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ELECTRO-ACOUSTIC TEST. AP PERFORMANCE.


Complete Acoustic Test

APx audio analyzers are the preferred choice for designing and testing soundbars, pro-audio powered speakers, smartphones, handsfree devices and other products that integrate electronics and loudspeakers. For production test of drivers as well as finished products, manufacturers trust AP for the high reliability of our hardware and the ease-of-use of our software.


APx Electro-Acoustic tests are available as software options for APx500 in both R&D and Production editions.

 

Measurements

 

Accessories and Additional Information

 

 

APx Impedance/Thiele-Small Characterization

TS

The APx Impedance/Thiele-Small measurement captures the complex impedance of a loudspeaker under test and delivers calculated electromechanical parameters that define the low frequency performance of loudspeaker drivers, allowing designers of integrated audio products to focus on complete product engineering with a single instrument.

 

Thiele-Small results accurately describe the interactions between loudspeaker and enclosure, and are vital to both loudspeaker system design and production test. Once a system is designed, any measured deviation from expected Thiele-Small results can quickly identify defects in manufacturing or parts quality.

 

APx Thiele/Small supports the Known Mass, Known Volume and Added Mass methods. Added Mass and Known Volumes methods deliver accurate parameters using two-pass measurements, while Known Mass allows complete Thiele-Small characterization in a single pass.

 

 

 

APx Loudspeaker Production Test

Golden Unit

The APx Loudspeaker Production Test option provides a multi-parameter check of all key loudspeaker performance metrics with incredible speed and ease of use. With a single 1 second sweep, the APx Loudspeaker Production Test option compares selected Thiele-Small parameters with expected results to ensure driver and enclosure integrity, and simultaneously checks for Rub & Buzz defects, Polarity, Relative Level, Phase, Distortion Product Ratio, and Distortion Product Level.

  • Golden Unit comparison
  • Rub & Buzz detection
  • Complete evaluation with 1-second sweep

Combined with AP’s automation, project sharing and complete audio electronics test, APx is truly comprehensive Production test platform for all integrated audio devices

 

 

 

APx Rub & Buzz

Rub & Buzz

APx Rub & Buzz finds defects characterized by a high crest factor in combination with a high peak ratio when driven by a chirp stimulus. These defects include misaligned voice coils, particles in the voice coil gap, and incomplete adhesion of suspension elements to a frame. In these cases, the resulting artifacts are very transient in nature, and while very difficult to detect using standard techniques such as FFT, the human ear is exceedingly sensitive to these noises.


When combined with the full automation of APx, drivers in production environments may easily be evaluated for pass/fail using a single encompassing test sequence.

 

 


Waterfall and Polar Plots

Waterfall and Polar

The Electro-Acoustic Test R&D edition provides powerful visualization tools for understanding electro-acoustic behavior.

 

APx Waterfall Plot creates three-dimensional graphs that display multiple curves of data that can represent changes over time or frequency. Spectrum or Cumulative Spectral Decay (CSD) views are available, with variable FFT length, number of slices and samples per shift.

 

APx Polar Plot displays the response of loudspeakers and microphones relative to position in a plane, and supports multiple brands of turntables to produce full circle, semi-circle, quarter-circle and custom plots.

 

Supported Turntables for Polar Plots

  • LinearX LT360EX
  • Outline ET250-3D

 

APx Modulated Noise Air Leak Detection

Modulated Noise Results

APx Modulated Noise measurement models air leak defects as a type of weighted white noise that is modulated by a low frequency stimulus, reliably detecting leaks in enclosures due to poor seals, open jacks or construction issues.

 

Air leaks can degrade the performance of loudspeakers, impacting design parameters and generating unwanted noise artifacts that are exceedingly difficult to detect with standard measurements, often buried in a noise floor.

 

As compact integrated audio products push the boundaries of sound pressure and bass response, enclosure integrity is increasingly a problem that must be tested to ensure quality. Product-mounted controls and jacks compound the difficulties of creating leak-free enclosures, making the APx Modulated Noise Air Leak measurement an essential part of the electro-acoustic designer's toolkit.

 

 

 

 

APx Other Acoustic Measurements

APx ETC Curve

APx automatically calculates all the key acoustic response measurements including level, frequency response, phase, distortion, and group delay. In all, 14 graphed measurements are returned. In addition, APx offers synchronous averaging and Nth-octave smoothing. The results are available on screen, can be printed to PDF or exported in table format for use in other applications. Like all APx measurements, acoustic response can be part of a larger test sequence or controlled externally from an application such as LabVIEW.

 

 

 

 

 

 

Easy Test Setup

APx Acoustic Distortion graph

Setting up acoustic test in non-anechoic spaces is challenging because sound reflections from the walls and floor interfere with the measurement. Like other non-anechoic acoustic test solutions, APx uses a time-gated logarithmic sweep to measure the impulse response of the acoustic device. Unlike other solutions however, AP’s interface for defining the time gate is fast and easy: users simply drag a cursor over the impulse response graph or energy time curve and APx recalculates all the derived measurements in real time.

 

 

APx Loudspeaker Impedance Fixture IMP1

IMP1

The APx IMP1 Loudspeaker Impedance Fixture provides multiple methods for connecting and measuring loudspeaker drivers, with and without the use of external amplifiers.  The IMP1 is a convenient addition to your test bench, with selectable connection topology and a choice of 0.1 ohm and 1.0 ohm series sense resistors.

 

 

 

 

Demonstration Video

The video below shows how APx Acoustic Measurements work in a real lab setting.



How to Buy APx Electro-Acoustic Test Software Options

The APx Electro-Acoustic test suites are available as software option packages. Each option delivers features tailored to the specific needs of R&D (APX-SW-SPK-RD) or production (APX-SW-SPK-PT) for optimal performance and results. For more information about purchase, please contact your AP sales representative.

 

 

  • R&D: APX-SW-SPK-RD
  • Impedance/Thiele-Small characterization
    Impedance Real
    Impedance Imaginary
    Impedance Magnitude
    Impedance Phase
    Thiele-Small Parameters
  • Acoustic Response
    Rub & Buzz Detection
    Impulse Response
    Frequency Response
    Energy Time Curve
    Relative Level
    Phase
    Distortion Product Ratio
    Distortion Product Level
  • Loudspeaker Production Test
    Selected Thiele-Small Parameters
    Impedance Magnitude
    Impedance Phase
    Frequency Response
    Relative Level
    Phase
    Polarity
    Distortion Product Ratio
    Distortion Product Level
    Rub & Buzz Detection
  • Modulated Noise Air Leak Detection
  • Production: APX-SW-SPK-PT
  • Loudspeaker Production Test
    Selected Thiele-Small Parameters
    Impedance Magnitude
    Impedance Phase
    Frequency Response
    Relative Level
    Phase
    Polarity
    Distortion Product Ratio
    Distortion Product Level
    Rub & Buzz Detection
  • Modulated Noise Air Leak Detection



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