How these sounds work
Every alert here is one oscillator pushed around by another. The wail is a sine wave whose pitch is swept ±350 Hz by a slow sine; speed that sweep up twentyfold and it becomes the yelp. The hi-lo siren snaps between 450 and 650 Hz with a square-wave modulator instead of gliding. The common thread: pitch that keeps moving. Your auditory system habituates to steady tones within seconds, but a modulated one re-triggers attention on every sweep - which is exactly what an alarm is for. Build your own variants with the sweep generator or layer tones in the multi-tone generator, and convert downloads to MP3 with the audio converter.