The purpose of these constrictions is to reduce valve noise, which
can be a problem with the faster valve movement characteristic of the
"double" system.  But unfortunately, there is always a tradeoff between
ease of pumping and responsiveness, and quieter valve action.

I have encountered these constrictions in just two of the many double
valve player actions I've worked on over the years.  One was an Auto
DeLuxe Stoddard-Ampico in a Knabe upright.  The constrictions were
within the L-board at the joint, and I drilled out and re-shellaced the
holes with only good results.

The other action was in a 1910 vintage 65-88 note Metrostyle-Themodist
Steinway upright.  Well, I had a lot of trouble with the Steinway.  Its
stack had excessive valve travel, 1/16" to begin with, which was increased
somewhat with settling and usage.  (These valves were designed for
65-note pushup players with 4-tier stacks having pneumatics even larger
than my Steinways.)  Also the pouches were or had become rather porous,
so the valves would lift sluggishly, with so much air rushing around
them that the resulting sudden drop in vacuum level would make some of
them hesitate, causing notes that were intended to play simultaneously
instead play randomly, with single-punch perforations often failing to
produce any sound at all except at slower tempo with harder pumping.

I removed the constrictions, which appeared as a second set of
celluloid bleeds deep within the stack.  Also, I replaced the regular
bleeds with smaller ones, going from #65 drill size to #68.  (The early
Aeolian 88-note rolls were all double-punched, making rolls cut from a
2:1 master appear to have been cut from a 4:1 master.  A single pair of
overlapping punches on an 88-note roll would equal the height of a
single round punch on the 65-note scale.  But Duo-Art and later 88-note
rolls were not double-punched.)

These modifications improved performance, especially with later 88-note
rolls having single punches for repetition.  However, valve noise was
distracting during treble solos, such as the chime effects found on
some Christmas rolls (Merry Christmas, everybody).  The sound of lower
notes would effectively drown out this same valve noise.  As fate would
have it, I sold this instrument before tackling the problem of excess
valve travel.

Now I have another 65-88 note Steinway upright awaiting restoration.
I'm confident that drastically reducing valve travel -- to around
.040"-- will have the desired quieting effect with the constrictions
gone for good.  (Mass producers of player actions tended to set valve
travel higher than optimum, as erring in favor of less would result in
sluggish notes, while more would not prevent notes from playing.)

The stack also has a single thin board at front covering all three
tiers and acting as a sound board to amplify valve noise.  Certain
other Aeolian stacks have individual front covers for each tier,
separated by thick red felt.  So I plan to replace the single cover
with three individual felted ones.  These and other improvements should
result in a player action which will outperform all others.

Jeffrey R. Wood