气流扬声器全调制发声方法研究

发展了一种耗气量小和背景噪声低的气流声源新调制模型。建立了全调制气流声源模型,零流量被设置为气流扬声器的静态,音频调制信号经过了去下包络预处理。控制通气量与调制信号成正比,降低气流消耗和减小背景噪声,与四类主要气流扬声器调制方式的效率进行了对比。与半通气调制方法相比较,全调制方法对典型语言广播的气流利用率从5%提高到51.5%,播放正弦波的气流利用率始终保持最大值60%,并使播放声音的信噪比提高15 dB以上。 

A full modulated way for pneumatic loudspeaker sound generation

A method of flow modulation was developed for large power pneumatic loudspeaker to reduce gas consump-tion and background noise. A modulation method of the flow control is provided to perform advanced sound performance and high effectiveness with large gas-sound ratio. First, a full modulation is studied in a model to find its principle of sound generation by gas from horn throat. According to this model, modulator of pneumatic loudspeaker is adjusted in none-flow when in static state, sound wave is pre-processed to cut its lower envelope to form a new signal to control the gas-flow. This flow is proportional to sound's amplitude. The sound's property is much better than before with less gas wasting. Four different typical modulation models are discussed in comparing their effectiveness. For a typical male's speech signal, comparing with half-flow modulation, gas utilization ratio of this full modulation is enhanced from 5% to 51.5%, for a sinusoidal wave sound, the ratio keep in a maximum 60% in different modulation-rate , SNR of the sound generating is enhanced over 15 dB.