Unless they’ve been acoustically treated (as a vocal booth in a recording studio would be), most rooms have a natural reverb. The word ‘reverberation’ - or ‘reverb’ - conveys the idea of sound bouncing around in an enclosed space. I'm presently using ValhallaRoom and Reverence for reverb duties, but I listened to some YouTube demo's of the UAD Lexicon 224, and it. It functions as a VST Plugin, an Audio Units Plugin, an RTAS Plugin and an AAX Plugin. Lexicon 224 Digital Reverb by Universal Audio is a Virtual Effect Audio Plugin.