Triggered Record Using WAV File (Version 16.0 and earlier)

triggered_record_screenshotThis sequence allows you to test devices without an analog input such as tablets, cellphones and MP3 players. A stimulus WAV file is created in SoundCheck, and copied to the device under test, where it is played and the response recorded in SoundCheck as if the stimulus were played directly from SoundCheck. The stimulus WAV file to be used on the device under test (DUT) may be customized in the stimulus step.

Note that this sequence uses the level-based trigger available in SoundCheck 16.0 and earlier. If you are using version 16.1 or later, please see the frequency-trigger based sequence which takes advantage of new functionality to offer more robust triggering.

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Thiele-Small Parameters

Loudspeaker system performance can be quantitatively related to a set of electro-mechanical parameters. These parameters are known in the industry as Thiele-Small parameters. They were first introduced by A.N.Thiele and Richard H.Small in a series of famous articles published in the 1971-72 Journal of AES (Audio Engineering Society).  Over the years these parameters have become standards in the industry, and are used by loudspeaker designers worldwide. This package contains SoundCheck sequences for measuring measuring Thiele-Small Parameters by Added Mass, Known Volume, Known Driver Mass methods.

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Impedance Measurement – Dual Channel Method Using Math Post-Processing

Impedance_measurement_math_postprocessing_outputThis sequence demonstrates an alternative to the traditional SoundCheck single channel impedance measurement method. A stepped sine sweep from 20 Hz to 20 kHz is played through the speaker while the signal across the loudspeaker terminals is recorded by Direct In 1 and the signal across the sense resistor (impedance box) is recorded by Direct In 2. A heterodyne analysis step is then applied to calculate the fundamental response from both inputs and a math post-processing step divides Fundamental A (speaker terminal voltage) by Fundamental B (voltage across sense resistor). A post-processing step corrects for the value of the reference resistor before displaying the final impedance curve. The curve is then post-processed to calculate resonance frequency, maximum impedance and Q of the resonance peak.  A set of arbitrary limits steps are also provided to generate pass/fail results.

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Perceptual Rub & Buzz

Perceptual Rub & Buzz ScreenshotThis sequence uses the CLEAR algorithm for perceptual Rub & Buzz measurement to detect AUDIBLE Rub & Buzz. It uses a simplified auditory perceptual model to measure the loudness of Rub & Buzz distor­tion in phons rather than the more traditional dB SPL and % distortion units. These better identify whether distortion due to manufacturing defects can be heard by the listener than conventional measurements. In addition to a result which corresponds more accurately to the human ear, this new test method also offers two significant advantages for use on the production line. It is less sensitive to transient background noises than traditional methods, therefore is reliable in noisy environments, and it is much simpler to set limits than when us­ing conventional distortion measurements. The sequence includes saved data that can be loaded from disk, so even if you don’t have a speaker handy you can still listen to the wav. file and see how SoundCheck displays the data.

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Impedance Measurement – Dual Channel Method Using Transfer Function

Impedance measurement - dual channel using transfer functionThis sequence demonstrates an alternative to the traditional SoundCheck single channel impedance measurement method. A white noise stimulus (10 Hz – 10 kHz) is played through the speaker while the signal across the amplifier terminals is recorded by Direct In 1 and the signal across the impedance box is recorded by Direct In 2. A transfer function analysis step is then applied to the recorded time waveforms to calculate the impedance curve. Subsequent post processing steps apply a frequency window, 1/24th octave smoothing and 1/24th octave resolution to the impedance curve. The curve is then post-processed to calculate resonance frequency, maximum impedance and Q of the resonance peak. A set of arbitrary limits steps are also provided to generate pass/fail results. The final display shows the post processed impedance curves and results window.

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Loudspeaker Splice Test Sequence

Loudspeaker Splice Sequence ScreenshotThe purpose of this sequence is to measure 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 to 40 kHz.
First, the near field frequency response is measured using a 1/12th octave stepped sine sweep by placing the microphone very close to the low frequency driver (less than an inch from the woofer). Then the far field frequency response is measured using a continuous log sweep with the Time Selective Response analysis algorithm.

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Ported Loudspeaker Splice Test Sequence

Ported Splice Sequence Screenshot

Ported Splice Sequence Screenshot

This loudspeaker splice 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 to 40 kHz. It can accommodate ported as well as sealed loudspeakers.
First, the near field frequency response is measured using a 1/12th octave stepped sine sweep by placing the microphone very close to the low frequency driver and the port(s) if any. Then the far field frequency response is measured using a continuous log sweep with the Time Selective Response analysis algorithm.

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