Are any online resources available for ATC recordings? liveatc.net is available, but the voice quality on there, I am given to understand, does not represent the quality of voice available to someone actually sitting in an ATC tower. So I am looking for a source which offers more representative recordings.

EDIT: I intend to use these recordings to evaluate which speech to text engine (Non comprehensive list) works best in the context of aviation, so recordings which best mirror what happens in reality are important to reduce pre-processing.
LiveATC is probably your best shot. The quality you'll get on the stream depends on where the receiver is setup. Since aircraft communications are in VHF or UHF (military) reception is basically within line-of-sight range. This is why often you'll hear the aircraft side of the conversation without hearing ATC.

I would just browse the various streams on LiveATC until you find a good one. OR, if you're near an airport, set up your own receiver!