手机音腔及出音孔的设计计算.ppt

,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,Optimal Sound Matching Solution,through Helmholtz,resonator theory,Basic theory,Helmholtz Resonator was invented for sound analysis by H.VON Helmholtz(18211894),Its applications are various from bell,violin,guitar and bass speaker cabinet.,It features shorter neck and volume bottle than wave as shown below.,Specific frequency depends on air volume in neck(weight)and volume in the bottle(spring),So specific frequency is calculated as,below.,a,:Necks area(),V,:Resonator volume(,),L,:Necks length(,m,),C,:Sound velocity(344m/s),Therefore any shapes of resonator is not affecting Resonant Frequency.,If the volume&necks length is same,the resonator has same resonant frequency even in different shape.,Basic principle,Optimal Sound Matching Solution through Helmholtz,resonator theory,Ex.1),Whats the resonant frequency in case of a bottle with outer dia.9.8cm,neck length10cm,neck outer dia.3cm?,Example,Optimal Sound Matching Solution through Helmholtz,resonator theory,a :1.,a:Air Hole,-Ze :8 ohm,Back Volume,Back volume:2.,Back volume:2.,SS1534P-008 GRAPH in BAFFLE,We come to conclusion through proved theory as follows:,A:Frequency Response,Magn dB re 20.,Front Volume variation,Then SPL and sound quality is depending on how the resonant frequency is met with.,through Helmholtz resonator theory,4,269Hz 3,900Hz,a :1.,V:Front Volume,V:Front Volume,C :344 m/s(RT 20),92dB ZA:Live Curve TSR fund.,2.Application,(1)Inside structure of handset,a :,Hole total area(m,2),Speaker,L,CASE,V:Front Volume,a:Air Hole,Back Volume,L :,Case thickness(m),V :,Front volume(m,3),C :,344 m/s(RT 20),Application,Optimal Sound Matching Solution through Helmholtz,resonator theory,(2)Example model:SS1534P-008,-SIZE:15mm X 3.4 H,-Fo :850 Hz,-Ze :8 ohm,(3)Test conditions,*Input power:0.1W at 5cm,Basic principle,Optimal Sound Matching Solution through Helmholtz,resonator theory,B,K,Mode:TSR,A:Frequency Response,Magn dB re 20.00,Pa/V,100,200,500,1k,2k,5k,10k,Hz,60,70,80,90,100,110,dB,X:900.00Hz Y:98.92dB ZA:Live Curve TSR fund.,SS1534P-008 GRAPH in BAFFLE,Original test result,Optimal Sound Matching Solution through Helmholtz,resonator theory,(4)TEST according to some variations,Basic Structure,Air Hole quantity variation,Case thickness variation,Front Volume variation,Back Volume variation,Test condition,Optimal Sound Matching Solution through Helmholtz,resonator theory,Basic structure,a :1.55mm X 4 ea,C :344 m/s(RT 20),Back volume:2.42cc,=3,486Hz,Basic structure,Hand Set Matching Solution with Helmholtz,resonator,Speaker,L,CASE,V:Front Volume,a:Air Hole,Back Volume,-Fo :850 Hz,Basic structure,-SIZE:15mm X 3.,C :Sound velocity(344m/s),Case thickness variation,Air Hole quantity variation,Test result by front volume variation,Test result by front volume variation,Optimal Sound Matching Solution through Helmholtz resonator theory,2,465Hz 2,400Hz,C :Sound velocity(344m/s),Optimal Sound Matching Solution through Helmholtz resonator theory,47dB ZA:Live Curve TSR fund.,SS1534P-008 GRAPH in BAFFLE,3000kHz Y:96.,Basic theory,X:3.0000kHz Y:104.23dB ZA:Live Curve TSR fund.,B,K,Mode:TSR,Pa/V,100,200,500,1k,2k,5k,10k,Hz,60,70,80,90,100,110,dB,3,486Hz,3,000Hz,Test result,Optimal Sound Matching Solution through Helmholtz,resonator theory,Air Hole quantity variation,a :1.55mm X 4 ea,1.55mm X 2 ea,C :344 m/s(RT 20),Back volume:2.42cc,=2,465Hz,Air hole variation,Optimal Sound Matching Solution through Helmholtz,resonator theory,Speaker,L,CASE,V:Front Volume,a:Air Hole,Back Volume,B,K,Mode:TSR,A:Frequency Response,Magn dB re 20.00,Pa/V,100,200,500,1k,2k,5k,10k,Hz,60,70,80,90,100,110,dB,X:2.4000kHz Y:101.47dB ZA:Live Curve TSR fund.,2,465Hz,2,400Hz,Test result of air hole changed,Hand Set Matching Solution with Helmholtz,resonator,Case thickness variation,a :1.55mm X 4 ea,L:1.55mm,C :344 m/s(RT 20),=2,745Hz,Case thickness changed,Optimal Sound Matching Solution through Helmholtz,resonator theory,Speaker,L,CASE,V:Front Volume,a:Air Hole,Back Volume,B,K,Mode:TSR,A:Frequency Response,Magn dB re 20.00,Pa/V,100,200,500,1k,2k,5k,10k,Hz,60,70,80,90,100,110,dB,X:2.6000kHz Y:102.29dB ZA:Live Curve TSR fund.,2,745Hz,2,600Hz,Test result by case thickness variation,Optimal Sound Matching Solution through Helmholtz,resonator theory,Front Volume variation,a :1.55mm X 4 ea,V :1.2cc,C :344 m/s(RT 20),Back volume:2.42cc,=4,269Hz,Front volume variation,Optimal Sound Matching Solution through Helmholtz,resonator,theory,Speaker,L,CASE,V:Front Volume,a:Air Hole,Back Volume,B,K,Mode:TSR,A:Frequency Response,Magn dB re 20.00,Pa/V,100,200,500,1k,2k,5k,10k,Hz,60,70,80,90,100,110,dB,X:3.9000kHz Y:105.25dB ZA:Live Curve TSR fund.,4,269Hz,3,900Hz,Test result by front volume variation,Optimal Sound Matching Solution through Helmholtz,resonator theory,Back Volume variation,a :1.55mm X 4 ea,C :344 m/s(RT 20),Back volume:2.42cc,Back volume variation,Optimal Sound Matching Solution through Helmholtz,resonator theory,Speaker,L,CASE,V:Front Volume,a:Air Hole,Back Volume,B,K,Mode:TSR,Pa/V,100,200,500,1k,2k,5k,10k,Hz,60,70,80,90,100,110,dB,X:1.3000kHz Y:96.65dB ZA:Live Curve TSR fund.,Loss of,low sound,Test result by back volume changed,Optimal Sound Matching Solution through Helmholtz,resonator theory,3.Conclusion,We come to conclusion through proved theory as follows:,1)The quantity of front air hole,Resonant Frequency,2)Front case thickness ,Resonant Frequency,3)Front volume,Resonant Frequency,4)Back volume,Low sound,Optimal acoustic solution in handset design can be coming from,Helmholtz,resonator theory.,In case that speaker itself has flat frequency response,specific resonant frequency is generating when being mounted in the handset.Then SPL and sound quality is depending on how the resonant frequency is met with.,In conclusion the optimal resonant frequency should be set between 2KHz and 5KHz because these area is most sensitive one for human ear.,Analysis&Conclusion,Optimal Sound Matching Solution through Helmholtz,resonator theory,HANDSET Design considerations for Optimal Sound Matching,1.The bigger back volume in speaker,the rich sound at low frequency.,2.Sound leakage at front cover is causing decreasing sound at low frequency.,3.The bigger sound hole in handset,the clearer sound.,4.Should be designed for no interference in between front and back bouncing sound from the speaker,Handset design application,Optimal Sound Matching Solution through Helmholtz,resonator theory,Handset design application,Optimal Sound Matching Solution through Helmholtz,resonator theory,谢谢观看,