Double-glazed windows have a poor transmission loss at low frequency. Since the passive means are more or less exhausted one could think of using an active controller to increase the transmission loss. In the work presented here two speakers in the cavity between the panes are used as actuators. A modal model is derived and validated with data from a laser scanner and measured transfer functions on the structure. From an analysis of this model it is shown that for certain configurations of the double wall panel some modes of the coupled system are uncontrollable and unobservable by speakers and microphones in the cavity, thus limiting the achievable controller performance. This theoretical result is verified by feedforward control experiments on two types of double-glazed windows. For the fully controllable window the transmission loss achieved by the active controller is about twice as large as for the window with uncontrollable modes.
|Title of host publication||Proceedings of the 17th International Congress on Acoustics|
|Subtitle of host publication||Rome, September 2-7, 2001|
|Place of Publication||Belluno|
|Publisher||International Commission for Acoustics|
|Number of pages||2|
|Publication status||Published - 2001|
|Event||17th International Congress of Acoustics, ICA 2001 - Rome, Italy|
Duration: 2 Sep 2001 → 7 Sep 2001
Conference number: 17
|Conference||17th International Congress of Acoustics, ICA 2001|
|Period||2/09/01 → 7/09/01|
Kaiser, O. E., Agung Julius, A., Pietrzko, S. J., & Morari, M. (2001). Uncontrollable Modes in Double Wall Panels. In A. Alippi (Ed.), Proceedings of the 17th International Congress on Acoustics: Rome, September 2-7, 2001 Belluno: International Commission for Acoustics.