Tag Archive for: test sequence

Automotive Test Sequence Including BSR, Max SPL and Frequency Response

We have a new automotive test sequence to measure Transient Distortion (also known as buzz, squeak, and rattle, Rub & Buzz, or impulsive distortion), Frequency Response, and Max SPL to the suggested measurement methods set out in the AES Technical Committee on Automotive Audio’s recently published white paper on in-car acoustic measurements. The three measurements are incorporated into one overall test sequence, making it fast and simple to run the entire suite of tests. This sequence facilitates evaluation of the committee’s proposals, and also serves as a basis for any similar in-house measurements. The white paper, which may be obtained from the TC-AA, outlines both measurement methods and physical configuration such as microphone and seat positioning in an effort to simplify comparison between vehicles.

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Complete End-of-Line Speaker Test (includes ePRB and eLP)

This sequence is an example of the many types of tests that can be performed quickly and simultaneously on a loudspeaker production line. A stepped sine sweep (StweepTM) from 20 kHz to 50 Hz is played through the speaker under test and measured via two channels of the audio interface. A calibrated reference microphone is connected to one of the channels and an impedance reference built into the SC Amp or AmpConnect is connected to the other. A HarmonicTrak™ Analysis step analyzes the recorded waveform from the reference microphone and outputs Frequency Response, THD, Normalized Rub & Buzz, Perceptual Rub & Buzz (ePRB), Loose Particle Prominence and Threshold (eLP) and Polarity. A Post-Processing step calculates the Average Sensitivity from 100 – 10kHz. A second Analysis step analyzes the recorded waveform from the impedance reference and outputs a curve of impedance versus frequency. A Post Processing step performs a curve fit of the impedance curve and calculates the max impedance (Zmax), precise resonance frequency (f0), and the quality factor (Q) of the resonance peak. All measurements and parameters are tested against limits in Limit steps. All these limits can be adjusted to suit your own DUT.

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RT60 Room Acoustics

The RT60 room acoustics sequence measures reverberation time and clarity of a room using multiple microphones to accurately characterize measurement environments. This is important for smart device testing as measurements of both speech recognition and audio output often need to be made in fully characterized rooms with known reverberation times and clarity. The method used in this sequence is fast, accurate, and made using fully calibrated signal paths. This sequence uses an omnidirectional speaker to play a Log Sweep from 250Hz – 15kHz and four microphones measure the impulse responses generated. These waveforms are analyzed using the Time Selective Response and room acoustics algorithms to calculate reverberation time (T20, T39, T60) and clarity (C7, C50 and C80) according to ISO 3382-1:2009.
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Background Noise Simulation to ETSI ES 202 396-1 Standard

Background_noise_simulation_screenshotThis Background Noise Simulation sequence follows the ETSI ES 202 396-1 standard.  It will automatically calibrate a standardized 4.1 speaker / subwoofer setup in accordance to the ETSI ES 202 396-1 standard “Loudspeaker Setup for Background Noise Simulation” and provide an equalized, calibrated playback solution to stress your device in a standardized and repeatable way.

Included with the sequence is a library of real world binaural recordings from the ETSI standard: cafeteria, pub, crossroad, vehicle, single voice distractor, and office noises.  Custom or user-defined  binaural recordings can also be used to create background noise tests directly applicable to your product. This sequence has many applications including evaluating ANC on headphones, noise  suppression on communication devices, voice recognition testing of smart speakers / IoT, SNR optimization of microphones on telepresence devices and beamforming directionality studies of microphone arrays.

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