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THE MUSIC TRADE REVIEW
A Discussion of the Fundamental Principles of the Player—The Oper-
ation of the Valve Systems and the Importance of the Various Rela-
tion—The Chief Difference Between the Single and Double Valve Systems.
By this time we are ready to discuss the opera-
tion of the valve systems of a player mechanism
in their practical relations. The requirement is to
control the collapse and rtinrlation of the pneu-
matics according to the succession of musical tones
in any given piece of music. This means some
way of controlling the operation of the valves
which govern the pneumatics, both as to the fact
of thtir functioning and the order in which those
functions are performed.
Note Selection and Valve Operation.
A valve system is at bottom very simple. Es-
sentially it consists of a pouch, a stem of metal or
hood resting just above the pouch and a disc at
the end of the stem. The pouch forms part of the
Boor of a chamber, of which the roof can be
opened or closed by the rise or fall of the disc at
the end of the stem, and therefore by the rise and
fall of the pouch which operates the stem and its
disc. This chamber is large enough to contain
eighty-eight such pouches and valves, one for each
pneumatic. The chamber is kept in a state of
partial vacuum by the operation of the bellows
operated by the feet-treadles. A small orifice, not
much bigger than a needle point, is sunk through
the floor of the chamber into the channel beneath
each pouch. There are, therefore, eighty-eight of
these orifices, called vents or bleed holes.
Plainly, then, if the large chamber be kept in a
state of partial vacuum the channels underneath
the pouches will also be in a state of partial
vacuum, provided those channels be closed at both
ends so that no supply of atmospheric air can be
finding its way constantly into them.
The Tracker Bar.
Lengthen all these channels until you have
brought them to an end as a series of small ducts
stretching across a metal bar, all at equal distances
from each other, and you have what we call a
tracker bar.
The Music Roll.
Arrange things so that the bar can be covered by
a sheet of paper wound on a spool. Then, so long
as that sheet covers the bar, the eighty-eight ends
of the eighty-eight channels will be sealed, and con-
sequently no air will be able to penetrate into the
channels or under the pouches except what may
have been there at first. Suppose, now, that the
bellows be operated. From what was said above
we see that the air in the channels is partially
exhausted. Now, if the roll be made to unwind
from its spool and wind up on another, crossing
the bar as it does so, and if from time to time
perforations be made in the paper, so that here
one and there another channel is uncovered, then
it follows that wherever this happens the cor-
responding pouch is forced up by the rush of at-
mospheric air into it. This rise of a pouch means
also the rise of the corresponding valve, shutting
off the atmosphere from the pneumatic and open-
ing it into the vacuum chamber, whereby its con-
tained air is expanded into the chamber and the
resulting atmospheric pressure on the outside forces
it shut.
Selection.
It follows that in order to get the pneumatics
to operate in accordance with the requirements of
a piece of music it is necessary for the perfora-
tions on the roll to be made in such order, and
each of such length, that the succession of musical
tones produced from the operation of the piano
action shall be as required in the piece of music
which is to be played. This means the arrange-
ment of the perforations according to a definite
scale and definite rules. Each channel of the
tracker bar leads to one given pneumatic, and this
pneumatic operates one special hammer of the
piano, producing always the same tone. Hence
each duct stands for a special note, and a regular
scale can be applied whereby the position of the
perforation corresponding to any given note is at
once visible. The arrangement of lengths and
other details is a part of the art of roll making, of
which we need not speak further.
Systems.
May we digress here for a moment to say a
needed word? The player trade, unhappily, is in
the unfortunate position of having to bring a ma-
chine of considerable complexity into contact with
persons of altogether minus mechanical ability. In
short we have a proposition that ought rightly to
be handled only by trained specialists being in
fact handled by raw amateurs. Is it surprising
that, in the course of the sharp competition that
everywhere must be met and overcome, salesmen
get into the habit of repeating the most ludicrously
inaccurate statements about various technical
points? Not at all. What is more natural, in
fact? Yet the results of this loose thought and
looser talk are really worse than might be sup-
posed, for the reason that it is always somehow so
much easier to acquire a wrong idea or habit than
to oust it later in favor of the right one. A sales-
man who has got into the habit of talking, with
the best intentions, considerable nonsense about
valve systems, for instance, usually ends by be-
lieving the nonsense he has learned to repeat.
Which is unfortunate.
We have made this digression for the purpose
of emphasizing the assertion that the controversy
which has gone on, and is going on endlessly,
concerning the rival relative merits of the one-
valve and two-valve systems is based upon three-
fourths misunderstanding and one-fourth blank
ignorance. When viewed in correct perspective,
one comes to see that there is not the slightest
reason for proclaiming one any better or any worse
than the other. We say this, and shall explain it
below, for the purpose of introducing the reader
to a right understanding of the subject, to the end
that his own ideas may be clarified and he may
cease from making silly statements on the subject.
Two and Two Make Four.
That is a simple statement, but half the trouble
in the world would be over in a minute if every-
body really put into practice this truth. Let us
apply it in our present case. The two valve sys-
tems operate for the same end, namely, to govern
the operation of the pneumatic. Both systems op-
erate primarily through air delivered at the tracker
bar by atmospheric pressure against partial vacuum
inside channels. Now, the difference is just this:
In the one-valve system the air pressure entering
at the tracker lifts a pouch, which lifts a valve,
which directly controls the pneumatic. In the two-
valve system the air lifts the pouch, which lifts
the valve stem, which then uncovers another pas-
sage whereby atmosphere from another opening,
not at the tracker, rushes under a second pouch
and lifts or pushes forward a second valve stem.
It is this second valve which operates the pneu-
matic.
Now let us put aside for all time all the nonsense
we have ever talked or even heard about this mat-
ter. Look at it as a matter of plain mechanics and
you will see that the question is purely one of con-
venience and that there is not a reason in the
world for preferring one system above the other,
except with reference to the features of some one
particular case. In other words, one system or the
other may be the better for one particular case;
but it is absolute folly and futility to claim funda-
mental advantages for either, as we shall now see.
The mechanical reason for using a second valve
naturally lies in the nature of the forces operating
the first valve. These forces are derived from the
pressure of the atmosphere impinging on the par-
tially exhausted column of air in the tracker duct.
The duct can only be of a given size, although
some slight modifications are possible; but prac-
tically the efficiency of the single-valve system
must depend upon whether the valve is at once
light enough to work rapidly on the flow of air ,
through the tracker, and large enough to uncover
a sufficiently big port in the pneumatic. The sec-
ond valve is introduced when the single valve fails
to meet these requirements.
As to why the requirements should not be met
in any case, this again is not a question to be set-
tled offhand. Plainly, on the one hand, the second
valve means a second vacuum chest; and that
means a larger quantity of air to be partially ex-
hausted. On the other hand, it also means more
expense in building, unless inferior methods and
materials in one case overbalance superior methods
and materials in the other. So it is plain, anyhow,
that the two-valve system is only adopted because
a lot of people have come to the conclusion, after
working it out, that it is better. But we must argue
also that in the beginning of the player construc-
tion was so defective generally that all parts were
unduly cumbersome and bulky. Naturally, with de-
fective bellows and leaky chests—meaning low
vacuum—and large parts—meaning weight—the
two-valve system was required, simply because the
amount of air which can be got down under a
pouch through the opening of a primary valve is
much larger than can be got through the tracker
direct. When parts are too heavy and vacuum low,
therefore, the two-valve is necessary Since those
days, of course, everybody has improved methods
immensely; yet conservatism undoubtedly holds
some to methods really no longer necessary, pot
wrong, but too cautious for to-day.
The two-valve system, then, as against the single
valve, is a proposition in which the merit must be
judged on each individual case. Because your
player has two valves that probably proves only
that such a system fits in best with the methods of
manufacture adopted by the designer and maker.
It does by no means imply that the system a priori
is any better, for the man across the street may
have a player in which the single system is used
and is giving perfect satisfaction. That player
must not be condemned until the facts are known.
Then it will probably be found that his player is
better built with the one system and yours better
with the other.
1 hat is the philosophy of the valve controversy.
Those who want to go deeper can use the facts we
have given and work out their own conclusions.
Much valuable information on the point at issue
will be found in "The Player-Piano Up to Date,"
published by this office.
Royal
Music
Rolls
There are all
kinds of music
rolls and ROYAL
ROLLS.
Royal rolls are cut in
conformity with the estab-
lished standard measure-
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You won't know roll satisfaction
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Royal Music Roll Co.,