摘要:

A set of rules is devised whereby the component types of the envelope of a house or an apartment may be chosen from a knowledge of their acoustical properties, their relative areas, the degree of intrusive sound that may be tolerated, and the noise exposure forecast contours.

ISSN:0001-4966    

DOI:10.1121/1.1913418

出版商:Acoustical Society of America    

年代:1973

数据来源: AIP

摘要:

When subjects are required to make a forced choice between pairs of pulses dichotic with respect to time (Δt) from pairs of pulses dichotic with respect to intensity (ΔI), the resultant data appear as V‐shaped functions relating discrimination accuracy to interaural time asymmetry (ΔI). The sharpness of the limbs (the spread of the functions), the appearance of a well‐defined minimum, the Δtat which the minimum point is found, and the accuracy of discrimination at the minimum point of the function depend upon the parameters of summed binaural sensation level, and the interaural intensity asymmetry. The interaural time asymmetry (Δt) associated with the minimum point of the function can be used as an index of the degree to which Δtcan be matched to ΔIwhen the parameters of ΔIand summed binaural sensation level are varied. The ratio of Δtassociated with the minimum of the function to ΔI, i.e., Δt/ΔIin microseconds/dB, is found to be inversely related to summed binaural sensation level.

ISSN:0001-4966    

DOI:10.1121/1.1913419

出版商:Acoustical Society of America    

年代:1973

数据来源: AIP

摘要:

Using previously developed theoretical results we show the relationship between cochlear models with both chambers fluid filled and those with tympanic chamber empty. Numerical solutions of the equations show significant quantitative differences, between the two cases, in both amplitude and place of the basilar membrane displacement patterns.

ISSN:0001-4966    

DOI:10.1121/1.1913420

出版商:Acoustical Society of America    

年代:1973

数据来源: AIP

摘要:

Masked thresholds were obtained for ten frequencies between 125 and 8000 Hz at three different noise levels on five subjects. Threshold procedure was 4IFC, in which duration of the tone was 300 msec. Values of bothS/N0andE/N0(whereSis power of tone at MT,Eis energy of tone at MT, andN0is spectrum level of the noise) were calculated from this set of data. The results of the present study were compared to those of Hawkins and Stevens (1950) and those of Green, McKey, and Licklider (1959). The problem of converting a signal‐to‐noise ratio measurement into an indirect estimate of critical bandwidth is discussed.

ISSN:0001-4966    

DOI:10.1121/1.1913421

出版商:Acoustical Society of America    

年代:1973

数据来源: AIP

摘要:

Performance in a simultaneous two‐frequency detection task was studied under monaural and dichotic conditions of signal presentation. In the basic task a 630‐Hz tone, a 1400‐Hz tone, neither tone, or both tones occurred with equal likelihood on an experimental trial. The observer had to specify which of these events had occured. Performance was examined: (a) when the signal could occur only in the right earphone channel, and (b) when the 630‐ and 1400‐Hz signals were confined, respectively, to the left and right earphone channels. Single‐frequency comparison conditions were also run. A performance decrement was observed in both of the two‐frequency conditions compared to the single‐frequency condition. However, there was no consistent difference between the monaural and dichotic two‐frequency conditions. An analysis of the conditional detection probabilities revealed the presence of a cross‐frequency interference effect on trials when a signal was present at the other frequency. This effect was sufficient to account for the differences between single‐frequency and two‐frequency detection performance.

ISSN:0001-4966    

DOI:10.1121/1.1913422

出版商:Acoustical Society of America    

年代:1973

数据来源: AIP

摘要:

Monaural loudness‐adaptation measurements were made at several suprathreshold levels for 500 and 4000 Hz with normal‐hearing subjects. A unique procedure used the subject as a null device and adaptively varied the signal level over time until no change in loudness was indicated. The results indicated no monaural loudness adaptation. These findings support similar data obtained by other investigators using delayed‐balance procedures. It was concluded that the adaptation effects observed in experiments using some form of simultaneous, binaural stimulation apparently are due to binaural interaction and may reflect central as well as peripheral influences.

ISSN:0001-4966    

DOI:10.1121/1.1913423

出版商:Acoustical Society of America    

年代:1973

数据来源: AIP

摘要:

It has been shown previously that a gradient microphone close to the lips is capable of providing an intelligible speech signal in spite of standing waves within a diving mask. It keeps most spectral levels close to their natural balance, but it does not compensate for detuning of the first formant by limited mask cavity volume. The present study is an investigation of a simulated diving mask and speech transmitter, whose distortion of speech is primarily by detuning of the vocal tract. It splits the first two formants into a triplet and de‐emphasizes the uppermost frequency of the triplet. The gradient microphone restores emphasis to the uppermost frequency and de‐emphasizes the middle frequency. This results in a formant structure similar to that of undistorted speech, with high intelligibility and most of the hollowness suppressed.

ISSN:0001-4966    

DOI:10.1121/1.1913424

出版商:Acoustical Society of America    

年代:1973

数据来源: AIP

摘要:

The high dynamic range and extremely high fringe contrast attainable by using double‐pulsed holographic interferometry enable one to analyze the performance of a loudspeaker by observing the fine details of the resulting vibration patterns.

ISSN:0001-4966    

DOI:10.1121/1.1913425

出版商:Acoustical Society of America    

年代:1973

数据来源: AIP

摘要:

When a source of discrete‐frequency sound is placed in a reverberation room, the sound‐power output depends on the source position and frequency. In addition, the measured sound‐pressure level depends on microphone position. In this paper, some experimental data are presented that are relevant to both the microphone path length required for an accurate determination of the space/time average mean‐square pressure in the room, and the variations of sound‐power output with source position in the room. Based on theoretical and experimental results, some guidelines are proposed for the determination of the sound‐power radiated by discrete‐frequency sources in a reverberation room.

ISSN:0001-4966    

DOI:10.1121/1.1913426

出版商:Acoustical Society of America    

年代:1973

数据来源: AIP

摘要:

Study of midsagittal x‐ray tracings reveals that the vocal‐tract outline can be accurately represented by means of variables specifying the positions of the jaw, tongue body, tongue tip, lips, velum, and hyoid. As the articulators move, they modify the vocal‐tract cross‐sectional area and the vocal‐tract transfer function computed thereform. The speech signal may be synthesized by concatenating the responses to repeated excitation of the quasistatic vocal tract. Vowels are specified in terms of variables denoting the positions of the jaw, tongue body, lips, and velum. Consonants are implemented as transformations on the underlying vowel‐derived articulatory states that satisfy given constraints on the position of an articulator relative to the fixed structures. The set of states which satisfy the given constraint corresponds to the allowed productions of the consonant. Coarticulation effects control the selection of the underlying state and thus determine the particular consonant produced. Vowel‐consonant‐vowel sequences generated with the aid of rules for articulator movement and the articulator‐position to vocal‐tract cross‐sectional‐area transformation are intelligible and exhibit coarticulation in agreement with acoustic measurements.

ISSN:0001-4966    

DOI:10.1121/1.1913427

出版商:Acoustical Society of America    

年代:1973

数据来源: AIP