Technical Notes
A collection of technical notes and tutorials written or presented by Listen employees and colleagues.
Testing Voice-Controlled & Smartphone Integrated Infotainment Systems
/in Papers, Technical Notes /by ZarinaA tutorial and accompanying paper on testing infotainment systems that was presented at the AES Automotive Conference, Sept 11-13, 2019, Neuburg an der Donau, Germany. Voice-controlled and smartphone integrated vehicle infotainment systems are notoriously complex to test. They have numerous connections from wired to wireless and contain much signal processing, both on the record and […]
Harmonic Distortion Measurement: The effects of sampling rate and stimulus frequency on the measured harmonic frequency (including THD and Rub & Buzz)
/in Technical Notes /by ZarinaAuthor: Steve Temme Harmonic distortion measurements can be confusing to interpret, and it’s important to understand the data that you are looking at, particularly the relationship between the stimulus frequency and the measured harmonic frequency. This brief guide explains the relationships between sampling rate, stimulus frequency and measured harmonics for both normalized and conventional harmonic […]
Practical Impedance Measurement
/in Technical Notes /by ZarinaAuthor: Steve Temme Loudspeaker impedance measurements are made for many reasons. In the R&D lab, these range from the simple task of identifying a speaker’s resonant frequency to more complex functions such as calculating the speaker’s Thiele-Small parameters. On the production line, impedance measurement is a key quality control parameter that verifies that the speaker’s […]
Audio Test Stimuli – An Overview
/in Technical Notes /by ZarinaAuthor: Steve Temme Most audio analysis systems offer a wide range of stimulus option, and selecting the right one can be daunting. This overview explains the different stimulus types, what the waveforms look and sound like (click the speaker icon to hear the sound), the advantages and disadvantages of each and when you would be […]
Headphone Testing – a comprehensive overview
/in Technical Notes /by ZarinaAuthor: Steve Temme and Brian Fallon With the headphone market growing towards $10 billion worldwide, and products across the price spectrum from under a dollar up to thousands, there are many and diverse quality expectations and test requirements. Many audio engineers have moved across from the shrinking loudspeaker industry to the burgeoning headphone marketplace. Although […]
ESCORT: The Listen Guide to Audio Troubleshooting
/in Technical Notes /by ZarinaAuthor: Steve Temme Audio test troubleshooting comes down to 5 things: Environment, Setup, Calibration, Organization, Range and Technique. In this article we discuss each of these areas of potential problems and provide suggestions for troubleshooting any audio testing setup, regardless of application. We also provide general hints and tips to improve your audio testing configuration. […]
The Challenges of MP3 Player Testing
/in Technical Notes /by ZarinaAuthor: Steve Temme MP3 players have been the ‘must-have’ electronic gadget for the past few years. Over 10 million players were sold in 2005, and this is predicted to rise to more than double this by 2010. But how can manufacturers carry out QA tests on the production line, ensure excellent sound quality and demonstrate […]
HarmonicTrak Algorithm for Fast and Accurate Swept Sine Measurement
/in Technical Notes /by ZarinaAuthor: Steve Temme The sine generator in SoundCheck®, operates on the same principles as a traditional swept sine measurement system consisting of a sine generator, voltmeter, tracking filter, and level recorder. The main difference is that it is implemented in the software as a virtual instrument. The SoundCheck sine generator sweeps in discrete steps; each […]
Are You Shipping Defective Loudspeakers to your Customers?
/in Technical Notes /by ZarinaAuthor: Steve Temme Loudspeaker distortion is undesirable. The type and level of distortion, however, can greatly influence the perceived annoyance. In addition, identifying the type of distortion can also help pinpoint the mechanism or mechanisms in the loudspeaker that are causing the distortion. “Rub & Buzz” is a good example of a particularly annoying type […]
Evaluation of Loudspeaker Performance at Low Frequencies
/in Technical Notes /by ZarinaAuthors: Steve Temme and Christopher J Struck Evaluation of loudspeaker performance at low frequencies is complicated by long wavelengths, room interaction and cabinet/baffle diffraction. Since low frequency measurements have traditionally required large, impractical testing environments, different techniques have been developed in an attempt to overcome this requirement. Anechoic chambers, outdoor measurements, half-space measurements, ground plane […]
Audio Distortion Measurements
/in Technical Notes /by ZarinaAuthor: Steve Temme In the never ending quest for better sound transmission, reinforcement, and reproduction, the electronics have been extensively analyzed for distortion. Distortion in the electroacoustic transducers, while typically several orders of magnitude greater, has often been neglected or not even specified because it has been difficult to measure and interpret. With a basic […]
Time Selective Measurements with a Logarithmically Swept Sine
/in Technical Notes /by ZarinaAuthor: Martin Rung A time selective measurement of a frequency response is (directly or indirectly) based on a measurement of the impulse response, where a well-defined time window is applied to the impulse response. The frequency response is simply the Fourier transform of the impulse response. Time selective measurements are often used in electroacoustics to […]
