The Addressable Low Frequency Sounder Base (PAD300-LFSB) is a sounder base that may be utilized in a variety of applications. The base has a locking feature for the detector that may be used or removed in the field. Once the head is removed, the sounder is accessible in the bottom of the unit. The PAD300-LFSB low frequency sounder base is designed to meet NFPA 72 sleeping space requirements to produce a frequency of 520 Hz +/- 10% with a square wave. It is shown that a lower frequency, centered around 520 Hz, is the ideal to awaken sleeping occupants, even those with mild to severe hearing loss. The base has an independent sounder module that may be programmed as a single station, zone or all call sounder. The PAD300-LFSB passes through the sound pattern sent to the sounder, therefore it may reproduce in any pattern the power supply provides. The PAD300-LFSB does not consume an address on the loop and is fully programmable to operate with any input. Once activated the sounder will also follow the input from the power source and de[1]activate accordingly.