This circuit with the 555, was obtained in a 90s American documentation. The signal must be applied to a good amplifier. The sound is similar to that of a police siren.
Two operational are used on this triangular-rectangular oscillator suggested by Motorola in its...
This circuit from a Popular Electronics from the 90's can generate signals from 0.03 Hz to 3 kHz...
With 8 to 30 V power supply, the output power depends on both the voltage and the load. The...