Sim Measurement System; Source Independent Measurement Technique; Applications - Meyer Sound M SERIES Operating Instructions Manual

CHAPTER 6

SIM MEASUREMENT SYSTEM

SIM is a measurement and instrumentation system
including a selection of hardware and software options,
microphones and accessory cables. The SIM audio analyzer
is optimized for making audio frequency measurements of
an acoustical system with a resolution of up to 1/24 of an
octave; the high resolution enables you to apply precise
electronic corrections to adjust system response using
frequency and phase (time) domain information.

Source Independent Measurement Technique

The SIM audio analyzer implements the Meyer Sound
source independent measurement technique, a dual-
channel method that accommodates statistically
unpredictable excitation signals. Any excitation signal
that encompasses the frequency range of interest (even
intermittently) may be used to obtain highly accurate
measurements of acoustical or electronic systems. For
example, concert halls and loudspeaker systems may be
characterized during a musical performance using the
program as the test signal, allowing you to:
■ View measurement data as amplitude versus time
(impulse response) or amplitude and phase versus
frequency (frequency response)
■ Utilize a single-channel spectrum mode
■ View frequency domain data with a logarithmic
frequency axis
■ Determine and internally compensate for propagation
delays using SIM Delay Finder function
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Applications

The main application of SIM is loudspeaker system testing
and alignment. This includes:
■ Measuring propagation delay between the subsystems
to set correct polarities and set very precise delay times
■ Measuring variations in frequency response caused
by the acoustical environment and the placement
and interaction of the loudspeakers to set corrective
equalization
■ Optimizing subwoofer integration
■ Optimizing loudspeaker arrays
SIM can also be used in the following applications:
■ Microphone calibration and equalization
■ Architectural acoustics
■ Transducer evaluation and correction
■ Echo detection and analysis
■ Vibration analysis
■ Underwater acoustics