CHAPTER 5

SIM MEASUREMENT SYSTEM

The SIM audio analyzer is a measurement and instrumentation system including a selection of hardware and software options, microphones and accessory cables. The SIM 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 Meyer Sound's 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

Applications

The main application of the SIM audio analyzer 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

The SIM audio analyzer 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

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