Technical Resources
With over 100 combined years of audio measurement experience, our team has created a wealth of technical papers, sequences, articles and other useful information to assist you with your audio test needs. Please browse the collection below, or filter by type of resource.
How to Measure Free Field Speaker Response without an Anechoic Chamber
Did you know
you can make free-field measurements without an anechoic chamber? In the March 2021 issue of VoiceCoil, Steve Temme explains his unique method for achieving this. The article explains how the ‘splice’ method results in a full range frequency response from a combination of near-field and windowed far-field measurement, and compares the results with anechoic chamber measurements and the manufacturer’s published response curve.
Anechoic Response of a Loudspeaker Without an Anechoic Chamber: Splice Sequence
This sequence measures the anechoic response of a loudspeaker in an ordinary room using both a near field and time-windowed far field measurement “spliced” together to cover the full bandwidth of the loudspeaker’s response from 20 Hz to 40 kHz. First, the microphone is placed very close to the low frequency driver (less than an inch from the woofer), and the near field frequency response measured using a 1/12th octave stepped sine). Next, the microphone is placed in the far field and the frequency response is measured using a continuous log sweep with the Time Selective Response analysis algorithm. An option is available for measuring a ported loudspeaker. The sequence displays both measurements on a graph, showing the overlap range where the measurements are equal. From this, the user selects the precise frequency at which to splice the two halves of the measurements together to obtain the full range free field response of the loudspeaker.
Listen Celebrates 25 Years
2020 is Listen’s 25th anniversary! When Listen sold its first product in 1995, it was the first soundcard-based audio measurement system, and its competition was often human listeners. Now, with an installed base of well over 10,000 systems and the industry-wide adoption of both soundcard-based architecture and highly automated sequence-based measurement, Listen is still leading the way with new algorithms and product development to meet the changing needs of the marketplace. In this article, reprinted from Loudspeaker Industry Sourcebook, Listen founder and president, Steve Temme, shares his story.
Comparison of Effect of Different Masks on Speech Distortion
The purpose of this sequence is to compare the response of an artificial mouth when face masks of different construction are mounted on the mouth. The sequence assumes a lightweight disposable mask and a heavy multi-layer cloth mask. A stepped sinewave from 10 kHz – 100 Hz is played from the unoccluded mouth and the operator is then prompted to mount and measure the two masks over the mouth. The three mouth responses are then displayed on one x-y graph and the difference curves (unoccluded mouth vs masked mouth) are displayed on another. Finally, the average attenuation created by each mask across the measurement range is displayed on a table.
Note that the curve names are constructed by selecting the “Use Input Data Name” option on the Curves tab of the Analysis editors. The appended text in parentheses (No Mask, Disposable Mask, Cloth Mask) comes from the custom naming of the three Recorded Time Waveforms so if you wish to edit these, it can be done by editing the Waveform names in the Acquisition steps.
Statistics Tutorial
Our series of instructional training videos continues with this series of 4 short videos explaining Statistics. These introduce the user to the statistics options in SoundCheck, and demonstrate how to use them in 4 different ways: in sequences, with results, Process Capability measurements, and offline statistics.
Statistics 1: Data
Statistics 2: Results
Statistics 3: Process Capability
Statistics 4: Offline
25: Confidence Limits (working from home with SoundCheck)
Following questions from some SoundCheck users who had watched #3 in this series (sequence optimization), Steve Tatarunis takes a look at the measurement confidence function in SoundCheck, and explains the trade-offs between speed and accuracy when choosing a step size to optimize your measurement.
24: Instrument Highlights (working from home with SoundCheck)
Anastassia Tolpygo demonstrates some neat features of virtual instruments that you may not have seen before. These enable you to make a quick distortion measurements, accurately measure frequencies at very high resolution, and plot and save curves over time using just the virtual instruments without the need for a sequence step.
23: Offline Statistics (working from home with SoundCheck)
In this short video, Steve Tatarunis takes a deeper dive into the Offline Statistics functionality in SoundCheck, demonstrating how you can run statistical analyses from home on data from your production facility or overseas contract manufacturer. No hardware required – just your computer with SoundCheck and some measured data!
