Sound absorber

• porous absorbers (mineral wool, melamine foams, hollow metal sphere structures, open-porous asphalts, fills, etc.)
  • characteristic values of materials (measuring method, airflow resistivity, porosity, tortuosity, …)
  • acoustic design of sound absorbers right at the wall as well as at a distance to the wall
  • covers of absorbers (perforated plates, …)
  • acoustic design of sound absorbing curtains
• micro-perforated sound absorbers
• plate-shaped oscillators and perforated plate-shaped oscillators
• Helmholtz resonators
• resonator with dimension equal to fourth of wave length
• combined absorbers

Silencers and mufflers

• absorption muffler
  • types of construction
  • effectiveness (frequency response, limiting effect, …)
  • fields of application
  • approximate solution of Piening
  • flow noise
  • pressure drop
  • exact solution
• reflection muffler
  • types of construction
  • effectiveness
  • fields of application
  • insertion loss at an abrupt change of cross section
  • insertion loss of a chamber
• resonance muffler
  • types of construction
  • effectiveness
  • fields of application

Computational design of silencers and mufflers and evaluation by means of acoustic measurements

• design of sound absorbers with analysis software
• acoustic evaluation of porous materials by measurement of airflow resistance with airflow resistivity meter AcoustiFlow^®
• acoustic design of silencers and mufflers by means of silencer software AcoustiCalc^®
• measurement of spectral transmission loss of silencers and mufflers in the test setup for mufflers AcoustiTube^® HighTemp