Noise

About: Noise is a research topic. Over the lifetime, 5111 publications have been published within this topic receiving 69407 citations. The topic is also known as: Мопсы танцуют под радио бандитов из сталкера 10 часов.

Active Control System for Low Frequency Road Noise Combined with an Audio System

Abstract: An active control system for low-frequency road noise in automobiles combined with an audio system is developed as a commercial application for the first time in the world, and installed in a station wagon. The purpose of this paper is to provide an outline of the system and describe the newly developed cost-reduction technology used for it, since the reduction of system costs is a major reason that active noise control technology could successfully be applied in a commercial product. The methods used to reduce costs include utilization of feedback control, implementation by analogue circuits, and common use of audio system speakers. This system reduces low-frequency road noise in the front seat by about 10 dB and improves audio system listening experience while driving.

Speech enhancement based conceptually on auditory evidence

Abstract: A new idea, enhancing speech based on auditory evidence, is explored for the problem of enhancing speech degraded by stationary and nonstationary additive white noise. Distinguishing different objectives for heavy and light noise interference, two related algorithms are developed. For speech degraded by heavy noise, the improvement in signal-to-noise ratio (SNR) is as high as 12 dB; for lightly noisy speech, the improvement is modest and decreases as the SNR of the noisy speech increases. Quantizing noise is used to assess the capacity for reducing nonstationary noise using these algorithms; a significant reduction of such noise and an improvement in speech quality are achieved. The advantages of the proposed algorithms for speech enhancement include no need for prior knowledge of the noise and only a modest computational requirement. >

Adaptive noise canceller

Abstract: An adaptive filter estimates the noise component in a primary audio signal by convolving a secondary audio signal with a set of coefficients. The estimated noise component is subtracted from the primary audio signal to produce an output signal. During steady-state operation, the adaptive filter coefficients are updated as to minimize the difference between the primary audio signal and the estimated noise component. Steady-state operation is identified automatically by monitoring the power level of the primary or secondary audio signal, or the power level of the output signal. Coefficient updating is suspended when the monitored power level rises from a steady state to an unsteady state, and is resumed when the monitored power level returns to its previous steady-state level, or settles into a new steady state.

Central, auditory mechanisms of perceptual compensation for spectral-envelope distortion.

Abstract: The spectral envelope is a major determinant of the perceptual identity of many classes of sound including speech. When sounds are transmitted from the source to the listener, the spectral envelope is invariably and diversely distorted, by factors such as room reverberation. Perceptual compensation for spectral‐envelope distortion was investigated here. Carrier sounds were distorted by spectral envelope difference filters whose frequency response is the spectral envelope of one vowel minus the spectral envelope of another. The filter /i/ minus /q/ and its inverse were used. Subjects identified a test sound that followed the carrier. The test sound was drawn from an an /itch/ to /qtch/ continuum. Perceptual compensation produces a phoneme boundary difference between /i/ minus /q/ and its inverse. Carriers were the phrase ‘‘the next word is’’ spoken by the same (male) speaker as the test sounds, signal‐correlated noise derived from this phrase, the same phrase spoken by a female speaker, male and female versions played backwards, and a repeated end‐point vowel. The carrier and test were presented to the same ear, to different ears, and from different apparent directions (by varying interaural time delay). The results show that compensation is unlike peripheral phenomena, such as adaptation, and unlike phonetic perceptual phenomena. The evidence favors a central, auditory mechanism.

Recognition of Speech Produced in Noise

Abstract: A two-part study examined recognition of speech produced in quiet and in noise by normal hearing adults. In Part I 5 women produced 50 sentences consisting of an ambiguous carrier phrase followed by a unique target word. These sentences were spoken in three environments: quiet, wide band noise (WBN), and meaningful multi-talker babble (MMB). The WBN and MMB competitors were presented through insert earphones at 80 dB SPL. For each talker, the mean vocal level, long-term average speech spectra, and mean word duration were calculated for the 50 target words produced in each speaking environment. Compared to quiet, the vocal levels produced in WBN and MMB increased an average of 14.5 dB. The increase in vocal level was characterized by increased spectral energy in the high frequencies. Word duration also increased an average of 77 ms in WBN and MMB relative to the quiet condition. In Part II, the sentences produced by one of the 5 talkers were presented to 30 adults in the presence of multi-talker babble und...