| 摘要 |
An acoustic annunciator which includes resonating cavity, a piezoelectric element, and a folded horn which are each selected to have a different resonance frequency so as to expand the frequency range of the output of the annunciator. The folded horn includes a cone defined by a main body portion and an outer horn which is rotatable and axially displaceable with respect to the main body portion. The outer horn is designed to rotate to prevent the annunciator from being snagged or caught by objects. The outer horn is designed to be axially displaceable in order to access and remove debris from inside the annunciator. In addition, the acoustic annunciator includes a driver that faces downward during use. This orientation of the driver allows for drainage while preventing the ingress of rain and/or snow.
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