线列阵技术详解课件.ppt

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1、LineArrayTheoryThe“ideal”SoundSource.“理想化”的声源.OneuniqueSoundSource.点声源理论Nodestructiveinterferencebetweendifferentsoundsourcesreproducingthesamefreqrange.相同的声音频段内不同的声源之间不会产生声干涉现象.Soundsourcevibratesinphaseoveritswholesurface(Coherentwavesound).平面波理论令声音不存在相位差异.Nodistortionduetocr

2、ossovernetworkeffects.在分频网络中不容易产生失真.LineArrayTheoryThe“ideal”SoundSource“理想化”的声源.HorizontalCoveragewideenoughwithoneuniquesoundsource.Levelcontroloverdifferentaudienceareas.Morelevelforlongdistanceareas.Lesslevelforshortdistanceareas.Theseleveldifferencesleadtoauniformsoundfiel

3、d.LineArrayTheory唯一的点声源有足够宽的水平覆盖角度.不同的听音区域电平控制得更平均.远距离高电平控制听音区域.近距离低电平控制听音区域.这样令整个听音区域更平衡.IdealRibbonShapedSoundSource.Reproducesallaudiblefrequencyrange.About90ºofHorizontalcoverage.NarrowVerticalcoveragethatfitstotheaudienceareaneeds.Differentlevelsontopandbottom.LineArrayThe

4、ory重放所有频段真实的声音.约90º的水平覆盖角度.极窄的垂直覆盖角度能更有效地控制听音区域范围.在顶端和底端控制不同的发声电平.象这样的声源就可以获得圆柱体状的发生状况.理想化的带状发声声源.IdealRibbonShapedSoundSource.Fromasoundsourceassuch,aCylindricalwavewouldbeobtainedinsteadofthetypicalSphericalwaveproducedbyaconventionalcabinet.象这样的带状声源就可以生成柱面波，足以甚至超越传统结构的扬声器系统发

5、出的球面波LineArrayTheory理想化的带状发声声源.SphericalWave.SphereSurface=2pr2(2p(2r)2)/(2pr2)=4Eachdoublingofdistance,energyspreadsin4timesthepreviousSurface.20log4=6dBThismeansthateachdoublingofdistance,soundpressurelossis6dB.LineArrayTheory球体表面积=2pr2(2p(2r)2)/(2pr2)=4每增加一倍距离,能量将散播到相当于之前的4倍

6、球面积.20log4=6dB这就意味着每增加一倍距离，声压就会衰减6dB.球面波.CylindricalWave.LineArrayTheoryCilinderSurface=2prL(2p2rL/2prL)=2Eachdoublingofdistance,energyspreadsin2timesthepreviousSurface.20log2=3dBThismeansthateachdoublingofdistance,soundpressurelossis3dB.圆柱体表面积=2prL(2p2rL/2prL)=2每增加一倍距离,能量将散播到相

7、当于之前的2倍球面积.20log2=3dB这就意味着每增加一倍距离，声压只会衰减3dB.柱面波.LineArrayTheoryLineArrayTheoryisanintenttoapproachtotheidealsoundsourcebytheuseoftraditionalspeakersandcompressiondrivers.Howtoapproachtothisidealsystem?线性阵列理论完全可以使用传统的扬声器单元及压缩驱动器去实现这种理想的声源。如何去实现这种理想的系统呢?LineArrayTheoryToapproxima

8、teanarrayofconventionalindividualsoundsourcestoanideal