Ask an expert: Clapping, echoes, bass reflections and related stuff

Why do some people enter a listening room and clap their hands? What are they hoping to find out? If they find out, then what do they do? Should I move my system into a basement? Solid walls and no bass boom – right? Now I am doing it. I have no idea why. Help.

My guess is that they are looking to hear echoes and reverb. Complete waste of time really – unless you are an experienced acoustician. Okay, so they hear reverb and echoes. So what? Is that a good or bad thing? If it’s bad (a subjective response at best and entirely lacking in objectivity), then what?

Apart from anything else, the very act of clapping, at best, can only indicate high frequency reflections. What about the bass? I’ve yet to find anyone who can deliver bass from a hand clap. So, what’s to be done?

Well, some audiophiles install thin acoustic foam all over their walls, mistakenly believing that is sufficient. By doing this you won’t hear any reverb or echoes. However – these physically thin treatments can’t control low frequency reverberations or reflections.

Some audiophiles know this through experience and/or instinct. And so they look for a room with walls made of brick or concrete. That’s not very clever either because as they eventually discover, such rigid walls are especially prone to this ringing. Now I’m no acoustician. I may indeed have over 30 years of listening to innumerable high-end systems that claimed to deliver (and sometimes did deliver) outstanding sound – but I’m not an acoustic expert. Having said this, what would I do?

First, despite some wonderful subterranean music rooms I’ve visited in the USA, quite frankly I find listening to music in a room without natural daylight to be unpleasant after a while. It’s not that I’m claustrophobic. Rather, I feel that listening to music totally isolated from the natural world is, well, a bit odd.

Perhaps even odder is the fact (and I really can’t get my head around this) listen to music played back in a recording studio, which usually have no windows at all, not to be uncomfortable in the way I’ve previously described.

Anyway … if it were me and if I could be bothered (assuming I was troubled by echoes and bass reflections, which I’m not) then I’d build a new plaster board wall a few inches inside the brick wall behind where I sit (filling the space with fibreglass). It’s not perfect, but it works. Not all 4 walls please note, just the wall behind me. Oh yes, I nearly forgot. I’d give up all that clapping nonsense. I really would.

Howard Popeck hp@no-alibi.demon.co.uk