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Hand-held Analyzer 2250 Light – User Manual184

ep,d,v

: The Daily Noise Exposure Level for a user-defined reference period. L

ep,d,v

is calculated from the measured L

and the settings of Exposure Time and

Reference Time. Used, for example, for calculating a Weekly Noise Exposure

Level, by setting the Reference Time to 40 h.

Loudness, Loudness

Level:

Loudness is the subjective judgement of intensity of a sound by humans.

Loudness depends upon the sound pressure and frequency of the stimulus

and whether the sound field is diffuse- or free-field. The unit is the Sone.

Loudness Level = 10*log2(Loudness) + 40. The unit is the Phone.

The Zwicker method of calculation of stationary loudness based on 1/3-octave

measurements is described in ISO 532 – 1975, Method B.

#CPeaks(>140dB): The number of 1 s peak sound levels over 140 dB. ‘C’ denotes that the

C-frequency weighting is used.

Three peak counters are available – one with a user-definable value (set to

140 dB by default), one with 137 dB and one with 135 dB value. Used for

assessing possible damage to human hearing caused by very high, short-

duration, noise levels.

The European Noise at Work Directive 2003/10/EC defines the following limit

and action values:

Limit Value: 140 dB corresponding to 200 Pa

Upper Action Value: 137 dB corresponding to 140 Pa

Lower Action Value: 135 dB corresponding to 112 Pa

NC, NC Decisive Band: Noise Criteria is used to rate steady-state continuous noise in a room from

all types of equipment, including fans, mixing boxes, diffusers, etc.

The rating is determined from 1/1-octave L

Zeq

spectra compared with NC

curves (based on equal loudness curves). The NC rating is the value of the

rating curve that falls entirely above the measured data. The Decisive Band

is the frequency band ‘touching’ the NC curve.

Defined in ANSI 12.2–2008

NCB, NCB Classification,

Rumble, Hiss, RV:

Balanced Noise Criteria is a refinement of NC.

The rating is determined by the SIL value and gets the Classification (R) for

Rumble, if the spectrum is rich in low frequency sound (16 Hz to 500 Hz),

the Classification (H) for Hiss, if the spectrum is rich in high frequency sound

(1 kHz to 8 kHz), or the Classification (RV) for Vibration and Rattle if the

spectrum at low frequencies (16 Hz to 63 Hz) is likely to produce audible

rattling in lightweight building elements.

The details of the NCB rating are defined in ANSI S12.2-1995

NR, NR Decisive Band: Noise Rating rates noise levels at public or private indoor areas.

The rating is determined from 1/1-octave L

Zeq

spectra compared with NR

curves (based on equal loudness curves). The NR rating is the value of the

highest NR curve ‘touched’ by the measured spectrum. The Decisive Band

is the frequency band ‘touching’ the NR curve.

Defined in ISO R1996(1971)

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