1、Insert Headset SimulationCain GuIn Brief This simulation is based on Electro-Mechanical-Acoustic Analogies theory, while the tubes are treated as transfer line. The acoustics damping of tube inner surface is not considered and all the meshes treated as Resistance. The simulation result is corrected
2、by test result, just to show the trends and for reference.Back volume 1CAB1 Back volume 2CAB2Rear MeshRABFront Volume 2CAF2Front Volume 1CAF1TubeLAT+CATFront MeshRAFIEC711 Artificial Ear with Ear CanalRubber CavityCARCanal CavityCAC1. The volume in front of diaphragm should be considered.2. The acou
3、stic elements of the real like CAB1, RAB and CAB2 can be treated as dump elements, others like Front Volume, Tube and Cavities cant be treated as dump block.Data of WH205 Back volume 1: 0.4ccm Back volume 2: 0.05ccm Front volume 1: 0.015ccm Front volume 2: 0.045ccm Tube: 3.1mmX3.7mm Rubber Cavity: 5
4、.6mmX4.9mm(Rough) Canal Cavity: 7.5mmX4mm(Rough) f0 of driver: 665HzSimulation CiruitOriginal SettingBack Volume 1 ChangesBack volume 1 changes from 0.8ccm to 0.2ccmRear Mesh ChangesRear Mesh changes from thin to thick.This also affect the peak around 3kHzBack Volume 2 ChangesActually this volume is
5、 inside the driver, combine together with Mms to define fs of driver. Drivers RMS ChangesThe Rms only affects the peak around 3kHz(fs).Front Mesh ChangesChange the Front Mesh from thin to thick.The Mesh can damp all the peaks.Front Volume ChangesHere Front Volume = Front Volume 1 + Front Volume 2Fro
6、nt Volume changes from 40mm3, 85mm3 and 100mm3Tube Diameter ChangesThe Tube inner Diameter changes from 2mm to 3.1mm and 4.5mm.Tube Length ChangesThe Tube Length change from 3.7mm to 4.5mm and 5.3mm.Rubber Cavity Length ChangeRubber Cavity length changes from 5mm to 6mm and 7mm.Ear Canal Length Chan
7、gesEar Canal Length changes from 2mm to 4mm and 6mm, that depends on how deep the headphone insert into ear canal, ergonomics related.Compare to the ear rubber and tube length change, this length affect the SPL around 8k-9kHz much.Simulation result of diff. conditions WH205 HP5 B3.0 Small Tube Origi
8、nal Small Tube and Small Front Volume Improvement (Smaller Front Volume)WH205 and HP5 are in same level, the difference in 3kHz due to the drivers mechanical damping Rms and difference in 9kHz.Small diameter tube cant be used due to SPL drops much at high freq. range. Make front volume smaller can g
9、et improvement.Back volume 1CAB1 Back volume 2CAB2Rear MeshRABFront Volume 2CAF2Front Volume 1CAF1TubeLAT+CATFront MeshRAFIEC711 Artificial Ear with Ear CanalRubber CavityCARCanal CavityCACMake Front Volume 1 much smaller like a tube Simulation result with Front Mesh WH205 HP5 B3.0 Improvement (Smal
10、ler Front Volume)Small Tube and small Front Volume can achieve the peak around 6kHz, the behavior of front mesh is different, while this is in controlled and acceptable level.1. The volume in front of diaphragm should be considered.2. The acoustic elements of the real like CAB1, RAB and CAB2 can be treated as dump Back volume 1CAB1Back volume 2CAB2Rear MeshRABVent HoleLAV+CAVFront VolumeCAFFront GrillLAG+CAGFront Mesh under GrillRAFCanal and part of Concha CavityCACLeakageLAL+CAL
