刊发文章
由Listen员工及同行发表的一系列文章
Advances in Impedance Measurement of Loudspeakers and Headphones
/在： Papers /通过： ZarinaImpedance measurement is often the sole electrical measurement in a battery of QC tests on loudspeakers and headphones. Two test methods are commonly used, single channel and dual channel. Dual Channel measurement offers greater accuracy as both the voltage across the speaker (or headphone) and the reference resistor are measured to calculate the impedance. Single […]
Measurement of Harmonic Distortion Audibility Using A Simplified Psychoacoustic Model – Updated
/在： Papers /通过： ZarinaA perceptual method is proposed for measuring harmonic distortion audibility. This method is similar to the CLEAR (Cepstral Loudness Enhanced Algorithm for Rub & buzz) algorithm previously proposed by the authors as a means of detecting audible Rub & Buzz which is an extreme type of distortion[1,2]. Both methods are based on the Perceptual Evaluation […]
Measurement of Harmonic Distortion Audibility Using A Simplified Psychoacoustic Model
/在： Papers /通过： ZarinaA perceptual method is proposed for measuring harmonic distortion audibility. This method is similar to the CLEAR (Cepstral Loudness Enhanced Algorithm for Rub & buzz) algorithm previously proposed by the authors as a means of detecting audible Rub & Buzz which is an extreme type of distortion[1,2]. Both methods are based on the Perceptual Evaluation […]
Practical Implementation of Perceptual Rub & Buzz Distortion and Experimental Results
/在： Papers /通过： ZarinaIn a previous paper [1], we demonstrated how an auditory perceptual model based on an ITU standard can be used to detect audible Rub & Buzz in loudspeakers using a single tone stimulus. In this paper, we discuss a practical implementation using a stepped sine sweep stimulus and present detailed experimental results on loudspeakers including […]
Practical Measurement of Loudspeaker Distortion Using a Simplified Auditory Perceptual Model
/在： Papers /通过： ZarinaManufacturing defects in loudspeaker production can often be identified by an increase in Rub & Buzz distortion. This type of distortion is quite noticeable because it contributes an edgy sound to the reproduction and is annoying because it often sounds separate or disembodied from the fundamental signal. The annoyance of Rub & Buzz distortion is […]
Evolution of Time-Frequency Analysis Methods and their Practical Applications
/在： Papers /通过： ZarinaTime-Frequency analysis has been in use for more than 20 years and many different Time-Frequency distributions have been developed. Four in particular, Short Time Fourier Transform, Cumulative Spectral Decay, Wavelet and Wigner-Ville have gained popularity and firmly established themselves as useful measurement tools. This paper compares these four popular transforms, explains their trade-offs and discusses […]
Challenges of MP3 Player Testing
/在： Papers /通过： ZarinaMP3 player audio performance is discussed including measurements of frequency response, phase response, crosstalk, distortion, sampling rate errors, jitter, and maximum sound pressure level with headphones. In order to make these measurements, several measurement techniques and algorithms are presented to overcome some of the challenges of testing MP3 players. We discuss test equipment requirements, selection […]
A New Method for Measuring Distortion using a Multitone Stimulus and Non-Coherence
/在： Papers /通过： ZarinaA new approach for measuring distortion based on dual-channel analysis of non-coherence between a stimulus and response is presented. This method is easy to implement, provides a continuous distortion curve against frequency, and can be used with a multitone stimulus, noise, or even music. Multitone is a desirable test signal for fast frequency response measurements […]
Higher Order Harmonic Signature Analysis for Loudspeaker Defect Detection
/在： Papers /通过： ZarinaLoudspeaker assembly faults, such as a rubbing voice coil, bent frame, loose spider, etc., have traditionally been detected using experienced human listeners at the end of a production line. Previous attempts to develop production measurement systems for on-line testing typically analyze only low-order harmonics for the primary purpose of measuring total harmonic distortion (THD), and […]
Enhancements for Loose Particle Detection
/在： Papers /通过： ZarinaDuring loudspeaker production, particles may become trapped in the loudspeaker motor and voice coil vicinity, resulting in a distinctive defect that is easily heard, but difficult to detect by traditional test and measurements. We found that a Sine Sweep Stimulus followed by a High Pass Filter and RMS Envelope Analysis efficiently detected Loose Particles and […]
Loose Particle Detection
/在： Papers, 未分类 /通过： ZarinaDuring the loudspeaker manufacturing process, particles may become trapped inside the loudspeaker, resulting in a distinctive defect that is easily heard but difficult to measure. To give a clearer view of the problem, Time-Frequency maps are shown for some defective loudspeakers. Based on this analysis, a reliable testing procedure using a swept-sine stimulus, high-pass filter, […]
Simultaneous measurement of impulse response and distortion with a swept-sine technique
/在： Papers /通过： ZarinaThis landmark paper by Angelo Farina discusses the benefits of the Log Sine Sweep (also known as Frequency Log Sweep or Log Chirp), one of the test signals available in SoundCheck. A novel measurement technique of the transfer function of weakly not-linear, approximately time-invariant systems is presented. The method is implemented with low-cost instrumentation; it […]
Virtual Instruments for Audio Testing
/在： Papers /通过： ZarinaAlthough Virtual Instruments have been part of SoundCheck as long as most of us can remember, back in 1998 this was a huge innovation. This paper introduces the concept at a time when computerized audio measurement was a novel concept. Authors: Steve Temme Presented at the 105th AES Convention, San Francisco, 1998 Full Paper
How to Graph Distortion Measurements
/在： Papers /通过： ZarinaDistortion curves are conventionally plotted under the corresponding excitation frequency of the measured fundamental. Interpretation of results can be misleading due to the influence that the passband shape and amplitude irregularities of the fundamental response have on the distortion responses. By ‘amplitude normalizing’ the distortion responses to the measured fundamental response before plotting them at […]
Simulated Free Field Measurements
/在： Papers /通过： ZarinaThe development of time selective techniques has enabled measurements of the free field response of a loudspeaker to be performed without the need for an anechoic chamber. The low frequency resolution of both time selective techniques and anechoic measurements is, however, limited by the size of the room. A technique is presented enabling measurements of […]
