ANSI S1.9 : 1996

Foreword
0 Introduction
1 Scope
2 Purpose
3 Applications
4 References
   4.1 Normative references
   4.2 Other related references
5 Definitions
   5.1 Sound intensity probe
   5.2 p-p probe (also known as the two-microphone probe)
   5.3 Reference point of probe
   5.4 Reference axis
   5.5 Reference direction
   5.6 Phase difference between probe channels for a p-p probe
   5.7 Nominal separation of microphones in a p-p probe
   5.8 Sound-intensity processor
   5.9 Sound-intensity instrument
   5.10 Residual intensity
   5.11 Pressure-residual-intensity index, delta[pl 0]
   5.12 Mean-pressure level
   5.13 Standing-wave ratio
   5.14 Operating range
   5.15 Real-time operation
   5.16 Phase-difference compensation
   5.17 Autoranging
   5.18 Sound-pressure calibrator
   5.19 Pressure-residual-intensity testing device
   5.20 Sound-intensity calibrator
   5.21 Type test
   5.22 Verification
   5.23 Initial verification
   5.24 Periodic verification
6 Instrument systems - requirements
   6.1 General
   6.2 Principle of operation
   6.3 Accuracy
   6.5 Filtering
   6.6 Sound-intensity level indicator accuracy
   6.7 Provision for probe-microphone-separation distance
   6.8 Presentation of results
   6.9 Directional response
   6.10 Time averaging
   6.11 Crest factors
   6.12 Provision for phase compensation
   6.13 Provision for range setting
   6.14 Provision for overload indication
   6.15 Provision for correction for atmospheric pressure and
        temperature
   6.16 operating environment
   6.17 A-weighting
   6.18 Performance in a standing-wave field
   6.19 Power supplies
7 Processors - requirements
   7.1 General
   7.2 Principle of operation
   7.3 Frequency range
   7.4 Accuracy
   7.5 Filtering
   7.6 Sound-intensity level indicator accuracy
   7.7 Provision for microphone-separation distance
   7.8 Presentation of results
   7.9 Time averaging
   7.10 Crest factors
   7.11 Provision for phase compensation
   7.12 Provision for range setting
   7.13 Provision for overload indication
   7.14 Provision for correction for atmospheric pressure
        and temperature
   7.15 Operating environment
   7.16 A-weighting
   5.17 Power supplies
8 Sound-intensity probes - requirements
   8.1 General
   8.2 Frequency range
   8.3 Accuracy
   8.4 Directional response of the probes
   8.5 Probe performance in standing waves
9 Tests to verify the performance characteristics of the
   measurements systems, processors, and probes
   9.1 General
   9.2 Octave and one-third octave filters (instrument
        systems and processors)
   9.3 Sound-intensity level indication (systems and
        processors)
   9.4 Probe-microphone-separation setting (systems
        and processors)
   9.5 Time-averaging characteristics (systems and
        processors)
   9.6 Crest-factor handling test (systems and processors)
   9.7 Pressure-residual-intensity index and operating
        range of the processors and instrument systems
   9.8 Pressure-residual-intensity index of the probes and
        the instrument systems
   9.9 Frequency response (probes and instrument systems)
   9.10 Directional response (probes and instrument systems)
   9.11 Probe-performance verification in a standing-wave
        field (probes and instrument systems)
10 Sound-intensity probe calibrators
   10.1 General requirements
   10.2 Performance verification
11 Nameplate data and instruction manual
   11.1 Nameplate data
   11.2 Instruction manual information
Annex A - Periodic verification tests
Annex B - Sound-intensity instruments based on FFT analyzers
Tables
Figures

Applicable to instruments that determine sound intensity by a two-microphone probe, having a pair of spatially separated pressure-sensing microphones.