Automotive Audio Testing Seminar

July 19th, 2022. 9.00am and 2.00pm Eastern US time (6.00am and 11.00am West Coast time)

In this practical online seminar, Steve Temme will demonstrate in-car measurement of frequency response, Max SPL, and Buzz, Squeak and Rattle using a Bluetooth connection. He will discuss considerations such as physical setup, infotainment system controls and the measurement parameters. Steve and his colleagues will then discuss connectivity for automotive testing, explaining and demonstrating the various connectivity options including USB drive, Bluetooth and A2B bus. Finally, we’ll take a look at some of the other audio measurements that you can make using SoundCheck, for example active noise cancellation and voice assistance readiness. 

Note: We will be repeating this seminar in conjunction with our exclusive distributor in China, S&V Samford, a sign-up will be available shortly.


Automotive Max SPL

The sequence measures the Max Sound Pressure Level (SPL) of a car infotainment system in the vehicle’s interior

The sequence uses a 6 microphone array mounted at either the driver or passenger locations. A 30 second pink noise stimulus having an RMS level of -12 dBFS is played through the infotainment system and captured by SoundCheck’s Multi-channel Real Time Analyzer (RTA). The Multi-channel RTA produces 6 RTA curves which are then power averaged to produce a Max SPL Spectrum. The spectrum is then power summed to produce a single value for Max SPL.


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.


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.


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.


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