Related Manuals for BRUEL & KJAER 4204
Summary of Contents for BRUEL & KJAER 4204
- Page 1 Technical Documentation Reference Sound Source Type 4204 User Manual English BE 0105 – 15...
- Page 3 Reference Sound Source Type 4204 User Manual April 2013 BE 0105−15...
- Page 4 Safety Considerations This apparatus has been designed and tested in accordance with IEC/EN 61010 – 1 and ANSI/UL 61010 – 1 Safety Requirements for Electrical Equipment for Measurement, Control and Laboratory Use. This manual contains information and warnings which must be followed to ensure safe operation and to retain the apparatus in safe condition.
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Page 5: Table Of Contents
Contents CHAPTER 1 Introduction......................1 About This Manual ....................1 Reference Sound Source Type 4204..............1 CHAPTER 2 Operation......................5 Connection of Mains Supply ................5 Sound Power Measurements................6 Sound Absorption Measurements..............12 Sound Insulation Measurements ............... 13 CHAPTER 3 Characteristics.................... -
Page 7: Chapter 1 Introduction
Type 4204 is intended for use as a reference sound source for determination of the sound power output of equipment by the various comparison methods, including the method described in... - Page 8 Reference Sound Source Type 4204 — User Manual Type 4204 is also used for measuring environmental correction K when determining sound power according to ISO 3744. It is also useful in the field of building acoustics to determine the sound absorption and sound insulation of a room.
- Page 9 115 V/60 Hz operating voltages. Temperature, barometric pressure, humidity and rotational speed are all given on the calibration certificate. The maximum interval between successive calibration is 24 months. If there are signs of physical damage to Type 4204, then a recalibration is recommended.
- Page 10 Reference Sound Source Type 4204 — User Manual...
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Page 11: Chapter 2 Operation
Main Voltage Settings Type 4204 operates from either a 50 Hz or a 60 Hz mains supply of 100, 115, 127, 220 or 240 V AC. The influence of mains voltage variations is discussed in section 3.4. The fuse and voltage selector are located on the bottom panel of the instrument. -
Page 12: Sound Power Measurements
= sound power level of the device under test (dB re 1 pW) = sound power level of Type 4204 (dB re 1 pW) = sound pressure level of the device under test (dB re 20 µPa) = sound pressure level of Type 4204 (dB re 20 µPa) Measurements are normally carried out in 1/3-octave or octave bands. - Page 13 CHAPTER 2 Operation Fig.2.1 Typical Calibration Certificate for Reference Sound Source Type 4204 (three pages) 120562...
- Page 14 Reference Sound Source Type 4204 – User Manual 120563...
- Page 15 CHAPTER 2 Operation 120564...
- Page 16 Reference Sound Source Type 4204 – User Manual A measuring system for automatic sound power determination is shown in Fig.2.2. This is a recommended system for measurements to the following standards: ISO 3741: Determination of sound power levels of noise sources Precision methods for broad- band sources in a reverberation room.
- Page 17 This method applies when it is not possible to move the machine, but when a similar location may be found for Type 4204. This requires a diffuse sound field in the part of the room where the sound pressure measurement is to be performed. A method for checking whether the sound field is diffuse is normally given in the standards.
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Page 18: Sound Absorption Measurements
Type 4204. For each frequency band, the background noise level should be measured with neither the machine nor Type 4204 operating. Measurements should then be carried out with the machine in operation, and finally with Type 4204 in operation. -
Page 19: Sound Insulation Measurements
CHAPTER 2 Operation To obtain a logarithmic scale, the following reference values are introduced: p = 20 µPa, –12 = 10 W and A = 1 m and eq. (2.3) becomes: 4ρcW ----- - ------- - 10log ---------------- - ------- - 10log 10log 10log... - Page 20 120556 3160-A PULSE LAN-XI In some cases, i.e., when a high sound insulation is present, the power output of Type 4204 might be too low for use as a sound source in the transmitting room. In such circumstances another source could be used in the transmitting room and Type 4204 used as reference in the receiving room.
- Page 21 CHAPTER 2 Operation where: R = the transmission loss λ = the wavelength at the centre frequency of the band = the surface area of the transmitting room = the volume of the transmitting room S = the area of the test specimen = the reference area of 1 m = the sound power level of the reference source This formula is derived in Technical Review No.3, 1980.
- Page 22 Reference Sound Source Type 4204 – User Manual...
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Page 23: Chapter 3 Characteristics
Over the frequency range 100 Hz to 10 kHz the sound power level of the Type 4204 is above 70 dB re 1 pW in each 1/3-octave band (see Fig. 3.1). The Type 4204 can operate either from a 50 Hz or 60 Hz mains supply. The instrument is very stable, the output power varying less than ±... -
Page 24: Factory Calibration
Type 4204 placed on a reflecting plane and in free-field conditions, respectively. The curves were drawn for a 50 Hz mains supply to Type 4204, but use of a 60 Hz supply does not noticeably modify the directional characteristics. It can be seen from the curves that the... - Page 25 The Directivity Index, DI, in dB measured vertically above Type 4204 in 1/3-octave bands is shown in Fig.3.4. These values were calculated from the directional characteristics given in Fig.3.2 (i.e., Type 4204 radiating in a free field above a reflecting plane) according to the equation given in ISO/DIS 6926 for reference sound sources, i.e., DI = L –...
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Page 26: Influence Of Rotational Speed
Frequency (Hz) Influence of Rotational Speed The rotational speed of Type 4204 affects its sound power output. The calibration certificate shown in Fig.2.1 indicates the rotational speed during calibration for mains voltage line frequencies of both 50 Hz and 60 Hz. Deviations from this speed will lead to changes in the sound power output as shown in Fig.3.5. - Page 27 Variations in the sound power emitted by Type 4204 due to ±10% (50 Hz line frequency) and ±5% (60 Hz line frequency) variation of the supply voltage are less than ± 0.3 dB.
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Page 28: Acoustical Effect Of Barometric Pressure
Acoustical Effect of Barometric Pressure The sound power output of Type 4204 depends upon the barometric pressure at the location of operation. The barometric pressure influences the specific acoustic impedance of the medium into which the source radiates. -
Page 29: Acoustical Effect Of Ambient Temperature
± 0.2 dB. Field Calibration Field calibration of Type 4204 is carried out by determining the rotational speed f of the sound source, and the ambient pressure B and ambient temperature T at the operating location, and applying the corrections given in Fig. - Page 30 Reference Sound Source Type 4204 – User Manual where B is the barometric pressure given on the calibration certificate. 3) Measure the ambient temperature T (in Kelvin) and add a correction factor ∆L to the sound power levels given on the calibration certificate. ∆L is given by: ...
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Page 31: Influence Of Reflecting Plane
1.5 m away from other large objects. Fig.3.8 shows the sound power output from a Type 4204 placed on the floor in a corner 0.35 m and 1 m from the walls, relative to the sound power output when placed 1.5 m from the walls. From the figure, the increase in the sound... - Page 32 Reference Sound Source Type 4204 – User Manual Fig.3.8 Sound power level emitted by the Type 4204 when placed on the floor in a corner 1 m and 0.35 m from the two walls, relative to the power emitted when placed 1.5 m from the walls...
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Page 33: Carrying Case We-0268
Type 4204. If there are signs of physical damage to Type 4204 then a recalibration is recommended. We recommend that your Type 4204 is calibrated at a Brüel & Kjær ISO 17025 certified laboratory bi-annually or annually. - Page 34 Reference Sound Source Type 4204 – User Manual...
- Page 35 Chapter 4 Specifications POWER SUPPLY VARIATION OF SOUND POWER OUTPUT Supply Voltage: 110, 115, 127, 230 or 240 V AC, 50 With Supply Voltage: (± 10% (50 Hz) and ± 5% or 60 Hz (60 Hz) of nominal voltage): < ± 0.2 dB @ 50 Hz line Power Consumption: 50 Hz: 500 VA;...
- Page 36 Reference Sound Source Type 4204 – User Manual Compliance with Standards CE-mark indicates compliance with: EMC Directive and Low Voltage Directive. C-Tick mark indicates compliance with the EMC requirements of Australia and New Zealand. Safety EN/IEC 61010–1: Safety requirements for electrical equipment for measurement, control and laboratory use.
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Page 37: Chapter 4 Specifications
CHAPTER 4 Specifications Any adjustment, maintenance or repair of the sound source under voltage must be avoided as far as possible and, if unavoidable, must be carried out only by trained service personnel. Mechanical Note that there is increased risk of injury if the sound source is operated without its protective casing. - Page 38 Reference Sound Source Type 4204 – User Manual...
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Page 39: Index
Barometric pressure ..........29 Mains fuse rating ............5 Measurement methods..........10 Mechanical ............... 30 Calibration..............29 Calibration Certificate for Type 4204 ......7 Carrying case WE-0268..........27 Power consumption..........29 Comparison method ..........11 Power measurement arrangement......10 Compliance with Standards ........30 Power supply............ - Page 40 Reference Sound Source Type 4204 – User Manual...
- Page 42 HEADQUARTERS: Brüel & Kjær Sound & Vibration Measurement A/S · DK-2850 Nærum · Denmark Telephone: +45 7741 2000 · Fax: +45 4580 1405 · www.bksv.com · info@bksv.com Local representatives and service organisations worldwide...