also remark nl-52 nl-42 9.3 j) maximum and minimum power supply voltage 5.20.2 refer to 5.20.2 refer to 5.20.2 9.3 k) how to test level linearity if display range ity range 5.5.11 refer to 5.5.11 refer to 5.5.11 9.3 l) time interval f...

  • Page 33

    27 description for iec 61672-1 iec 61672-1 (jis c 1509-1) frequency response tab. 1 iec 61672-1 (jis c 1509-1) frequency response nominal frequency (hz) exact frequency (hz) uc-59 frequency response (db) uc-52 frequency response (db) nl-42/52 frequency response (db) nl-42/52 electrical response (db)...

  • Page 34: Position

    28 description for iec 61672-1 reference incidence direction and reference point position fig. 1 reference incidence direction and reference point position reference direction of incidence reference point position center of diaphragm plane.

  • Page 35: Frequency Response

    29 description for iec 61672-1 frequency response the frequency response of a sound fi eld microphone is expressed as the fre- quency response in the reference direction of incidence (0º). The diagram below shows an example for the frequency response of the microphone uc-59 and uc-52. Fig. 2 frequen...

  • Page 36

    30 description for iec 61672-1 infl uence of body refl ection the nl-52/nl-42 is designed to minimize refl ections caused by the body of the unit. The chart below shows the infl uence on the measurement. Fig. 4 infl uence of body refl ection -6 -4 -2 0 2 4 6 100 1000 10000 100000 frequency (hz) resp...

  • Page 37

    31 description for iec 61672-1 acoustical infl uence of operator fig. 5 acoustical infl uence of operator (the distance from the top of the microphone to the operator is approx. 40 cm) fig. 6 acoustical infl uence of operator (the distance from the top of the microphone to the operator is approx. 70...

  • Page 38

    32 description for iec 61672-1 reduction of wind noise by windscreen during outdoor measurements or measurement of ventilation devices, wind noise can falsify measurement results. To counter such problems, the supplied windscreen ws-10 should be mounted on the microphone. The characteristics of the ...

  • Page 39

    33 description for iec 61672-1 fig. 10 infl uence of windscreen ws-10 on acoustical properties of microphone (referred to microphone response without windscreen) fig. 11 frequency response with windscreen correction (ws-10) response (db) frequency (hz) 1.0 0.0 -1.0 10 50 100 500 1 k 5 k 10 k 50 k fr...

  • Page 40

    34 description for iec 61672-1 effect of all-weather windscreen ws-15 the windscreen ws-15 not only reduces measurement errors due to wind noise, it also protects the microphone from rain. The ws-15 characteristics are shown below. Fig. 12-1 frequency weighting a fig. 12-2 frequency weighting c 30 4...

  • Page 41

    35 description for iec 61672-1 effect of rain-protection windscreen ws-16 the windscreen ws-16 not only reduces measurement errors due to wind noise, it also protects the microphone from rain. The ws-16 characteristics are shown below. Fig. 14-1 frequency weighting a fig. 14-2 frequency weighting c ...

  • Page 42: Frequency Fi Elds

    36 description for iec 61672-1 the greatest susceptibility configuration for radio frequency fi elds fig. 16 the greatest susceptibility confi guration for radio frequency fi elds statement of conforming to the basic statement tab. 2 statement of conforming to the basic statement nl-52 nl-42 immunit...

  • Page 43

    37 description for iec 61672-1 adjustment data for sound calibrator tab. 3 adjustment data for sound calibrator frequency (hz) nl-52 correction (db) nl-42 correction (db) 31.5 0.0 0.0 63 0.0 0.0 125 0.0 0.0 250 0.0 0.0 500 0.0 0.0 1000 0.0 0.1 2000 0.2 0.3 4000 0.9 1.3 8000 3.0 3.2 12500 5.9 6.5 160...

  • Page 44: Range

    38 description for iec 61672-1 the lower and upper limits of the linear operating range tab. 4 the lower and upper limits of the linear operating range a weighting 31.5 hz 1 khz 4 khz 8 khz 12.5 khz upper 98.0 138.0 138.0 136.0 133.0 94.0 94.0 94.0 94.0 94.0 lower 25.0 25.0 25.0 25.0 25.0 c weightin...

  • Page 45: Directional Characteristics

    39 description for iec 61672-1 directional characteristics the directional characteristics of a microphone is a measure of its differing sensitivity for sound waves arriving from various angles. Since the prepolar- ized condenser microphone used in the nl-52/nl-42 is a pressure-sensitive type, it sh...

  • Page 46

    40 description for iec 61672-1 tab. 5 directional characteristics of nl-52/nl-42 (rotated horizontal) 1k 2k 4k 8k 12.5k 0 ° 0.00 0.00 0.00 0.00 0.00 10 ° 0.12 -0.02 0.05 -0.07 -0.20 20 ° 0.09 -0.09 0.01 -0.67 -0.79 30 ° 0.17 -0.16 -0.13 -0.94 -1.17 40 ° 0.16 -0.28 -0.66 -1.13 -1.59 50 ° 0.25 -0.50 -...

  • Page 47

    41 description for iec 61672-1 fig. 18 directional characteristics of nl-52/nl-42 (rotated vertical) 1 khz 2 khz 4 khz 8 khz 12.5 khz 00° 10° 20° 30° 40° 50° 60° 70° 80° 90° 100° 110° 120° 130° 140° 150° 160° 170° 180° 190° 200° 210° 220° 230° 240° 250° 260° 270° 280° 290° 300° 310° 320° 330° 340° 3...

  • Page 48

    42 description for iec 61672-1 tab. 6 directional characteristics of nl-52/nl-42 (rotated vertical) 1k 2k 4k 8k 12.5k 0 ° 0.00 0.00 0.00 0.00 0.00 10 ° 0.06 0.01 0.06 -0.03 -0.20 20 ° 0.05 -0.04 0.15 -0.46 -0.42 30 ° 0.08 -0.11 0.06 -0.64 -1.06 40 ° 0.13 -0.26 -0.61 -1.03 -1.90 50 ° 0.16 -0.49 -0.43...

  • Page 49: Random Incidence Response

    43 description for iec 61672-1 random incidence response fig. 19 random incidence response -10 -8 -6 -4 -2 0 2 4 6 1 10 100 1000 10000 100000 (db) frequency (hz) response (db).

  • Page 50

    No. 55753 13-06.