TY  - JOUR
A1  - Abel, Markus
A1  - Bergweiler, Steffen
A1  - Gerhard, Reimund
T1  - Synchronization of organ pipes : experimental observations and modeling
N2  - We report measurements on the synchronization properties of organ pipes. First, we investigate influence of an external acoustical signal from a loudspeaker on the sound of an organ pipe. Second, the mutual influence of two pipes with different pitch is analyzed. In analogy to the externally driven, or mutually coupled self-sustained oscillators, one observes a frequency locking, which can be explained by synchronization theory. Further, we measure the dependence of the frequency of the signals emitted by two mutually detuned pipes with varying distance between the pipes. The spectrum shows a broad '' hump '' structure, not found for coupled oscillators. This indicates a complex coupling of the two organ pipes leading to nonlinear beat phenomena.
Y1  - 2006
UR  - http://scitation.aip.org/jasa/
U6  - https://doi.org/10.1121/1.217044
SN  - 0001-4966
ER  - 
TY  - JOUR
A1  - Wegener, Michael
A1  - Bergweiler, Steffen
A1  - Zscherpel, Detlef
A1  - Wirges, Werner
A1  - Gerhard, Reimund
T1  - Detection of elliptical oscillations and monopole breathing of organ-pipe bodies with piezoelectric polymer sensors
N2  - In this paper, a measuring technique is presented for the detection of radial oscillations of tube walls excited by changes in internal air pressure. On organ pipes, the oscillations were investigated by means of piezoelectric polymer films slightly tensioned around the pipe bodies. Employing sensors with patterned electrodes, the well-known elliptical oscillation of the cross section as well as an additional monopole breathing of the organ-pipe body were detected. For the monopole breathing, a close relationship between the pressure distribution of the air-column resonances inside the pipe and the circumference variations along the pipe was observed
Y1  - 2006
ER  - 
TY  - JOUR
A1  - Wegener, Michael
A1  - Bergweiler, Steffen
A1  - Wirges, Werner
A1  - Pucher, Andreas
A1  - Tuncer, Enis
A1  - Gerhard, Reimund
T1  - Piezoelectric two-layer stacks of cellular polypropylene ferroelectrets : transducer response at audio and ultrasound frequencies
N2  - Piezoelectric cellular polypropylene films, so-called ferroelectrets, are assembled in a stack with two active transducer layers. The stack is characterized with respect to its linear and quadratic response in a frequency range from 1 kHz to 80 kHz. A relatively smooth frequency response in the sound-pressure level is found for the individual layers as well as for both layers driven in phase. The piezoelectric response of the two-layer stack is twice the response of an individual layer over a rather broad frequency range. Furthermore, the influence of the preparation conditions on the resonance frequency and the effect of the quadratic distortion on the radiated sound are investigated both for the individual transducer films in the stack and for the stack system as a whole
Y1  - 2005
SN  - 0885-3010
ER  - 
TY  - JOUR
A1  - Wegener, Michael
A1  - Bergweiler, Steffen
A1  - Wirges, Werner
A1  - Pucher, Andreas
A1  - Gerhard, Reimund
T1  - Voided space-charge electrets : piezoelectric transducer materials for electro-acoustic applications
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Wegener, Michael
A1  - Gerhard, Reimund
A1  - Wirges, Werner
A1  - Bergner, André
A1  - Bergweiler, Steffen
T1  - Breathing modes of organ-pipe bodies : experimental detection with ring-shaped piezoelectric-polymer sensors
Y1  - 2003
ER  - 
TY  - JOUR
A1  - Bergweiler, Steffen
A1  - Bergner, André
A1  - Görne, Thomas
A1  - Wegener, Michael
A1  - Gerhard, Reimund
T1  - Breathing modes and sound radiation of metallic organ pipes
Y1  - 2003
ER  -