This circuit uses a CMOS chip and a VMOS FET amplifier for 6W of audio output. 18 W of audio can be generated using a +24-Vdc supply. IC1-a and IC1-b are used as a 1-Hz oscillator.

IC1-c and IC1-d form a 1-kHz multivibrator that is gated by the 1-Hz signal from IC1-a and IC1-b.

The Circuit Diagram of 6 W Warble-Tone Siren