In MMDigest 990322 Craig Brougher wrote:

> Naturally, everybody can hear the stoppered pipes or ranks
> that cannot be anything but wood, ...

Actually, any rank, open or stopped, can be made from either wood or
metal, except those with a name like "Holzprinzipal", where the name
"Holz" means 'wooden'.  Compton theatre organs (UK) were made with all
pipes, including the Tibia Clausa, made of metal.

In the USA, Wurlitzer used stopped wood pipes for the bottom notes
of their Tibias, and then switched to stopped metal pipes for half an
octave before topping the rank off with open metal pipes.  Quintadenas
are almost always made of capped metal pipes.  Robert Morton, for one,
used ordinary wood stoppers in the bass octaves of their quintadenas,
and I believe that Hillgreen-Lane did, also.

> Voicers have long attempted to make metal pipes sound like wooden
> pipes.  You may come very close to it, and I think that a good voicer
> like Dave Junchen would have agreed.

Actually, _many_ people agree.  I've a Tibia Clausa, made of redwood
by the Murray M. Harris organ company. (No, it is _not_ for sale... ;-)
Redwood Tibias made by Harris and their successor Robert Morton are
very much in demand because the material they are made from (in addi-
tion to their scaling, of course) gives them a noticeably 'sweet' sound,
much nicer than the identically-scaled fir or poplar Tibias made later.

The only difference in the ranks is the material they are made from.
The wind pressures are the same.  The only difference is the type of
wood, but the sound is markedly different.

Regards,

Bob Loesch
http://www.jps.net/rrloesch