1. 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
2. Silencers and mufflers
- absorption muffler
- effectiveness (frequency response, limiting effect, …)
- approximate solution of Piening
- reflection muffler
- insertion loss at an abrupt change of cross section
- insertion loss of a chamber
- resonance muffler
3. 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
