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.
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.
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 Years of Audio Measurement: A Retrospective
Author: Steve Temme. Reprinted from the 2020 Loudspeaker Industry Sourcebook.
In this article, as Listen celebrates its 25th anniversary, Steve Temme reflects on 25 years in the audio test and measurement business.
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!
Waveform Windowing
This sequence demonstrates how SoundCheck’s Windowing post-processing function is applied to waveforms to remove measurement artifacts that might otherwise create false auto delay values and subsequent analysis errors.
This sequence uses data from a customer who was measuring the directivity of a hearing aid-type device by mounting it on a rotating HATS and using a short duration log sweep. The DUT does not have a perfect seal in the HATS ear and the devices signal processing produces a latency of around 35ms. When viewing the Recorded Time waveforms, both the leakage signal and the amplified signal can be seen. As the DUT approaches 180° the magnitude of the leakage into the HATS ear exceeds that of the amplified signal, creating false Record Delay values and subsequent analysis errors. This sequence applies a window to the Recorded Time Waveform to remove the early-arrival leakage, and calculates the true Record Delay values of the amplified signal, obtaining consistent analysis results at all angles of rotation. This sequence can be adapted to your other requirements, for example, removing early arrival signals from a waveform or editing out excessive delay in a waveform.
