Tue Jul 04, 2006 4:19 am
ACA P-15 alerting frequency = 450 Hz
ATI RHPSS16 alerting frequency = 460 Hz
Sentry sirens typical alerting frequency = 460 Hz (some are dual-tone 460/920 Hz)
Whelen WPS-2800/WPS-2900 alerting frequency = 465 Hz
ASC T-128, T-121, T-112 alerting frequency = 500 Hz
Federal Eclipse series (8 and NH) alerting frequency = 520 Hz
Typical T-bolt 1000 alerting frequency = 550 Hz
ATI HPSS16 or HPSS32 alerting frequency = 550 to 575 Hz
ACA P-10/ASC T-135 (P-50) alerting frequency = 465/698 Hz (dual-tone)
Federal 2001SRN-A alerting frequency = 705 Hz
Federal 2001SRN-B (since 2003) alerting frequency = 790 Hz
Federal Modulator alerting frequency (typical) = 850 Hz to 1020 Hz
These are FACTS taken straight from the vendor manuals. Now, WHO'S got the high pitched sound that doesn't travel very far?
As far as the electronics versus electro-mechanicals are concerned - the advantages and disadvantages depend on what you want to use them for. Yes, electronics tend to be more efficient so they draw less power to make the same sound output. AND, if you live in a location where power outages are frequent and prolonged, then electronics can last longer on battery power. But for most locations, that doesn't matter much since the event that took aout the grid should be well understood as having already occurred by the local populace. Any siren with battery back-up should be capable of operating at least 24 hours on standby followed by 15 minutes of full power output. Electronics can be on standby for several days typically followed by 15 minutes of full sound output.
As far as complexity is concerned, the least reliable part of the siren is the rotation function (or in the case of electronics, it is better described as oscillation). That goes for T-128's, 2001's, Defenders, Vortex, HPSSR16, WPS-4000 series, whatever.
If I don't need voice function, then give me omni-directional electro-mechanical sirens - ANYBODY's - over the "stereos on a pole." The E-M omni's are simpler, and far more rugged. IF I realize they are going to be up a while, then I spend the extra bucks to get stainless steel housings, etc.
Electronics are far more sensitive to environmental effects than electro-mechanicals. As far as equipment life is concerned, electronics may be capable of 30 year design life, but the vendors don't tend to keep the parts in stock that long. Somewhere at the 15 to 20 year point, if you want to keep the electronics, you will have to replace their guts because you won't be able to get the original replacement parts anymore.
One other advantage of electronics, however, is that they tend to be modular so if I blow a speaker-driver, I still have close to full sound output.
For the battery back-up sirens, as sure as God made little green apples, the batteries will be the weak link because people will not do the maintenance and testing necessary to keep them in top condition - nor will they want to be replacing them every 3 to 4 years. Municipalities are famous for their "penny wise, pound foolish" ways.