Re. Matthew Caulfield's article regarding Andy Park's essay, "The Shock
Absorber."  In my own limited experience, with Style 165 or virtually
any vintage pneumatic instrument, maintenance of the pneumatic system
(and all associated moving parts) is more important than anything else.

If the pneumatics are all tight and the pump is at pressure, volume and
'organ sag' I've not personally heard.  I don't think it's a problem
with registration.  The vintage rolls (especially marches) opened all
the stops quite frequently, and a good tight machine won't miss a beat.

On the new cutting-edge music that Mr. Park and others are producing
(which is astounding, in my opinion), very often unique combinations of
ranks are employed that simply were not used by the original Wurlitzer
arranging staff.  In the early days, certainly there were high work
demands placed upon the Wurlitzer arrangers to put out top-quality
arrangements quickly.

I believe there was also probably a mandate of sorts in place that set
standards for "what was and what wasn't" considered appropriate for the
sound that the Wurlitzer business managers felt was the most appealing
and marketable.  It was not for lack of creativity -- the old time
arrangers were highly talented, to say the very least.  It was about
adherence to a set style.  All the old nickelodeon, band organ or
player piano roll companies had individual arranging practices that
defined their sound.

Sometimes it just came down to the musical tastes of a single person,
or very few people.  A good example is the work of the late Messrs.
Ray Deo and William Sabin for the Link Company.  Their own musical
brilliance defines the infectious and unforgettable Link sound.

Again, speaking from limited experience, I do not believe that Mr.
Park's arrangements are beyond the limits of a well maintained Style
165.  There are frequently registers used such as Prestant, loud snare
and octave coupling effects that were not originally part of the Style
165 mechanism (Style 166 includes them).  These do not affect the
playing on a Style 165.

If the effect of 'organ sag' does occur (I believe it's possible,
but have not heard it personally), it must be a very rare phenomenon
on vintage arrangements, to my knowledge.  That would indicate the
newer thinking in Style 165 arranging might occasionally call for
higher operating pressure.  Any pneumatic instrument will ultimately
sag if extreme demands are placed upon the pressure reservoirs.  Only
reproducing pianos and sophisticated orchestrions can routinely make
extreme changes in operating pressure.

There is a practical and very simple solution that will work.
I hesitate to even mention it, as it may horrify owners of original
instruments for fear of added wear on the primary pressure pump and
reservoir.

Many years ago, I thought my upright Ampico simply didn't have enough
vacuum to operate the crescendos and highest volumes.  What I did was
to replace the original drive pulley (maybe 2" wide in the original)
with a larger one, repositioning the motor to keep belt tightness.
This accomplished the goal.  It brought along for the ride increased
wear on the pump and hammers, of course, and operating noise.  So,
at some risk to the main 165 pump bellows and guaranteed additional
mechanical noise, this approach should make any roll play.

The tempo might speed up, and on the 165 there is no manner in which
to slow it down from the roll transmission.  Certainly the machine
contains a Tempo governor; that might have to be adjusted with more or
less spring tension to produce the correct drive speed (around Tempo
50, i.e. 5 feet per minute, to my understanding).  So for what it's
worth, if you need more pressure, push the pump with a larger OD drive
pulley.  You might want to stand back a few more feet than normally.

Frank Himpsl