does anyone know where I can find 2 audio files that are just beeps at 2 different frequencies (preferably 1000 and 2500 hz, but any would do), as short as possible, like the files are less than a second each?

I could meh into the mic for you. would that work?

Try searching for tone gernerator used for Phreaking, they often have options to select a tone freq and a duration...