Product Data Sheet: Multifunction Acoustic Calibrator — Type 4226
Contents
1. The calibrator is easy to turn controls the variable gain am plifier of the calibrator This method of signal generation tained depends essentially on the reference microphone which is itself very stable with respect to time and temperature variation The SPL pro duced is practically independent of atmospheric pressure changes The calibrator gives you a signal when the constant SPL in the coupler is correct The response obtained from a mi crophone of any type freefield or pressure will always be its pressure response However the main interest Microphone Timea Weighing F Time Sound field Creel Fachor Woighting 5 S Sound Level dA a Prese a Fir fede for sound level meters is the free field response Because the difference be tween the pressure response and the free field response is known for Bruel amp Kj r microphones you can correct the SPL in the coupler as a function of frequency to obtain a flat response from an ideal free field mi crophone This SPL correction is au tomatically applied by the calibrator when you specify which Bruel amp Kj r microphone is to be calibrated The construction of the calibrator also enables you to connect an exter nal generator for example for fre quency sweeps or to pick up an electrical calibration signal for ex ample for filter checks L F Transducer H F Transducer Reo nda Y y E dees to calibrate Electronic Refere2. the inverse A weighting and the cor Ambient Pressure 0 00055dB hPa in the range 650hPa to 1080hPa max press uncer tainty 30 hPa To satisfy IEC 942 Class 1 requirements Magnetic Field Sensitivity No observable ef fect lt 0 01 dB at 100 A m FREQUENCY RESPONSE Pressure Field Linear 94dB 104dB and 114dB SPL and inverse A weighting 94dB SPL at 1 kHz Equivalent 0 Free field Linear 94dB 104dB and 114dB SPL and In verse A weighting 94dB SPL at 1 kHz LEVEL ACCURACY AT FIXED FREQUENCIES Lin and inv A weighting Pressure Field re 1 kHz 31 5Hz to 125Hz 0 15dB 250 Hz to 500 Hz 0 10 dB 2kHz to 4kHz 0 15 qB 8 kHz 0 25dB 12 5kHz to 16kHz 0 5dB Equivalent 0 Free field re 1 kHz 31 5Hz to 125Hz 250 Hz to 500 Hz 0 2dB 0 10dB rections for freefield and reference microphone response cannot be ap plied since they only refer to the fre quencies delivered by the 4226 s gener ator General Type 4226 is a laboratory precision Instrument Its size and the included power supply of 4 alkaline cells make the instrument easy to use in situ for example with a sound level me ter or a large measurement set up in an anechoic chamber The simplicity of use also makes it highly portable no specific documentation or correc tion tables are required for checks on standard Bruel amp Kjexr sound level meters noise dose meters micro phones etc 2 kHz 4 kHz 0
3. 2 dB 0 3 dB 8 kHz 0 5dB 12 5k 1 0 dB 16 kHz 1 5dB TOTAL HARMONIC DISTORTION lt 2 Additional Functions TIME WEIGHTING TESTS Frequency 2 kHz preselected Test Level Typically 94dB Adjustable approx 12dB Signal Continuous reference and tone burst Level Between Bursts Ref level 20dB Burst Duration 500 ms S and 200 ms F CREST FACTOR TEST Frequency 2kHz preselected Test Level Typically 94 qB Adjustable approx 12dB Signal Continuous reference and tone burst of 40Hz repetition frequency Crest factor 3 at preselected and higher frequencies Note All burst signals consist of an integral number of sine waves with amplitude shifting at zero crossing Specifications 4226 continued DOSE METER CALIBRATION EFFECTIVE COUPLER VOLUME Environmental Calibration Period 30s Approximately 400 cm at 31 5Hz decreasing to Ambient Pressure 650 hPa to 1080 hPa Obtained Doses at 1 kHz approximately 30cm at 1kHz Obtained by feedback SPECIFICATIONS VALID FOR Dimensions and Weight BRUEL amp KJ R MICROPHONE TYPES including mahogany case A R P R Pressure Field Type 4180 Length 265mm 10 4in 0 26 EOUN 0 18 0 01 Equivalent 0 Free Field Width 125mm 4 9in Height 62mm 2 4 in Micro Po Falcon Weight 1 5kg 3 3 Ib phone setting 2 62 0 20 0 73 0 03 Traditional Types Range Types 26 20 1 90 2 90 0 12 AC OUTPUT 4129 4130 4176 4187
4. 4188 Output Voltage 12 5mV 0 5mV at settings 94 dB 1 kHz and pressure mode Voltage chang i 4155 4165 4189 4190 es according to the selected level type of mi Note All values are typical at 25 C 77 F un crophone sound field and function Signal for 4133 4134 4147 4191 4192 less measurement I E is ies All testing time weighting and crest factor capabili 4149 4193 uncertainty values are specified at 20 i e ex ties as above except that the crest factor is 10 panded uncertainty using a coverage factor of 2 Note The acoustic output is switched off when a plug is inserted in the AC OUT socket Output Impedance 6009 short circuit proof COMPLIANCE WITH STANDARDS Frequency Response 0 2dB from 31 5Hz to 16 kHz in pressure mode EXTERNAL GENERATOR INPUT CE mark indicates compliance with EMC Directive Input Voltage 0 5V 1 5V Input Impedance 47 KQ Safety EN 61010 1 and IEC 1010 1 Safety requirements for electrical equipment for Frequency Response in the Coupler i nol and abor 31 5Hz to lt 8kHz 0 15dB measurement control and laboratory use 8kHz to lt 12 5kHz 0 25 qB 12 5kHz to 16kHz 0 50dB EMC Emission EN 50081 1 Generic emission standard Part 1 Residential commercial and Note These tolerances are relative to the in light industry E verse pressure response of the reference micro EN 50081 2 Generic emission standard Part 2 Industrial environment phone see User Manual Only Press
5. Function NOMINAL SOUND PRESSURE LEVELS 94dB 104dB and 114dB REFERENCE SOUND PRESSURE LEVEL at Reference Ambient Conditions 94dB 0 2dB re 20uPa at 1 kHz 10dB AND 20dB LEVEL STEP ACCURACY 0 1 dB for f lt 8kHz 0 2dB for f gt 8kHz NOMINAL FREQUENCIES From 31 5Hz to 16kHz in octave steps plus 12 5 kHz FREQUENCY ACCURACY 1 re the ISO 266 stated exact frequencies FREQUENCY STABILITY Better than 30 ppm REFERENCE AMBIENT CONDITIONS Ambient Temperature 20 C 68 F Ambient Pressure 1013hPa INFLUENCE OF AMBIENT CONDITIONS at Reference Sound Pressure Level Ambient Temperature 0 002 dB C in the range 10 C to 50 C max temp uncertainty 5 C Lat oi gil 3 si A state z E E fl l ii ija 7 7 t ie iat Fig 4 Type 4226 as ddivered in its case ried out with this signal are similar to the acoustic tests described above The only difference is the signal for crest factor capability checks which has a crest factor of 10 The electrical test signals are for example conven ient for calibrating or checking re corders filters and other instruments related to acoustic work Use with an External Generator A generator with an output voltage between 0 5V and 1 5V can be con nected to this socket see Fig 2 The 4226 regulates the level in the cou pler and ensures a constant SPL rel ative to the inverse reference microphone response When using an external generator
6. Product Data Multifunction Acoustic Calibrator Type 4226 USES O Calibration and comprehensive check of 1 2 and 1 4 microphone set ups and acoustic instruments conforming to IEC 651 and ANSI S 1 4 1983 such FEATURES O Conforms to IEC 942 1988 and ANSIS1 40 1984 O Wide frequency range tones from 31 5 Hz to 16 kHz in octave steps plus tone at 12 5 kHz as sound level meters dose meters etc O Calibration levels of 94dB 104dB and 114dB O Checks of filter sets and other frequency dependent instruments The Multifunction Acoustic Calibra tor Type 4226 enables you to check for use so you can make comprehensive ee eee pyi the proper function of microphones i Timer sound level meters and other related checks whenever extra confidence is a instruments The 4226 generates accu required in a measurement C o E rate and stable signals with a frequen Ball Low cy varying from 31 5Hz to 16kHz in How the Calibrator Works on octave steps plus a signal at 12 5 KHz Fig 2 shows a block diagram of the The test signal can either be applied 4226 A crystal locked sine generator fies omar pate to a 1 2 or 1 4 microphone with the Type 4226 coupler provided or picked up from an produces signals of very stable fre g a electrical output For ease of use the quency These signals pass through a a 4226 can simulate a constant free field variable gain amplifier and are sent n and can apply a very ac
7. aching the last 10 of the battery life Enclosure IEC 529 1989 Protection provided by enclosures IP 20 Ordering Information Type 4226 Multifunction Acoustic Calibrator Optional Accessories Includes the following accessories UA 1231 1 2 Microphone Adaptor DP 0682 Type 4003 4006 Adaptor 16 mm DP 0781 1 4 Microphone Adaptor DP 0750 Type 4004 4007 Adaptor 12 mm 2xJP 0213 2 5mm Mini Jack Plug AO 0481 Mini Jack to BNC cable 1 2m 4xQB 0013 Alkaline Batteries IEC LR6 Br el amp Kj r reserves the right to change specifications and accessories without notice Br el amp Kj r WORLD HEADQUARTERS DK 2850 N rum Denmark Telephone 45 45 80 05 00 Fax 45 45 8014 05 Internet http www bk dk e mail info ok dk Australia 02 9450 2066 Austria 00 43 1 865 7400 Belgium 016 44 92 25 Brazil 011 246 8166 Canada 514 695 8225 China 10 68419 625 10 6843 7426 Czech Republic 02 67021100 Finland 0 9 229 3021 France 01 69906900 Germany 06103 908 5 Hong Kong 2548 7486 Hungary 1 2158305 Italy 02 5760 4141 Japan 03 3779 8671 Republic of Korea 02 3473 0605 Nederland 0 30 6039994 Norway 66 90 4410 Poland 0 22 40 93 92 Portugal 1 4711453 Singapore 65 275 8816 Slovak Republic 073789520 Spain 91 3681000 Sweden 08 71127 30 Switzerland 01 940 09 09 Taiwan 02 713 9303 United Kingdom and Ireland 0181 954 2366 USA 1 800 332 2040 Local representatives and s
8. ctor Capabilities The signal used to check an instru ment s crest factor capability has the same RMS level as the constant test signal set on the calibrator The check IS made by comparing the readings with both signals which should be identical within specified tolerances The signal applied in the acoustic coupler has a crest factor of 3 To check the crest factor capability of sound level meters standards re quire a crest factor capability of 10 for Type O and 1 Instruments the signal from the AC output socket crest factor 10 can be applied di rectly to the sound level meter input stage It is valid to check a sound level meter in this way as the crest factor capability is normally limited by the detector of the sound level me ter and not by the microphone Calibrating a Noise Dose Meter Noise dose meters are calibrated us ing one of the three calibrated levels and the 4226 s built in timer The timer automatically switches off the stabilised SPL after 30s This gives a well defined noise dose to calibrate the meter The frequency response of the noise dose meter is checked by applying the inverse A weighted level and by changing the signal frequency AC Output This socket outputs a signal similar to the signal normally sent to the acoustic transducer Consequently all the electrical tests which can be car Fig 3 Checking and calibrating a sound leva meter with Type 4226 Specifications 4226 Calibration
9. curate inverse to the transducers located in the p reaa np Arwe gnting Correction 4226 s acoustic coupler A reference En F All you have to do is check that the microphone that is symmetrical to bo ni isplayed and nominal values are iden oe so tical within the given tolerances An the microphone to be calibrated is sit external generator can also be connect uated in the coupler both are exposed ix ed to the 4226 if a frequency sweep is to the actual SPL in the coupling vol u al J ume The reference microphone s drives a compression loop which in Eriten ER Tost Level Introduction has many advantages over a wide ainakin frequency range it gives a very accu The high reliability of electronic rate and stable SPL The SPL ob measuring instruments such as sound level meters enables you to make accurate measurements after a simple check with a single tone cali brator In many cases this check is also carried out after each measure ment to validate the results To make sure an instrument is working cor rectly more comprehensive checks are required periodically You can make such a check and calibration with the Multifunction Acoustic Cal ibrator Type 4226 on microphones Bruel amp Kj r O Free field simulation for most 1 2 Br el amp Kj r microphones O Inverse A weighting O Recurrent pulses for time weighting and crest factor checks sound level meters and other acoustic Instruments
10. ervice organisations worldwide BP 0772 16 97 07
11. hted measuring instrument means making sure that it reads 94dB within the tolerances Note at 31 5 Hz the level in the cou pler will reach 134qB Checking Input Attenuators With the 4226 there are three cali brated levels 94 104 and 114dB at all frequencies You can use these three levels for example to check for the proper function of the input at tenuators of an instrument such as the 20dB Input Attenuator ZF 0020 for Bruel amp Kj r sound level meters or for calibration of a level recorder Checking Time Weighting Networks This check is made by comparing the Instrument readings for short pulses with the reading obtained for a con tinuous signal of the same level The difference depends on the time weighting The preset test frequency IS 2kHz in accordance with IEC 651 however whatever the frequency each pulse is an integer number of cycles The pulses are automatically repeated one pulse of approximately 200 ms every 2s for the F Fast time weighting and one pulse of approxi mately 500ms every 8s for the S Slow time weighting The delay be tween pulses ensures that the detec tor of the instrument under test has time to decay before the next pulse To check the time weighting the feedback loop is disconnected since its response time is incompatible with this test The pulses in this case are obtained by an intermittent 20 dB attenuation of the constant level set by a potentiometer Checking Crest Fa
12. nce Microphone Circuitry A f hey 880608e Fig l Simplified cross section of the acoustic coupler Calibrating the Sensitivity An SPL of 94dB 0 2dB re 20uPa at 1 kHz can be used for calibration pur poses You can use other calibration levels and frequencies with slightly reduced accuracy See specifications Checking the Frequency Response Type 4226 delivers a very stable tone with a frequency varying from 31 5Hz to 16kHz in octave steps with an extra tone at 12 5kHz The 12 5kHz tone is used for checking the highest frequency specified for Type 1 sound level meters The actual fre quency of the tone corresponds to those frequencies recommended in ISO 266 Checking A weighting Networks A 94dB inverse A weighted SPL can be applied in the acoustic coupler of the 4226 This means that an SPL of 94dB plus the corrections due to the microphone type and the sound field type plus the inverse A weight Ing correction is produced in the cou pler All the corrections are of course frequency dependent so to check an SPL dB Sound Mic Field 114 Lin a B Press 104 _ 4 E env a 94 Acoustic Coupler Detector Corrector AC Output Falcon c Tradi tional Ext Gen Reference Frequency Display L W Frequency C o n t i o e r Timer 892146 1e Frequency Fig 2 Simplified block diagram of the Multifunction Acoustic Calibrator Type 4226 A weig
13. ure and CISPR 22 Radio disturbance characteristics of information technology Linear response are possible with external gen equipment Class B Limits For other types of microphones see manual erator FCC Rules Part 15 Complies with the limits for a Class B digital device Standards EMC Immunity EN 50082 1 Generic immunity standard Part 1 Residential commercial and The 4226 complies with agi nenely eo IEC942 1988 Sound Calibrators Class 1 at EN 50082 2 Generic immunity standard Part 2 Industrial environment Reference Sound Pressure Level Note 1 The specified calibration levels will not deviate more than 0 5 dB when ANSI S1 40 1984 Specifications for Acoustical exposed to RF specified in EN 50082 2 10 V m field Calibrators Temperature IEC 68 2 1 amp IEC 68 2 2 Environmental Testing Cold and Dry Heat ge Operating Temperature 10 to 55 C 14 to 131 F General Specifications Storage Temperature 25 to 70 C 13 to 158 F STABILISATION TIME The LED corresponding to the selected frequen Humidity IEC 68 2 3 Damp Heat 90 RH non condensing at 30 C 86 F cy lights continuously when the SPL is stabilised i Bas 10s Non operating IEC 682 6 Vibration 0 3 20 m s 10 500 H Type 4x1 5V alkaline cells IECLR6 coe ee Life Time 10 hours approx at 20 C with alka 7 2 ihe batteries IEC 68 2 29 Bump 3000 bumps at 250 m s Battery Check The Batt Low LED is lit when re
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