Research Article
Active Noise Cancellation for Ventilation Ducts Using a Pair of Loudspeakers by Sampled-Data Optimization
Table 2
Sound pressure level at each grille.
| | Grille | Sound pressure level () [dB] | | Without control | With control | | | Case (a) | Case (b) | Case (c) |
| | No. 1 | 34.2 | 33.0 () | 32.5 () | 32.1 () | | No. 2 | 40.4 | 38.8 () | 37.4 () | 37.3 () | | No. 3 | 31.9 | 30.5 () | 28.9 () | 29.2 () | | No. 4 | 41.2 | 39.1 () | 37.1 () | 37.2 () |
|
|
