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Simulated Free Field Measurements Without an Anechoic Chamber

In this online seminar, Steve Temme explains how to use simulated free field measurements to provide accurate free-field measurements across the entire audible frequency range without an anechoic chamber. This enables measurements that would usually be made in an anechoic chamber to be made in a regular lab or even home office – a valuable capability when so many are currently working from home.

This measurement method, which has been available in SoundCheck since 2001, measures the near-field response at low frequencies and the time-windowed far-field measurement at higher frequencies, and splices them together to provide the response over the entire frequency range.

This seminar explains the acoustics and mathematics behind this method, demonstrates the test procedure with the pre-written (and available free of charge) SoundCheck test sequence, and show how the results correlate to measurements made in an anechoic chamber.

Seminar topics include:

  • Discussion of sound paths and reflections and explaining the mathematic and acoustic principles behind simulated free field measurement techniques
  • Test set-up that can be used to measure this
  • Demonstration of the “Splice” sequence and measurements in SoundCheck
  • Correlation to results made in an anechoic chamber and manufacturer’s published data

Presenters: Steve Temme
Duration: 31 Mins

Resources for simulated free field measurements

Steve Temme and Christopher Struck authored a whitepaper for the AES on simulated free field measurements, available as PDF for further reading.

Our pre-written sequence demonstrated in this seminar for measuring the anechoic response of a loudspeaker without an anechoic chamber, or “Splice” sequence, is available for download from our sequence library

Check out our main page on Loudspeakers and Microspeakers, which includes links to test sequences, relevant products and more.

Basic Microphone Measurement Seminar

Technical Support Manager, Steve Tatarunis discusses and demonstrates basic microphone measurement, and how to measure characteristics that matter. Three different basic microphone test methods are explained including substitution, equalized source, and two-channel transfer function. Testing microphones in SoundCheck yields a full array of important results, since SoundCheck can be used to test microphone specifications including frequency response, sensitivity, impedance, directivity/polar pattern, polarity, dynamic range, signal to noise/self-noise, polarization/bias. Finally, two basic microphone measurement techniques are demonstrated: equalized source, and microphone substitution.

 

Seminar topics include:

  • Common microphone types and how they work
  • Microphone specifications
  • How to measure microphones using the two standard methods available in SoundCheck
    • Substitution method
    • Equalized speaker method
  • R&D and production test environments
  • Important measurements such as frequency response, sensitivity, etc.

Presenters: Steve Tatarunis
Duration: 34 Mins

Basic microphone measurement resources

Our sequence library is full of pre-written sequences for basic microphone measurement. Additionally, SoundCheck comes with many pre-written sequences including the sequences demonstrated in this seminar. To take these sequences to the next level, we offer more complex testing scenarios like microphone polar plot measurements with the new MDT-4000 turntable.

More about basic microphone measurement

Check out our main page on Microphones, which includes links to test sequences, relevant products and more.

Introduction to Headphone Testing Seminar

In this online seminar, Listen, Inc. founder and president, Steve Temme discusses basic headphone testing for both R&D and production environments. Aimed at the engineer new to headphone testing, he clearly explains how a headphone works, how to measure various types of headphones, equipment for both R&D and production test, and provides an overview of headphone measurement parameters. He concludes with a demonstration of a basic headphone measurement in SoundCheck.

  • How a headphone works
  • How to measure headphones (including considerations for different types of headphones, and acoustic ear simulators)
  • R&D and production test environments
  • Important measurements such as corrected frequency response, left/right tracking, distortion etc.

Seminar topics include:

  • How does a headphone work
  • Different types of headphones
  • Ear simulators
  • How to measure headphones
  • Acoustic test environments (R&D headphone test vs production headphone test)
  • Important headphone measurements
    • Frequency response
    • Distortion
    • Left / right tracking
    • etc.

Presenters: Steve Temme
Duration: 56 Mins

Headphone testing resources

Our pre-written sequence for basic headphone test can be found in the sequences folder of your SoundCheck installation.

We also offer other pre-written headphone tests such as a sequence for measuring Active Noise Cancellation and a test sequence for testing stereo headphones connected to a portable audio device using open loop measurements.

Measuring to headphone standards such as IEC 60268-7 is also an out-the-box measurement with SoundCheck and our pre-written test sequence. More information about the ANSI IEC 60268-7 standard can be found from the official ANSI site.

More about headphone testing

Check out our main page on Headphone and Headset tests, which includes links to test sequences, relevant products and more.