scholarly journals Even Dispersion Design for a Compact Linear Loudspeaker Array with Adaptive Genetic Algorithm

2019 ◽  
Vol 10 (1) ◽  
pp. 227
Author(s):  
Juanjuan Cai ◽  
Yongqiang Pang ◽  
Hui Wang ◽  
Yutian Wang
Keyword(s):  
Genetic Algorithm ◽  
Frequency Band ◽  
Filter Bank ◽  
Sound Pressure ◽  
Pressure Level ◽  
Parameters Optimization ◽  
Adaptive Genetic Algorithm ◽  
Linear Phase ◽  
Radiation Characteristics ◽  
Sound Reinforcement

Even dispersion is important for live sound reinforcement systems; however, it needs to be carefully designed when using a linear loudspeaker array. This is because the audience area is often large, while the loudspeakers are placed centrally in this case for convenience, and thus both the level and the frequency balance may not remain reasonably constant for all audiences. To solve this problem, the adaptive genetic algorithm is firstly introduced in the parameters optimization. Secondly, taking the radiation characteristics at different frequencies into account, a linear-phase non-uniform filter bank is proposed to decompose the broad frequency band into several sub-bands. The audio is re-synthesized with the optimized parameters in each frequency band for a linear loudspeaker array. To show the validity of the proposed method, the simulations and the experiments are conducted to demonstrate that the sound pressure level in the audience area is distributed within ± 1.33 dB, ranging from 200 Hz to 4000 Hz.

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 Effects of pipe casing structure on acoustic emission characteristics of underwater pyrotechnic combustion

2019 ◽  
Vol 39 (1) ◽  
pp. 149-157
Author(s):  
Jie Li ◽  
Jun Du ◽  
Xian Chen ◽  
Yanli Wang
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Acoustic Radiation ◽  
Structural Characteristics ◽  
Bubble Formation ◽  
Pressure Level ◽  
Radiation Characteristics ◽  
Acoustic Testing ◽  
Gas Volume ◽  
Broadband Sound

In order to investigate the acoustic radiation characteristics of underwater, a pipe casing was introduced and the effects of its main structural characteristics on underwater combustion acoustic radiation were studied by acoustic testing. The results show that the addition of the pipe casing significantly increased the sound pressure level of underwater pyrotechnic combustion, especially the peak of sound pressure level that was increased by 15.9 dB from 155.5 to 171.4 dB at the frequency of 125 and 100 Hz. But the addition of the pipe casing had little effect on the frequency. These results indicated that adding a pipe casing is effective for improving sound pressure level in underwater pyrotechnic combustion. An increase in nozzle diameter from 10 to 12.5 mm resulted in an increase of gas volume, so the peak of sound pressure level and broadband sound pressure level is higher. Changing the pipe casing direction to vertical downward will make the bubble formation period shorter, which will generate more bubbles and strong wake; the interaction between bubbles and wake results in a higher intensity of turbulence, which accounts for the coalescence and breakup of bubbles in the fluid. Besides, changing the diameter of pipe casing can be used to lower the frequency of underwater noise.

Adaptive Genetic Algorithm Based Parameters Optimization of PI Controller for Battery System in Wind Farm

2014 ◽  
Vol 1055 ◽  
pp. 375-382
Author(s):  
Hui Ren ◽  
Dan Wei ◽  
David Watts ◽  
Jia Qi Fan
Keyword(s):  
Genetic Algorithm ◽  
Wind Farm ◽  
Storage System ◽  
Pi Controller ◽  
Parameters Optimization ◽  
Adaptive Genetic Algorithm ◽  
Trial And Error ◽  
Battery System ◽  
Trial And Error Method ◽  
Error Method

The randomness and intermittence of wind farm real power generation bring challenges to power system operation, and installing battery system for the mitigation of the fluctuation of wind farm output, following the short-term forecasting curve, even adjusting the output according to the operator’s requirement is a possible way to address the problem from the wind farm side. After a review of various storage control strategies for stabilizing the fluctuation of wind power output, the model of battery energy storage system as well as its control strategy is introduced. Adaptive Genetic Algorithm (AGA) is used for the optimization of PI control parameters. Simulation shows the effectiveness of the proposed method. Moreover, comparing with the trial-and-error method, the optimization algorithm proposed has the advantage of finding the optimal parameters under the lack of experience on PID control, and combined with trial-and-error method, the difficulties engineer could face on tuning the parameters of PI controller is decreased, which increases the feasibility for parameters of PI controller’s being transplanted to similar applications.

Application of Hartmann Acoustic Generator in Source of Underwater Pyrotechnic Combustion

2013 ◽  
Vol 787 ◽  
pp. 638-643
Author(s):  
Jie Li ◽  
Hua Guan ◽  
Dong Ming Song ◽  
Qi Wang ◽  
Jun Du ◽  
...  
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Acoustic Radiation ◽  
Structural Parameters ◽  
Resonant Cavity ◽  
Experimental Studies ◽  
Combustion Products ◽  
Pressure Level ◽  
Radiation Characteristics ◽  
Acoustic Frequency

In order to investigate acoustic radiation characteristics of underwater pyrotechnic combustion, Hartmann acoustic generator was applied and its main structural parameters effecting acoustic radiation characteristics were studied by using underwater acoustic measurement system. Experimental studies have shown that, when Hartmann acoustic generator was applied, the sound pressure level of underwater pyrotechnic combustion increased significantly because of the strengthening of turbulence degree. The distance between the nozzle and the resonant cavity is an important factor of affecting acoustic radiation characteristics of Hartmann acoustic generator. When the resonant cavity was placed in the unstable pressure area, it could stimulate strong sound waves. On account of the resistance of the water, the combustion products speed of reaching resonant cavity drooped and the collision strength between the feedback combustion products and the newly generated products reduced. So when the distance was larger, the SPL(sound pressure level) was smaller. The SPL of underwater pyrotechnic combustion increased and the acoustic frequency moved to the low frequency with the depth of resonant cavity increased, which is consistent with the acoustic characteristics of Hartmann acoustic generator applied in air.

Multichannel loudness compensation method based on segmented sound pressure level for digital hearing aids

2017 ◽  
Vol 31 (19-21) ◽  
pp. 1740059 ◽  
Author(s):  
Ruiyu Liang ◽  
Ji Xi ◽  
Yongqiang Bao
Keyword(s):  
Sound Pressure Level ◽  
Hearing Aids ◽  
Filter Bank ◽  
Sound Pressure ◽  
Pressure Level ◽  
Hearing Impaired ◽  
Compensation Method ◽  
Digital Hearing Aids ◽  
Gain Compensation ◽  
Adjacent Channels

To improve the performance of gain compensation based on three-segment sound pressure level (SPL) in hearing aids, an improved multichannel loudness compensation method based on eight-segment SPL was proposed. Firstly, the uniform cosine modulated filter bank was designed. Then, the adjacent channels which have low or gradual slopes were adaptively merged to obtain the corresponding non-uniform cosine modulated filter according to the audiogram of hearing impaired persons. Secondly, the input speech was decomposed into sub-band signals and the SPL of every sub-band signal was computed. Meanwhile, the audible SPL range from 0 dB SPL to 120 dB SPL was equally divided into eight segments. Based on these segments, a different prescription formula was designed to compute more detailed gain to compensate according to the audiogram and the computed SPL. Finally, the enhanced signal was synthesized. Objective experiments showed the decomposed signals after cosine modulated filter bank have little distortion. Objective experiments showed that the hearing aids speech perception index (HASPI) and hearing aids speech quality index (HASQI) increased 0.083 and 0.082 on average, respectively. Subjective experiments showed the proposed algorithm can effectively improve the speech recognition of six hearing impaired persons.

Simulation of PID Control of Belt Conveyor System in Coal Mine by an Improved Adaptive Genetic Algorithm

2014 ◽  
Vol 614 ◽  
pp. 215-218 ◽  
Author(s):  
Lei Yu ◽  
Xu Long Zhang ◽  
Feng Wang
Keyword(s):  
Genetic Algorithm ◽  
Coal Mine ◽  
Pid Control ◽  
Pid Controller ◽  
Parameters Optimization ◽  
Step Response ◽  
Adaptive Genetic Algorithm ◽  
Belt Conveyor ◽  
Conveyor System ◽  
And Performance

In order to improve the problem of premature and performance of optimization, an improved adaptive genetic algorithm is proposed for parameters optimization of coal mine belt conveyor PID controller by applying the number of iterations to the crossover operation and mutation operation of genetic algorithm. The simulation shows that the step response of the improved algorithm is superior to the traditional adaptive genetic algorithm.

Experimental investigation on noise radiation characteristics of pulse detonation turbine engine

2016 ◽  
Vol 231 (2) ◽  
pp. 254-264
Author(s):  
Xiqiao Huang ◽  
Zhuo Guo ◽  
Kai Liu ◽  
Moqi Li ◽  
Longxi Zheng
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Single Pulse ◽  
Pressure Level ◽  
Radiation Characteristics ◽  
Two Phase ◽  
Turbine Engine ◽  
Noise Radiation ◽  
Pulse Detonation ◽  
Radial Turbine

The noise radiation characteristics of two-phase pulse detonation combustor and pulse detonation turbine engine were investigated under different operating frequencies utilizing gasoline as fuel and air as oxidizer. The sound pressure data of noise radiation were presented for both single-pulse detonation combustor tube and pulse detonation turbine engine. The experimental results implied that the peak sound pressure level of PDTE exit with inner diameter being 60 mm was about 157 dB under the operating frequencies which varied from 5 Hz to 25 Hz, while the peak sound pressure level of single-pulse detonation combustor tube exit was about 170 dB under the same condition. The far-field jet-noise measurements of the pulse detonation turbine engine showed that radial turbine interacting with the pulse detonation combustor could decrease the peak sound pressure level of pulse detonation combustor with the maximum acoustic attenuation being approximately 14.2 dB for the current test conditions, which could be contributed to the energy extraction by the radial turbine from the pulse detonation combustor exhaust flow. The sound pressure level of both pulse detonation combustor and pulse detonation turbine engine exit was function of directivity angle from the exhaust centerline. In all the experiments, the equivalence ratio of gasoline/air mixture and the fill fraction were 1.2 and 1.0, respectively.

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