USES:

r Measurement of Sound Pressure Level (SPL)

r Determination of L"o for assessment of hearingloss risk or noise annoyance

r Measurement of cyclical machine noise

r Determination of Sound Exposure Level (L.o,t)

r Measurement of Max. and Min. noise levels

r Spatial averaging of machine noise

r Sound power level measurements according tosurvey method

r Octave or t/s octave frequency analysis with filtersTypes 1624 and 1625

Precision Integrating Sound Level Meters

FEATURES:

r RMS and Peak detector modes

r lmpulse, Fast and Slow time weightings

r In accordance with IEC 804 and 651 Type 1, andANSI S1.4.1983 Type 1, except when measuring SPLwith 2234 which follows a proposed Japanese re-quirement for showing the instantaneous SPL value

r Digital and quasi-analogue liquid crystal display

r 73 dB Pulse range; 70 dB Linearity range

t 24lo 130 dB measuring range (30 to 150 dB withattenuator) in 6 overlapping sub-ranges

r A, C, Lin. and All-pass weightings

The Frecision Integrating Sound Lev-el Meters Types 2230 and 2234 are Type1 precision instruments. Tbeir compre-hensivei ioristruction rand versatilitymake them ideal for all kinds of soundlevel measurements including octaveand 1A gctave frequency analysis using asnap-on filter set.

They carry out five measurements inparallel: SPL, Max., Min., L* and Ls,1,all of which can be obtained for thesame signal. A choice between 2 detec-tor modes (RMS and Peak); 3 timeweightings (Slow, Fast, Impulse), 4 fre-quency weightings (A, C, Lin and AIlpass) is availabie for the measurements.

A partial (Max.1[4in.) reset, a tqtalreset and a pause function increase theusefulness of the insfrument. A linearfree or a linear diffuse field frequencyresponse is obtained by electronic fre-quency weighting for measurements inaccordance with IEC or ANSI stan-qarqs,

. The measurements are displayed with0,1 dB resolution on a large 4 digit liq-uid crystal display. The SPL is continu-ou$ly monitored on a quasi'analogue 60dB scale, Indications of overload, de-pleted batteries and illegal settingS arealso displayed.

AC and DC outputs allow chart ortape recordings and audio rnorritoring of!h: $lL with the selected frgqqenel,werghtrng.

Dqqpiie theis Type 1 performance 'dnd thetnrimerous functions includdd,they are 3?'cm long and weigh leqq lhan1 lig. iThey are easily held,in one,hand,even wheR a Filter.Set is ioiinactei{r.i :.

Both instruments, Type 2230 and2234, arc Precision Integrating SoundLevel Meters which are identical ex-cept for measuring Sound PressureLevel. Type 2230 displays every sec-ond the maximum SPL during theprevious second (IEC, ANSI), whileType 2234 displays the instantaneousSPL value once a second (Japanesestandard). There is no differencewhen measuring L"o or LB,1, as thedata used are obtained by sampling ofthe detector output.

The principle of measurement, sam-pling of the detector output followedby analogue to digital conversion andprocessing by microprocessor, enablesthem to carry out five measurements:SPL, Min., Max., L"o and Ls,1. As allfive measurements are made in paral-lel, the five values can be read succes-sively for the same signal. Min. andMax. can be reset without resettingthe other measurement values. L"oand LB.1 measurements must be car-ried out in "RMS" mode with a Fasttime weighting. AII other measure-ments can be carried out in either"RMS" mode with "Slow", "Fast" or"Impulse" time weightings, or "Peak"mode. AII these measurements, withthe various time weightings and detec-tor modes, can be made with either alinear free field or a linear diffuse fieldfrequency response for the micro-phone. The change in frequency re-sponse is obtained electronically.

BP 01 02-1 6

A, C, Lin (20 Hz to 20 kHz) or AIIPass (10 Hz to 50 kHz) frequencyweightings can be used for all mea-surements. For increased versatilityeach SLM directly accepts the plug-inFilter Sets Type 1624 or 1625 for octa-ve/third octave frequency analysis.Semi- or fully automatic recording ofthe analysis is possible using portableLevel Recorders Types 2317 or 2309.

DC and AC outputs permit chart ortape recording as well as audio moni-toring. A test mode allows a check ofthe complete display. A referencemode allows a quick electrical calibra-tion of each SLM (excluding micro-phone and input stage) and connectedrecording equipment.

SPL measurementsTypes 2230 and2234 carry out mea-

surements of SPL over the rcnge 24 to130 dB (30 to 150 dB with suppliedAttenuator ZF 0020). The measuredSPL values are displayed on the digi-tal display with a resolution of 0,1 dBand on the quasi-analogue displaywith a resolution of 2 dB. The digitaldisplay is updated once a second whilethe quasi-analogue display is updated64 times per second allowing continu-ous monitoring of the measured SPL.

Max./Min.The maximum or minimum SPL

since the last time the instrument wasreset is currently displayed. Max/Mindetectors may be reset without reset-ting the other measurement functions.

Leq

L"o is the sound pressure level aver-aged over the measurement period. Itcan be considered as the continuoussteady sound pressure level whichwould have the same total acoustic en-ergy as the real fluctuating noise overthe same time period. The measure-ment of L".o is based on the equal ener-gy prrnclple:

L"n=rol,os,o+ I,tlr *

where ps is the reference sound pres-sure (20 pPa), p(t) is the time varyingsound pressure and T is the time in-terval over which it is measured.

Types 2230 and,2234 allow L"o mea-surements over periods of any lengthup to approximately 8 hours (limitedonly by battery life).

The digital display gives the currentL"o value which is updated every sec-

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Fig.1. Front panel of Type 2230

ond while the quasi-analogue displayindicates the current SPL. Warningsof "Overload occuring, t" and "Over-load has occured, ^" are also dis-played. The measurement time is ob-tained using the L"o and LB,1 valuesand the conversion table on the backof the instrument. Indication (i) isalso given in cases of incorrect settingsi.e. other than "RMS" "Fast". A pausefunction permits exclusion of unwant-ed noise events from the measure-ment.

LEA,.I (SEL)A-weighted Sound Exposure Level

(LBa,1) is the constant level which ifmaintained for a period of 1 second

would have the same acoustic energy asthe A-weighted measured noise event:

Lee r = 1orogls *IJ(#)',.,T r e f = 1 S

L6,1 m€dsurements can be carried outwith any frequency weighting, and overa period limited only by battery life.The current L6,1 value is digitally dis-played while the current SPL is givenby the quasi-analogue indicator.

MicrophoneTypes 2230 and 2234 are equipped

with a 7/2" prepolarized condenser mi-crophone Type 4155. It has a linear 0oincidence free field frequency re-sponse which is well suited for mea-surements in free field conditions e.g.for outdoor measurements. The mi-crophone frequency response can beelectronically weighted to be linear indiffuse field which is well suited formeasurements in diffuse field condi-tions. When measuring in accordancewith IEC or ANSI standards with a2230, simply select the appropriatemicrophone frequency response, i.e."Frontal" or "Random".

The removable preamplifier, withvery high input impedance and verylow output impedance, allows use ofextension cables between the micro-phone and the Sound Level Meterbody. A Dehumidifier UA 0308 isavailable for use in humid environ-ments.

An Input Adaptor JJ 2614 acceptingdifferent types of plugs may be fittedinstead of the microphone to connectother signal sources,

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in dB referred to continuous signal l€vel

Fig.2. Response of rectifier to tone burst of uarying duration

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Frequency (Hz) Bso32sFig.3. Typical 0" free field frequency response of the complete instrument

l u z u t u u z u u t k 2 k 1 0 k 2 0 k

Frequency lHzl ensao

Fig.4. Typical diffuse field frequency response of the complete instrument

Frequency weightingFour built-in frequency filters give

"A" and "C" weightings in accordancewith IEC 651, and "Lin" (20 Hz to 20kHz) and "All-pass" (10 Hz to 50kHz). The AC and DC output signaland the signal sent to the external fil-ter set are also frequency weighted.

Measuring rangeSix attenuator settings give 6 over-

Iapping 70 dB measuring ranges from24 dB to 130 dB. Use of the supplied20 dB Attenuator ZF 0020 gives ameasuring range from 30 to 150 dB.The displayed value is automaticallycorrected to take account for the pres-ence of this attenuator.

DisplayThe comprehensive liquid crystal

display comprises four digits giving a0,1 dB resolution for display of theselected measured value and a 60 dBquasi-analogue display with 2 dB reso-Iution for continuous visual monitor-ing. The digital and quasi-analog dis-plays are respectively updated onceand 64 times per second.

The following warnings are also dis-played:f: overload is occuring^: overload has occuredBAT (flashing): battery near low levelBAT (flashinC) & t (non-resettable):battery depletedf (non-resettable): illegal setting

Fig.5. Display of Type 2230 and 2234

External FiltersTwo Filters sets are specially de-

signed for use with Types 2230 and2234t the Octave Filter Set Type L624and the rft and l/s Octave Filter SetType 1625. These Filters connect di-rectly to the bottom ofthe Sound Lev,el Meter (Fig.6). In situ frequencyanalysis can then be obtained, and re-corded using Level Recorders Types23L7 or 2309. The Type L624 enablesoctave band analysis, which can be re-corded semi-automatically, and theType 1625 enables \/s octave or octave(with octave or 7h oetave stepping)band analysis which can be recordedfully automatically.

The Filter Set Type 1624 includes10 octave filters with centre frequen-cies from 3t,5 Hz to 16 kHz. The Fil-ter Set Type 1625 includes 31 third-octave filters and 31 overlapping oc-tave filters from 20 Hz to 20 kHz.

Operating modeThe Sound Level Meters can be set

to "Operate" (normal mode), to "Test"and "Ref." modes, The test mode al-

Fig.6. Sound Leuel Meter Type 2230 with1/r - I/e Octaue Filter Set Type 1625

Iows a complete check of the displayby turning on all the segments. In"Ref." mode a reference signal is ap-plied to the input amplifier for electri-cal calibration of the SLM (excludingmicrophone and input stage), and forcalibration of chart or tape recorders.

AC and DC outputsAC and DC outputs allow precise

chart and level recording of the mea-sured SPL. The AC output also allowsaudio monitoring of the input signal.

Use with other instrumentsLevel recordings of noise events or

frequency analysis can easily be car-ried out in situ with the portable Lev-el Recorders Types 2317 or 230g. ForIaboratory analysis the signal can berecorded with the portable Tape Re-corders Type 7005, 7006 or 7007.

CalibrationAcoustical calibration of the com-

plete instrument is carried out usingthe Sound Level Calibrator Type 4280or the Pistonphone Type 4220. Type4220 gives a reference level of L24 dBrc. 20 1rPa, while Type 4230 gives areference level of g4 dB re. 20 uPa.

Fig.7. Sound Leuel Calibrator Type 4250and Pistonphone Type 4220

For electrical calibration of eachSLM and connected instruments suchas chart or tape recorders, a referenceoscillator is built-in. The sensitivityadjustment of each SLM is made us-ing the potentiometer located on theside panel of each instrument.

ResetThe instruments are reset complete-

ly either by pressing RESET "All" orwhen changing the measurementrange. When the instruments are resetmanually, two types of resetting arepossible: a reset of the complete in-strument, or a reset of the max. andmin. detectors, i.e. without interrup-tion of Lu, and LB,1 m€osurements.

PauseA pause function allows exclusion of

unwanted noise events from L"o, Ls,1or Max./Min. measurements. ThePause function also permits spatialaveraging of the SPL.

Power supplyThe power is supplied from 4 alka-

line cells (IEC LR 6) which will pro-vide approximately 8 hours of contin-uous operation. A warning is displayedwhen the batteries are low. The MainsPower Supply and Charger ZG 0254(option), including a drawer with re-chargeable cells can be used to powerthe Sound Level Meter.

Fig. 8. Field Measuring Set

Specifications 2230 and 2234

Lower l imit I Max. I UPPer l imittor S/N I peaK I for s ignals ol

rat io -5dB I levelr I crest tactoL( A - w e i s h t i n s ) | | = 1 0 ( 2 0 d 8 ) "

8393

t031 1 31231 3 3143153

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133

708090

1001 1 012O ^

140.

2424304050607080

. f00958GEi0' F S D o n q u a s i a n a l o g u e d i s p l a y

2 Only with attenuator ZF 0O2O employed3 Vulues ."y diverge sl ight ly from nominal value de-

pendlng on microphone K0 factor

FREOUENCY RESPONSE:See Figs.3 and 4

FREOUENCY WEIGHT]NG:A, C weight ing to IEC 651 Type 1Linear (20 Hz -2o kHzlAl l -pass (10 Hz -50 kHz)

DETECTOR:Character is t ics: RMS, peakLineafity range: 70 dBPulse range: ?3 dBCrest factor capabi l i ty : 13 dB at FSD

Ily: Y_lqlTrIG c HARActERrsfl c s :"1"' to IEC 651 Type 1"F"' to IEC 651 Type l"S"' to IEC 651 Type 1"Peak" ' r ise t ime <50 psMax. Hold decay rale: 0 dB/s (digital)

Leq RESPONSE TtME FOR CONSTANTINPUT SIGNAL:1 s alter reset

MAXI ' I IUM MEASUREMENT PERIOD:Limited only by bat tery l i te

DISPLAY:Digi ta l : 4 d ig i ts 7 segments, l iquid crystal ,8 mm high, resolut ion 0,1 dBOuasi-analogue:60 dB scale wi th 2 dB reso-

Addi t ional lunct ions:Over load occurr ing: Iover load has occurred: ̂Bat tery near low level : BAT f lashingBattery low level : BAT ( f lash.) i (non-reset . )l l legal set t ing: t

AC OUTPUT:1 V RMS for fu l l scale. output impedance<120 Q, short c i rcui t protected, mini - jacksocket

DC OUTPUT:3 V for fu l l scale, O V bot tom scale, 50 mV/dB,output impedance <500 Q, short c i rcui t pro-tected, mini - jack socket

RESET FUNCTION:Automat ic reset a l l occurs when changingFSD set t ing.Reset a l l : Max. /min. detectors, Leq. LE.T andoverload detector are resetReset max. /min. : Only max./min detectorsare reset

MICROPHONE:Typer 1/2 inch B & K Prepolar ized condenserMicrophone Type 4155Sensi i iv i ty : 50 mV/PaCapaci lance: 15 pFWindscreen el fect : <0,9 dB up to 10 kHz

CALIBRATION:Acoust ical : With Sound Level Cal ibratorType 4230 or Pistonphone fype 4220 by po-tent iometer adjustmentElectr ical : With internal reference source bypotent iometer adjustment

REFERENCE CONDITIONS FORACOUSTICAL CALIBRATION WITHTYPE 4230:Type ol Sound Fie ld: FreeRef e lence Incidence Di leci ion: Perpendicu-lar to microphone diaphragmBeference SPL: 94 dB (re 20 iiPa)Belerence Flequency: 1 kHzRef elence Temperature: 20' CRelerence Measur ing Range: 110dBFSD

WARM.UP TIME:< 5 s l o r 0 , 5 d B : < 1 0 s f o r 0 , 1 d B

ffirttil,,oF HUMIDITY (Ar 4o'c AND

<0 ,5 dB f o r 30%<RH<90%

EFFECT OF TEMPERATURE:Miclophone: -0.006 dB/"C typical lyComplete instrument:<0 ,5 dB -10 t o +50 "C

?Nr""r;; '"n ranse: -10 to +50'c (+14 to

Storage_without bat ter ies: -20 to +70"C (-4to 158 "F )

EFFECT OF MAGNETIC FIELD:80 A/m (1 Orsted) at 50 Hz gives:<25 dB (A) or <44 dB (Lin)

VIBRATION SENSITIVITY: 72 dB max. at40 Hz and 1 ms- ' .

BATTERIES:Typer Fou| I ,5 V Alkal ine cel ls IEC type LR 6(B&K order No. QB 0013)Li fe: approx. 8 hours

3)" : tL " ?Y,f }l',"ri" i{r" X'', f l,''

860 g (1,9 lb) wi th bat ter ies

ACCESSORIES INCLUDED:Hal f - inch Prepolar ized CondenserMicrophone.. . . . . . . . . . . Type 41552,5 mm mini- jack plug (x2) . . . . . . . . . . . . . . . . . .JP 0213Windscreen . . . . . . . . . . . . . . . . UA 0237Input Adaptor . . . . . . . . . . . . . JJ 2614Screwdr iver. . . . . . . . . . . . . . . .QA 0001Cel ls (x4). . . . . . . . . . . . . . . . . . . .QB 001320 dB Al tenuator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2F OO2O

ACCESSOBIES AVAILABLE:Carry ing case. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . KE 0226Tr ipod. . . . . . . . . . . . . . . . . . . . . . . . . .U4 0801Sound Level Ca| ibrator . . . . . . . . . . . . . . . . . . . . Type 4230Level Recorder Cable. . . . . . . . . . . . . . . . . . . . . . . . . . .AO 01733 m Microphone Extension cable . . . . .AO 0027Mains Power Supply and Charger. . . . .ZG 0254

lut ion for current sPL

Brtiel &Kjer,@.P r i n t e d i n D e n m a r k b y N e r u m O f f s e l

DK-2650 Naerurn Denmark Te lephone: +452800500 Te |ex :37316 bruka dk ' Fax . :02801405