It’s quite possible that whatever audio editor you are using already has some sort of a pre-set that will get you close to the sound of one of those weather radios.
At any rate, what you are trying to replicate is the “cheap speaker” sound of those radios. Am I correct?
Use a COPY of your original audio to do this…
I’m sure there are several methods to do it, but what I’d suggest you try initially is (either through EQ or a High Pass Filter) get rid of all the low frequency information, then boost the mids just a little and apply a hard limiter. Then boost amplitude a good bit (normalize if you’re in an audio editing program) and even if the audio ends up distorting, that will just add to the illusion.
You’ll have to mess around with the settings of these filters. I can’t give exact specifics.
I hope that helps! Let us know.
Jay Webb
jay@voiceofjaywebb.com
http://www.voiceofjaywebb.com