SOURCE 28 · MATERIALS · 15 / 17
Acoustic Materials, Dampers & Mesh
A source-aligned rewrite of acoustic materials for IEMs: flow resistance, porous damping, nozzle mesh, adhesives, shell stability and production variation.
28.1 Nozzle mesh and airflow resistance
Nozzle mesh protects from debris but also adds resistance. Weave, thickness, coating and adhesive boundary can shift treble, so it must be specified and controlled.
28.2 Porous damping and acoustic absorption
Porous materials dissipate energy and can tame bore resonances. Their resistance must remain stable across humidity, ageing and assembly.
28.3 Porosity, stiffness and transmission loss
Metal, resin and plastic do not have a single sound. Wall stiffness, cavity dimensions, internal finish and tolerance control shape the result more directly.
28.4 Shell material and tolerance control
Glue near a vent, uneven mesh seating or a blocked bore can create unit variation. Drawings must specify part, location and inspection.
28.5 Ageing and production validation
Sweat, wax, moisture, temperature cycles and repeated tip changes can alter resistive parts. Reliability testing protects long-term tuning.
28.6 Acoustic-material system summary
Flow resistivity, porosity, stiffness and transmission loss determine how a material behaves. A mesh or porous damper must be tested as a production part, not described only by appearance.