Have you ever been in a restaurant in which your companion's voice is lost in the chainsaw amalgam of everyone else's? It's all so unnecessary, it turns out. A few simple boxes of tricks, a couple of tapestries on the wall, maybe even (gasp) a carpet, and the problem is solved. It's called aural architecture, and it's becoming a factor in designing buildings.
The restaurant effect might be deliberate, done so we can savour the buzz. That's partly the case in the lobby of the Boston Symphony Hall, where the acoustics are such that you can hear both your own conversation and snatches of other people's – "various blends of connectedness", as the music critic Richard Dyer told presenter Trevor Cox in Sound Architecture: The Spaces that Speak. Dyer's in love with the Symphony Hall auditorium's sound signature, and even has his favourite spot, where there's a perfect balance between clarity and reverb.
Our ancestors knew all about this without any PhD theses on psycho-acoustic awareness: at the Constellation Center in Boston they've taken sonic fingerprints of 1,000 buildings around the world, and as the acoustician Barry Blesser says, the old-timers "seemed to have figured it out". He talks about Notre Dame, where the double-sided choir box and the tilted stalls encourage an enveloping acoustic, "like you're buried in sound". All the waves are focused towards the altar, and just in front of it there's a spot, "a transcendental sound space", that "puts you in a kind of religious zone".
For all Cox's enthusiasm – he visited Britain's first open-plan school, in Bermondsey, south London, as well as Ground Zero, where they're trying to construct an "acoustic oasis", and the Sound Lab at MIT, where you can listen to the design of a building before it's built – he didn't quite pin the subject down. We needed more examples. There wasn't enough detail, yet paradoxically the better approach might have been fewer words and more sounds. It was all interesting stuff, but for a radio programme, it was a trick missed.