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Audible Alarms

Pfannenberg offers a complete spectrum of audible signaling devices. Click the appropriate image below to learn more.


Horns and sirens, also known as "sounders", are tone generators that output an audible signal when a voltage is applied to their input power terminals. Sounders are self-generating - meaning that the tones are pre-programmed into their circuitry and the sound is simply emitted when power is supplied. Sounders are widely used for generating evacuation alarms in the event of fire, toxic gas leak, or chemical spill. Other applications for sounders include machinery start-up alarms, back-up warning systems, process upset signals, heavy equipment movement, moving roof systems, crane movement, and movement of doors, gates, and barriers. Sounders typically generate a variety of tones that can be user-selected. Some units are capable of delivering multiple tone stages. For example, one tone stage may signal evacuation, while a secondary tone stage may signal "all clear" or OK to return.

with Flashing Strobe Light

Horns and sirens with integrated flashing strobe lights, also known as "flashing sounders", are an excellent choice to ensure alarm notification in environments with high ambient noise conditions. For most  units, the flashing strobe light can be wired together or independent from the sounder. This permits a scenario where the sounder can be turned off while the flashing light remains activated - keeping the alarm state present but without the nuisance of a prolonged audible alarm.


Loudspeakers are acoustic transducers that convert audio signals of speech, music, and tone into audible sound pressure waves. Loudspeakers are commonly used with public address systems and other types of warning systems.