St David's Hall is Cardiff's main concert venue and conference centre, opened in 1983 and still one of the most acoustically respected halls in Britain. It hosts the BBC National Orchestra of Wales for much of its concert season, as well as major jazz, folk and world music acts. The BBC Cardiff Singer of the World competition — one of the most prestigious classical singing competitions in the world — is held here.
The building is not architecturally distinguished from outside but the main auditorium seats 2,000 and has the kind of warm, clear acoustic that makes it a pleasure to hear live music in. If you are in Cardiff for more than a couple of days, check what is on — the programming is consistently good and tickets are often cheaper than equivalent London venues.