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Measuring Max SPL versus Frequency

This sequence measures the Max SPL of a transducer versus frequency that a device can play back with acceptable distortion. It is particularly valuable for designers using DSP algorithms to optimize the performance of their speakers.

It characterizes the Max SPL of a transducer by setting limits on specific metrics (THD, Rub & Buzz, Perceptual Rub & Buzz, Input Voltage and Compression) and then driving the transducer at a series of standard ISO frequencies, increasing the stimulus level until the one of the limits is surpassed. The sequence begins by measuring the frequency response and impedance of the DUT. The user is asked if they wish to use the -3dB from resonance frequency as the test Start Frequency or manually enter another value. The user is then prompted to enter a Stop Frequency, initial test level and limit values for the metrics of interest. The sequence then plays the stimulus Start Frequency in a loop, increasing the level +3dB with each loop iteration until one of the limits is exceeded.  The stimulus level is then adjusted -3dB and the sequence continues to a second loop which increases the stimulus level +0.5 dB with each loop iteration until the limit is exceeded. At this point, the limit results are saved to an Excel file, the stimulus frequency is incremented by a constant multiplication step and the process is repeated until the Stop Frequency is achieved. Every time the main loop is completed, the individual SPL and Stimulus Level x-y pairs are concatenated to master curves. At the end of the sequence, the Max SPL and Stimulus Level curves are autosaved in .dat format.

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EN 50332-1 – Max. SPL of Portable Audio Devices

EN-50332_1 screenshotThis sequence follows the test standard detailed in EN50332-1 (2013) for measuring the maximum sound pressure for portable music players and the earphones/headphones they are bundled with. The test involves loading a weighted pink noise stimulus file (as specified by IEC 268) onto the portable device and playing it through the earphones at the player’s maximum volume.

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EN-50332-2: Measuring SPL of Portable Devices

EN50332_screenshotThese two sequences follow the test standard detailed in EN50332-2 for measuring the maximum levels of portable music players and earphones/headphones. This section of the standard covers the individual testing of the devices rather than the combined testing that is detailed in part 1. Note that the physical setup and connections will be different between the two sequences. Please read the hardware and calibration sections of this instruction carefully.

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Headphones and EN50332

This webinar discusses the setup and execution of the EN-50332 standard sequence package for SoundCheck.  This standard outlines procedures for measuring the maximum output of headphones and portable music players. Presented by Brian Fallon, Listen, Inc. Status: Recorded. Watch Webinar