Predicts the sound absorption coefficients of porous materials such as fiberglass, mineral wool and polyester
Predicts both normal and random incidence absorption
Simple input of physical parameters
Predicts performance of perforated, slatted and panel absorbers
Estimates both the random incidence and normal incidence absorption coefficients as well as acoustic impedance
Up to two layers of different materials per absorber
Implemented Absorber Models
Zorba implemented the following Absorber Models:
Allard & Champoux
Delay + Bazley
Dunn + Davey
Allard + Champoux modified
ZORBA is a Windows based computer program for predicting the sound absorption of common acoustic materials such as fiberglass, mineral wool or polyester. The effect of perforated or slatted coverings can be predicted as can that of panel absorbers. The properties can be predicted by knowing the flow resistivity of the material and its thickness and the dimensions of the slots or perforations. The flow resistivity is a measure of the resistance to steady airflow and can be readily measured (ASTM C522) or for many materials can be estimated from the density and fiber diameter. Various models for predicting absorption have been developed over the years.
ZORBA gives a choice of different models but by default uses Allard and Champoux’s model (JASA Vol 91 1992) which is the most accurate simple model currently available for predicting absorption. The model is accurate for high porosity materials (i.e. most common acoustic absorbers) when predicting normal incidence absorption. The program has the unique ability to predict random incidence absorption taking into account the variation of absorption with angle of incidence and the diffraction by the edges of the material. Within limits this will give a good estimate of the absorption that would be measured in a reverberation chamber . The performance of slot absorbers, perforated facings and panel absorbers may be predicted by entering the physical dimensions of the slots or holes. A combination of two materials of different flow resistivity and thickness can be modeled.