The term "acoustic" has shades of meaning these days, depending on the circumstance. A purely acoustic sound is the sound of the instrument, as Greg has said, with only air between it and the listener. Great for the pub, for the home, for the concert hall with decent acoustics. The next, slightly less pure version is where the instrument has to be mic'ed up for broadcasting or recording purposes, or for large listening areas where the natural sound wouldn't carry. Further down the line of acoustic degradation is where the acoustic instrument is fitted with some of electrical pickup.

However much we might prefer the purely natural sound of our instruments - and I certainly prefer playing in a pure acoustic environment or an acoustic session than any other - the fact is that if we didn't have microphones and pickups, we wouldn't have the wonderful world of recording and broadcasting to delve into and learn from. Even the most expensive and superlative mic in the world for an acoustic recording is only going to reproduce what the engineer deems the sound to be - and that's subjective. My sound colleagues at the Beeb in the '60s and '70s were (and probably still are) the best in the business, but they were always aware of the limitations of any recording technology. The only pure acoustic sound you're going to get is when you're sat right next to the instrument itself - but we can't make do with that, can we?

I'd love to be up at Penkhull next Wednesday, but unfortunately (!) I have to be in the Ropetackle Arts Centre in Shoreham in Sussex, listening to Waterson-Carthy. However, when I've come home from that concert, I'll be able to listen to the Boat Band's excellent CDs - not quite "acoustic:", but as near as damn...