The ATI Soundblaster HPSS was an electronic outdoor warning system manufactured by Acoustic Technology, Inc that is used to alert the surrounding populace of tornadoes, hurricanes, severe thunderstorms, fires and so on. The recent HPSS systems use high-powered electronic speakers, which can be independently arranged to provide directional or omnidirectional coverage, depending on installation. The HPSS16 provides up to 1600 watts of continuous power to drive up to four 400-watt speaker units, whereas the larger 3200-watt HPSS32 can drive up to eight 400-watt speakers. Like other electronic outdoor warning systems, they can also be used as public announcement systems, and can play a number of programmed tones. Options include solar-powered operation and pre-recorded voice messages. Sometimes these high-powered speakers play the Westminster Chime. The series was discontinued in 2018.
Areas known to use HPSS systems
San Francisco, California - This system is unique, in that it features the sound of the decommissioned Federal Signal STL-10 sirens that the HPSS units replaced
Pensacola NAS, Florida, ATI HPSS16, the sirens on Pensacola's navy base are mostly used for tornado warnings and they play the colors in the morning and evening. When a warning is issued, these siren sound ATI's version of wail signal during tornado warnings. Attack signal or other signals have not been used yet. These siren are silently tested on Fridays.
Arnold, Missouri 7 ATI HPSS32 units which replace the old Whelen WPS 3016 Sirens.
Ketchikan, Alaska maintains a system of 3 ATI HPSS32 units which are tested audibly on the 15th of the month at noon. These sirens are used to warn for tsunamis or in the event of a dam failure.
Problems and criticism
Many deployed HPSS systems, with the exception of the most recent models, used a 1000 Hz Sine wave tone, which some allege is not sufficiently distinct against very noisy backgrounds, or over acceptable distances. More recent HPSS units use a lower-pitched 575 Hz tone which has given adequate results. In San Francisco, many of their HPSS units have the tones of a Federal Signal STL-10 siren, which was one of the sirens used by San Francisco until the whole siren system was replaced with HPSS systems. While this added voice capability to San Francisco's warning network, it has also caused some reliability problems as the comparatively deep-pitched growl of these tones can damage the speakers when playing at high volume. However, this may not necessarily be the fault of the speakers used, as few electronic speakers can tolerate playing such low-pitched, bass-rich sounds at high volume levels for extended periods of time.
