> It seems to me that I once heard somewhere, many years ago, that a
> person can't hear an echo from any object closer than 30 feet.  That

I'm not a trained musician* but I discovered just a few days ago that I
could clap my hands with my front door open**, and hear the echo off my
neighbor's house.  And that IS about 30 feet one-way.

> second, that means the shortest echo a person can hear is 55
> milliseconds (55,000 microseconds).
>
> So, it seems to me that the note timing needs to be accurate to about 50
> milliseconds.

OTOH, hearing a 50 ms error in the duration of a note is a lot harder than
hearing two sounds 50 ms apart in time and 30 feet apart in origin as two
sounds.

* I used to play keyboards and the rest of the band used to complain about
my poor sense of rhythm.  But they couldn't find anybody else to do it.....

** Trying to get two grade-schoolers out the door.

--
Too late to write in Wes Groleau for President
http://freepages.rootsweb.com/~wgroleau