Harvey Chao asked:

> Do "reed stops" actually have a vibrating physical element/reed,
> or is it all how the pipe is physically arranged that produces
> a "reed" voicing ?

The reed stops on a pipe organ do indeed have a vibrating physical
reed, usually made of brass.  The 'pipe' of a reed pipe functions as
a low-Q resonator, selecting a range of harmonics from the series
produced by the reed.  There are some nice drawings of the construction
of reed pipes on the web at  http://junior.apk.net/~cam/pipe2.htm

Paul West