•The siren loudspeaker will consist of multiple high efficiency horn-compression driver modules to provide the required Sound Pressure Level at 30m specified. These horns-driver modules are assembled in the form of a vertically stacked array.
•The prime direction of sound radiation of one bank is diametrically opposed (180°) from the prime direction of sound radiation of the other bank
•A frequency difference between the sounds emitted from the opposing banks of horns generates a perfect Omni-directional horizontal radiation pattern at any frequency in the range 200Hz to 1000Hz. (± 6dB up to 2000 Hz)
•Each of the radiating horns may use a commercially available electrodynamic compression driver to avoid single source suppliers of this component.
•The horn-driver combinations will allow 100W incident electrical power.
•The individual horns of the siren head are attached to a strong steel pole in such a way that no accumulative mechanical stress from vertical or horizontal forces is applied to any single horn. Such forces will be absorbed by the steel pole, designed in accordance with the current practice of structural engineers.
•Any future increase in the number of horns in the siren head shall be made simply by attaching these to the central pole, above or below the initial horns.
•Installation of any additional horns does not require dismantling of the existing horns or removal of their electrical connections.
•The individual horns will be attached to the steel-supporting pole by strong clamps and steel bolts.
•In addition to the above standard horn-mounting configuration for Omni directional radiation, Single Horn clamps permit the horns to be individually oriented in any desired direction, with no limitation in angle and no pre-determined angular steps, so that the actual radiation pattern can be optimized to satisfy specific local site conditions. [Compensation for prevailing wind, reductions of sound overspill into adjacent areas etc].
•The area of electrical contact between these clamps and the steel-supporting pole is large to provide a low impedance path for any high currents induced by lightning discharges.
•The electrical cables that connect to the compression drivers is routed inside the steel supporting pole to provide mechanical protection and protection against high voltage fields induced by lightning discharges.
•These connecting cables are protected up to the actual compression driver. A robust connector is provided permitting easy replacement of the compression driver.
