without acoustic material | with acoustic material | ||||
comparison 1: transmission | comparison 2: reflection | comparison 1: transmission | comparison 2: reflection | ||
one-stage model |
| 89% (4%) | 114% (3%) | 59% (4%) | 83% (4%) |
two-stage model | X = 35 mm | 83% (4%) | 110% (2%) | 71% (3%) | 87% (5%) |
X = 25 mm | 80% (4%) | 125% (5%) | - | - | |
X = 15 mm | 76% (6%) | 130% (7%) | - | - | |
front-slope model | α = 15˚ | 84% (1%) | 100% (6%) | 71% (5%) | 84% (8%) |
α = 30˚ | 86% (3%) | 109% (2%) | 78% (4%) | 96% (3%) | |
α = 45˚ | 86% (2%) | 113% (2%) | 74% (3%) | 91% (3%) |