IEC 62585:2012 provides information on the corrections required over a range of frequencies in order for a periodic test of a sound level meter to be performed according to IEC 61672-3. These corrections include; corrections for the typical effects of reflections from the case of the sound level meter and diffraction of sound around the microphone; corrections for the deviation of the typical microphone frequency response from a uniform frequency response, where the actual microphone response cannot be measured; and corrections for the influence on the frequency response of a typical microphone of a specified windscreen and any other accessory that is part of the configuration for normal use of the particular sound level meter submitted for testing. This International Standard includes discussion about uncertainties of measurement of the required corrections. In some instances a maximum permitted expanded uncertainty for the manufacturer or testing laboratory is given. The aim of this International Standard is to ensure that the adjustment value at the calibration check frequency and all corrections are determined using consistent and appropriate methods. It is intended that this International Standard will be used by manufacturers to determine adjustment values and corrections, by laboratories performing pattern evaluation tests according to IEC 61672-2, and by laboratories performing periodic tests according to IEC 61672-3. Laboratories performing periodic tests according to IEC 61672-3 will also need to consult this International Standard to ensure that the expanded uncertainties of measurement for the corrections quoted by the manufacturer do not exceed the maximum permitted values.<\/p>\n
| PDF Pages<\/th>\n | PDF Title<\/th>\n<\/tr>\n | ||||||
|---|---|---|---|---|---|---|---|
| 6<\/td>\n | English CONTENTS <\/td>\n<\/tr>\n | ||||||
| 8<\/td>\n | INTRODUCTION <\/td>\n<\/tr>\n | ||||||
| 9<\/td>\n | 1 Scope <\/td>\n<\/tr>\n | ||||||
| 10<\/td>\n | 2 Normative references 3 Terms and definitions <\/td>\n<\/tr>\n | ||||||
| 11<\/td>\n | 4 Reference environmental conditions 5 Uncertainties of measurement <\/td>\n<\/tr>\n | ||||||
| 12<\/td>\n | 6 General requirements for measurement of adjustment value and corrections <\/td>\n<\/tr>\n | ||||||
| 13<\/td>\n | Figure\u00a01 \u2013 Mounting methods for the sound level meter <\/td>\n<\/tr>\n | ||||||
| 14<\/td>\n | 7 Submission and inspection 8 Determination of the adjustment value at the calibration check frequency <\/td>\n<\/tr>\n | ||||||
| 15<\/td>\n | 9 Determination of corrections for the typical effects of reflections from the case of the sound level meter and diffraction of sound around the microphone 10 Determination of corrections for the deviation of the microphone free-field frequency response from a uniform frequency response <\/td>\n<\/tr>\n | ||||||
| 16<\/td>\n | 11 Determination of corrections for the use of windscreens and similar accessories 12 Determination of corrections over a range of frequencies when a sound calibrator is recommended for use by the sound level meter manufacturer <\/td>\n<\/tr>\n | ||||||
| 17<\/td>\n | 13 Determination of corrections over a range of frequencies when a comparison coupler is recommended for use by the sound level meter manufacturer <\/td>\n<\/tr>\n | ||||||
| 18<\/td>\n | 14 Determination of corrections over a range of frequencies when an electrostatic actuator is recommended for use by the sound level meter manufacturer 15 Documentation <\/td>\n<\/tr>\n | ||||||
| 20<\/td>\n | Annex A (normative) Calibration check frequency \u2013 Determination of the adjustment value <\/td>\n<\/tr>\n | ||||||
| 21<\/td>\n | Figure\u00a0A.1 \u2013 Diagrammatic representation of factors for considerationin optimising adjustment value at the calibration check frequency <\/td>\n<\/tr>\n | ||||||
| 22<\/td>\n | Annex B (normative) Determination of the effects of reflections from the case of the sound level meter and diffraction of sound around the microphone <\/td>\n<\/tr>\n | ||||||
| 23<\/td>\n | Annex C (normative) Determination of the effects of the use of windscreens and similar accessories <\/td>\n<\/tr>\n | ||||||
| 24<\/td>\n | Annex D (informative) Determination of corrections for use with sound calibrators to determine equivalent free-field response at all frequencies of interest Figure\u00a0D.1 \u2013 Measurement steps using a sound calibrator <\/td>\n<\/tr>\n | ||||||
| 27<\/td>\n | Annex E (informative) Determination of corrections for use with comparison couplers to determine equivalent free-field frequency response at all frequencies of interest Figure\u00a0E.1 \u2013 Measurement steps using a comparison coupler <\/td>\n<\/tr>\n | ||||||
| 30<\/td>\n | Annex F (informative) Determination of corrections for use with electrostatic actuators to determine equivalent free-field frequency response at all frequencies of interest Figure\u00a0F.1 \u2013 Measurement steps using an electrostatic actuator <\/td>\n<\/tr>\n | ||||||
| 33<\/td>\n | Annex G (informative) Comparison techniques <\/td>\n<\/tr>\n | ||||||
| 36<\/td>\n | Annex H (informative) Exact one-twelfth-octave frequencies <\/td>\n<\/tr>\n | ||||||
| 37<\/td>\n | Table\u00a0H.1 \u2013 Exact frequencies for one-twelfth-octave steps over one decade <\/td>\n<\/tr>\n | ||||||
| 38<\/td>\n | Annex I (informative) Example calculations of expanded uncertainty of measurement <\/td>\n<\/tr>\n | ||||||
| 39<\/td>\n | Table\u00a0I.1 \u2013 Description of likely uncertainty components <\/td>\n<\/tr>\n | ||||||
| 40<\/td>\n | Table\u00a0I.2 \u2013 Uncertainty example for a frequency of 1\u00a0kHz <\/td>\n<\/tr>\n | ||||||
| 41<\/td>\n | Table\u00a0I.3 \u2013 Uncertainty example for a frequency of 8\u00a0kHz <\/td>\n<\/tr>\n | ||||||
| 42<\/td>\n | Bibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" Electroacoustics. Methods to determine corrections to obtain the free-field response of a sound level meter<\/b><\/p>\n |