Merged compressed-sensing onto compressive-sensing because there are many more compressive-sensing than compressed-sensing questions (88 vs 16) and all 16 compressed-sensing are double-tagged with compressive-sensing.
Also made compressed-sensing a synonym of compressive-sensing, it shouldn't reappear.
You're right, these are synonymous.
I've created a synonym suggestion, and users with a few answers on the tag can vote for it.
I believe since this is really just a matter of expanding an acronym, a moderator might be able to expedite the process.
you're probably right in regard to this forum. if it was more of a hardcore audio DSP forum, i might think that audio-processing, audio-analysis, and audio-synthesis are three different functions.
but put it all under audio, i think that's good enough and i wouldn't wanna see any tag inflation happening here.
OK, I've made the change you suggest.
Older Answer Below
I'd be tempted to go the other way: keep adc and dac and make the longer forms synonyms. Mainly because the shorter forms include "c" (for convertor), and adding that to the longer forms would make them a little long.
You can always set the text-transform property in a personal stylesheet, for example
switches all those tags to nice uppercase. Beware: this switches all tags. It should be possible to limit the change to dsp.sx via @-moz-document.