Any ideas for an AppleScript that'll play a sound to keep my speakers awake?

It's trivial to write a script to play a sound every 10 minutes:

on idle
	beep
	return 10 * minutes
end

Save that in a Script Editor document with the 'Stay Open' option selected.

Now every 10 minutes it will play the standard system beep (the 'return' value tells it when to run again)

If you want to play any arbitrary sound, you can invoke afplay with the path to the sound file

on idle
	set soundFile to "/path/to/some.aiff"
	do shell script "/usr/bin/afplay " & soundFile
	return 10 * minutes
end idle

You'll need to provide the full path to the sound file to play. You can even record a sound file or movie full of silence, which should be enough to trigger the SoundSticks (if you provide a path to a movie file it will play the audio track).

And here is a 50 Hz test tone for afplay. Some dog whistles peak at 54 Hz, so this is barely audible except to the household canine. 🤓

That 50 Hz hum is low enough, and edited down in duration, that you probably won't notice it. I chose it for the lack of jolt. 🧐