Reading the comments on 'Organ Pipe from eBay Auction' I feel
compelled to share the wisdom of Hartmut Ising, who wrote a paper
called "Erforschung und Planung des Orgelklanges" ["Exploration and
Planning of Organ Sound"], Walcker Hausmitteilung no. 42, Juni 1971,
pp 38-57.

Located in an arcane German publication, it is no wonder it is never
cited and probably not even known by all that should.  Among other
things it tells how to select the proper dimensions in the mouth area
and how to estimate the sound power.

One reason this formula is so little known is, no doubt, that pipe-
makers do not start from scratch.  They have their more-or-less secret
tables and recipes from experience that will lead them about right
from the beginning.

Ising's formula puts hard numbers to those voicing recommendations
which you find loosely formulated in the classical literature.
(For instance in Audsley: The art of organ building, or Monette:
The art of organ voicing).

It also involves computation, but in case you are not scared of a
mildly awkward formula, not to speak of SI units, Robbie has put my
writeup on it at

    http://mmd.foxtail.com/Tech/

together with an attempt to make it more accessible by means of a
graphical dimensioning chart.

Johan Liljencrants
Sweden