I recently bought an ADT RX7c siren and it is probably the most painful siren I have heard. It has a relatively low power consumption at <150ma, and a 90db output. It seems to be just as loud as an Ademco 747 or Wave 2, but with the frequency sweeps happening 5 times as fast. I have heard the ATW sirens have a similar output. Any others like this?
Sorry this reply is almost 8 years late.
The loudest siren I have ever heard would probably have to be the ATW terrier piezo siren. It can accept anywhere between 9 and 14 volts and that also charges the loudness. At 14v, it is INSANELY loud. It is even painful through walls. It is about 120db at maximum power.