The current AMICA Bulletin issue (November/December 2017) contains
a thought-provoking essay on page 8 titled "The Shock Absorber." It
takes its title from automobile shock absorbers that protect your car
from bumpy roads, but it refers to mechanisms in band organs and other
wind-operated instruments that cope with air supply problems (primarily
pressure, but occasionally vacuum) when the organ's air supply is not
sufficient to properly play a music arrangement.
Andy is a young arranger and he uses Wurlitzer roll 6877, which he
himself arranged, as an example of what can happen when the demands of
the arrangement exceed the capacity of the organ to pump the necessary
wind to the organ's pipes.
Here are some of the thoughts that Andy's highly interesting essay
provoked in my mind:
1. The only shock-absorbing mechanisms I know of in a band organ are
its vacuum and pressure reservoirs. But the essay seems to imply some
kind of retrofit mechanism. What is it, how does it work, and how
practical is it?
2. Is "wind sag," as Andy calls the problem, only a recent phenomenon
or has it existed in arrangements made in the twentieth century?
3. If twentieth century arrangements don't exhibit the problem, how
was it avoided?
4. Are certain models of band organs more prone to exhibit the problem,
and if so, what are they?
5. Who is more at fault in causing the problem, the organ manufacturer
or the arranger or the organ owner who fails to maintain his organ in
6. How does an arranger know when the demands of his arrangement
exceed the capacity of the model of organ he is arranging for, since
the arrangement cannot be tested on the instrument until it is cast in
stone, so to speak?
7. Answers to the above questions may point to theoretical solutions to
the problem, but what is the best practical solution?
Irondequoit, New York
[ The pump supplies the power, the pipes and leakage consume the
[ power, and a "reserve" (reservoir, accumulator) stores a small
[ amount of power to be released when needed, as for a big but
[ brief chord. The quickest solution to Andy's problem is to reduce
[ the number of pipes playing, e.g., shut off a few ranks.
[ -- Robbie