Two Methods to Test Transducer Array Directivity

2014 ◽  
Vol 912-914 ◽  
pp. 1485-1488
Author(s):  
Hong Liu ◽  
Guo Zhu Zhao
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Beam Width ◽  
Directivity Pattern ◽  
Acute Angle ◽  
Pressure Level ◽  
The Other ◽  
Transducer Array ◽  
Acoustic Transducer ◽  
The One

An array which possess more array element number and whose frequency of the drive signal can be as large as possible in a range, directivity will be more preferable. On the other hand, when the structure of the sound radiating surface of the transducer or array layout is symmetrical, the corresponding directivity pattern will be symmetrical. In order to test transducer directivity, two methods are designed. The one is to measure the ultrasonic sound pressure level by instruments. The sound pressure level is measured at multiple points to deduce the directivity angle of the acoustic transducer array. The beam width of the 3×3 array is about at 23kHz, and the directivity acute angle is about 10°; higher frequencies will lead to the side lobes, but it can be negligible when compared to the main lobe. The other method is using the frequency analyzer to test transducer directivity in a silencer chamber. The sound pressure level can be read out from frequency response diagrams. The angle between the sound pressure value that decreasing 3db from the max value 111.7db and the max value is about 11°. So the directivity acute angle is about 11°. It should be noticed that, as the directivity diagram can not be directly attributed, there is some deviation in the conclusion.

Research on the High-Power Directional Acoustic Transducer

2014 ◽  
Vol 912-914 ◽  
pp. 753-756
Author(s):  
Guo Zhu Zhao ◽  
Li Xuan Ma
Keyword(s):  
Rare Earth ◽  
Sound Source ◽  
Beam Width ◽  
Directivity Pattern ◽  
Acute Angle ◽  
The Other ◽  
Acoustic Transducer ◽  
Element Number ◽  
The Individual ◽  
Selection Of

Through studying how to affect acoustic directivity with MATLAB software, it show that selection of a relatively larger surface of the transducer and a relatively closer transducer interval will be more preferable for directivity. While an array which possess more array element number and whose frequency of the drive signal can be as large as possible in a range, directivity will be more preferable. On the other hand, when the structure of the sound radiating surface of the transducer or array layout is symmetrical, the corresponding directivity pattern will be symmetrical. At a frequency of 10kHz, the individual rare earth magnetostrictive transducers its first point of the simulation carried out before the test. Sounding board with aluminum by the method used to improve the sound source diameter. With the sound plate diameter incrementing, the smaller the angle of the directivity. The beam width of the 3×3 array is about at 23kHz, and the directivity acute angle is about 10°, with a sounding board by the method used to improve their the diameter of the sound source, so as to realize the sound has directivity is feasible.

Widening Frequency Band of Uniform SPL Distribution Using Adaptive Genetic Algorithm

2013 ◽  
Vol 427-429 ◽  
pp. 1040-1043
Author(s):  
Zhao Xin Huang ◽  
Sai Ma ◽  
Hui Wang
Keyword(s):  
Genetic Algorithm ◽  
Objective Function ◽  
Uniform Distribution ◽  
Frequency Band ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Directivity Pattern ◽  
Pressure Level ◽  
Adaptive Genetic Algorithm ◽  
Genetic Operators

Uniform sound pressure level (SPL) distribution of linear phased loudspeaker array is limited by frequency. This paper widens the applicable frequency band of uniform SPL distribution in a linear listening area. By using an improved adaptive genetic algorithm (which contains a novel objective function, modified genetic operators and parameter setups) to control the directivity pattern details accurately, uniform distribution of SPL on a linear listening line in a wider frequency is achieved. The simulation and experimental results show that the SPLs on the test listening line are basically uniform from 200Hz to 500Hz, which demonstrates that the improvement of adaptive genetic algorithm is effective.

scholarly journals Determination of thermal and acoustic comfort inside a vehicle’s cabin

2018 ◽  
Vol 32 ◽  
pp. 01002
Author(s):  
Alexandra Ene ◽  
Tiberiu Catalina ◽  
Andreea Vartires
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Pressure Level ◽  
The Other ◽  
Air Velocity ◽  
Acoustic Comfort ◽  
Comfort Parameters

Thermal and acoustic comfort, inside a vehicle’s cabin, are highly interconnected and can greatly influence the health of the passengers. On one hand, the H.V.A.C. system brings the interior air parameters to a comfortable value while on the other hand, it is the main source of noise. It is an intriguing task to find a balance between the two. In this paper, several types of air diffusers were used in order to optimize the ratio between thermal and acoustic interior comfort. Using complex measurements of noise and thermal comfort parameters we have determined for each type of air diffuser the sound pressure level and its impact on air temperature and air velocity.

A Criterion for Predicting the Annoyance Due to Lower Level Low Frequency Noise

1983 ◽  
Vol 2 (4) ◽  
pp. 160-168 ◽  
Author(s):  
N. Broner ◽  
H.G. Leventhall
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Low Frequency ◽  
Threshold Effect ◽  
Pressure Level ◽  
The Other ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Estimation Task ◽  
Noise Annoyance

In a study of the annoyance due to low frequency noise, 75 subjects (consisting of 21 complainants and 54 controls) carried out a magnitude estimation task and rated the annoyance due to lower-level low frequency noise (55dB–75dB). After allowing for a threshold effect, it was found that the E-weighted sound pressure level was, in general, the best predictor of lower-level low frequency noise annoyance. However, it was not a significantly better predictor than any of the other nine noise measures considered. The widely available dB(A) noise measure was therefore suggested as a useful predictor of group annoyance due to lower-level low frequency noise.

Experimental Visualization of Sound Pressure Level and Vibration Around a Soundproof Barrier

2011 ◽  
Author(s):  
Fumio Shimizu ◽  
Kazuhiro Tanaka ◽  
Koji Yamamoto ◽  
Hiroshi Shigefuji
Keyword(s):  
Noise Reduction ◽  
Sound Pressure Level ◽  
Sound Source ◽  
Sound Pressure ◽  
Pressure Level ◽  
Heat Radiation ◽  
Sound Insulation ◽  
Vibration Displacement ◽  
The One ◽  
The Relationship

The noise and vibration control are the one of important issues. A soundproof barrier, which covers a sound source with sound absorbing materials, is very useful for the noise reduction. When large noise and high temperature heat emit from the sound source, we must also consider the heat radiation as well as the noise reduction. The purpose of the present study is to investigate the relationship between sound pressure level and vibration on a soundproof barrier around a sound source. The effect of heat radiation hole on the sound insulation performance of the soundproof barrier is also investigated. The sound pressure level and the vibration displacement were similarly distributed on the surface of the barrier. Therefore, the vibration of the barrier was strongly influenced to the sound pressure level of the transmitted sound.

Contributions of Voice and Nonverbal Communication to Perceived Masculinity–Femininity for Cisgender and Transgender Communicators

2020 ◽  
Vol 63 (4) ◽  
pp. 931-947
Author(s):  
Teresa L. D. Hardy ◽  
Carol A. Boliek ◽  
Daniel Aalto ◽  
Justin Lewicke ◽  
Kristopher Wells ◽  
...  
Keyword(s):  
Fundamental Frequency ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Vocal Tract ◽  
Presentation Mode ◽  
Pressure Level ◽  
Presentation Modes ◽  
Audiovisual Stimuli ◽  
Vocal Tract Resonance ◽  
Point Light

Purpose The purpose of this study was twofold: (a) to identify a set of communication-based predictors (including both acoustic and gestural variables) of masculinity–femininity ratings and (b) to explore differences in ratings between audio and audiovisual presentation modes for transgender and cisgender communicators. Method The voices and gestures of a group of cisgender men and women ( n = 10 of each) and transgender women ( n = 20) communicators were recorded while they recounted the story of a cartoon using acoustic and motion capture recording systems. A total of 17 acoustic and gestural variables were measured from these recordings. A group of observers ( n = 20) rated each communicator's masculinity–femininity based on 30- to 45-s samples of the cartoon description presented in three modes: audio, visual, and audio visual. Visual and audiovisual stimuli contained point light displays standardized for size. Ratings were made using a direct magnitude estimation scale without modulus. Communication-based predictors of masculinity–femininity ratings were identified using multiple regression, and analysis of variance was used to determine the effect of presentation mode on perceptual ratings. Results Fundamental frequency, average vowel formant, and sound pressure level were identified as significant predictors of masculinity–femininity ratings for these communicators. Communicators were rated significantly more feminine in the audio than the audiovisual mode and unreliably in the visual-only mode. Conclusions Both study purposes were met. Results support continued emphasis on fundamental frequency and vocal tract resonance in voice and communication modification training with transgender individuals and provide evidence for the potential benefit of modifying sound pressure level, especially when a masculine presentation is desired.

Case study: Theoretical calculation model and variable condition analysis research on the water-splashing noise for natural draft wet cooling towers

2020 ◽  
Vol 68 (2) ◽  
pp. 137-145
Author(s):  
Yang Zhouo ◽  
Ming Gao ◽  
Suoying He ◽  
Yuetao Shi ◽  
Fengzhong Sun
Keyword(s):  
Theoretical Model ◽  
Sound Pressure Level ◽  
Water Droplet ◽  
Water Distribution ◽  
Sound Pressure ◽  
Cooling Tower ◽  
Distribution Patterns ◽  
Calculation Model ◽  
Pressure Level ◽  
Cooling Towers

Based on the basic theory of water droplets impact noise, the generation mechanism and calculation model of the water-splashing noise for natural draft wet cooling towers were established in this study, and then by means of the custom software, the water-splashing noise was studied under different water droplet diameters and water-spraying densities as well as partition water distribution patterns conditions. Comparedwith the water-splashing noise of the field test, the average difference of the theoretical and the measured value is 0.82 dB, which validates the accuracy of the established theoretical model. The results based on theoretical model showed that, when the water droplet diameters are smaller in cooling tower, the attenuation of total sound pressure level of the water-splashing noise is greater. From 0 m to 8 m away from the cooling tower, the sound pressure level of the watersplashing noise of 3 mm and 6 mm water droplets decreases by 8.20 dB and 4.36 dB, respectively. Additionally, when the water-spraying density becomes twice of the designed value, the sound pressure level of water-splashing noise all increases by 3.01 dB for the cooling towers of 300 MW, 600 MW and 1000 MW units. Finally, under the partition water distribution patterns, the change of the sound pressure level is small. For the R s/2 and Rs/3 partition radius (Rs is the radius of water-spraying area), when the water-spraying density ratio between the outer and inner zone increases from 1 to 3, the sound pressure level of water-splashing noise increases by 0.7 dB and 0.3 dB, respectively.

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