Aeolian Company DUO-ART User manual

The
DUO-ART
Reproducing Piano
DI/o-A rt Service Department
The AEOLIAN COMPANY
Aeolian Hall
NEW YORK
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INTRODUCTION
The object of this pamphlet is to give aclear and concise
working knowledge of the Duo-Art Pianola Piano. It is obvious
that in these few pages the aforementioned SUbjects will have to
be treated briefly, and that agreat deal necessarily will have to
be taken for granted that the mechanic already knows, such as a
general
knowledge of pneumatics, and something of electricity.
There is nothing really complicated or intr;'icate about the
Duo-Art and once its principles are understood it will be realized
what a truly remarkable yet simple instrument it is. These
instructions are based upon the upright Duo-Art but would apply
generally to the Grand as it differs only in design.
OPERATION OF DUO-ART DYNAMIC CONTROL
The above subject will be treated under four sub-headings,
namely:
1. Dynamic Step Control
2. Accompaniment Control
3. Theme Control
4. Manual Control
DYNAMIC STEP CONTROL
The Duo-Art dynamic control has 15 steps or degrees of
loudness, and with the fundamental or zero degree, sixteen.
By zero degree is meant the normai Duo·Art. The zero degree
is not called astep. To put it simply, it is the foundation or baSIS
upon which all the higher degr~es are built. As will be explained
later in the Duo·Art test, this zero degree should be as low or
soft, as possible.
The 15 steps are controlled by four holes in the tracker bar
at both the treble and bass ends of bar, above the regular piano
notes. (which are inoperative with the Duo-Art lever "ON") The
four holes at bass end of bar control the accompaniment side of
the expression box and the four in the treble end control the
theme side of the box, in conjunction with additional holes in
the bar (B Theme &T Theme - see diagram No.1 I.
These holes in both bass and treble are numbered from the
outside in (see diagram no. 1) Nos. 1, 2, 4, 8. It will be noticed
that each number is double its predecessor and that IS exactly
what they are in dynamiC power. From the tracker bar, these
dynamic control tubes lead through two cut-off pouch blocks,
(see diagram no. 2, no. 4) and from there to dynamic valve box,
(no. 281 which controls the accord ian dynamics (nos. 26, 27).
Each of these accordian dynamics has four small pneumatics,
each set to collapse a certain distance by small adjusting screws.
Number one in both accompaniment and theme controls the
top or smallest pneumatic of the four and collapses 1/16".
Number two on each side controls the next pneumatic and
collapses 1 /8".
Number four on each side controls the next pneumatic and
collapses 1 /4".
Number eight on each side controls the bottom, or largest,
pneumat ic and collapses 1/2".
This makes a total, with all collapsed, of 15116". These pneu·
matics can work separately or in combinations, or all together.
There are 15 combinations possible with these dynamics.
COMBINATIONS
Step 1. Valves open NO.1
Step 2. Valves open NO.2
Step 3. Valves open No.2 - 1
Step
4. Valves open, NO.4
Step 5. Valves open . _ No.4 - 1
Step 6. Valves open NO.4 - 2
Step 7. Valves open No.4 - 2 - 1
Step 8. Valves open No.8
Step 9. Valves open No.8 - 1
Step 10. Valves open No.8 - 2
Step 11. Valves open NO.8 - 2 - 1
Step 12. Valves open NO.8 - 4
Step 13. Valves open NO.8 - 4 - 1
Step 14. Valves open No.8 - 4 - 2
Step 15. Valves open NO.8 - 4 - 2 - 1
Number 1collapses 1/16 inch
Number 2collapses 1/8 inch
Number 4collapses 1/4 inch
Number 8collapses 112 inch
Total collapse, 15/16 inch.
It will be observed that the accordian dynamics are connected
by a rod at the top of the dynamics to an arm, which when pulled
down opens a knife valve (see nos. 16, 17\. These knife valves
operate over port holes leading to the pump, and the degree to
which these holes are opened determines the loudness of the
playing. The Duo-Art normally is under low pump tension,
drawing in the atmosphere through a spill valve (see no. 18)
'.and exhausting through the pump. This spill valve is completely
cut off by either the accompaniment or theme dynamics at the
10th step. Note connection of spill valve to both the accompani-
ment and theme sides of expression box, and as either knife
valve is pulled down, or opened, by dynamics, they push against
rocker arms mounted on a shaft at the back of the expression
box and the knife valve closes off the intake, or what is termed
"spill".
ACCOMPANIMENT CONTROL
A very important feature of the Duo-Art dynamic control is
that either the accompaniment or theme side of the expression
box can control the entire keyboard, or one can control the bass
while the other controls the treble, or vice versa. This gives great
flexibility of control and the advantages of such asystem are
innumerable. This is a feature found only in the Duo-Art. The
regular player action is divided between the 43rd & 44th notes.
The air is exhausted from player action into chambers Nos.
6&8
of expression box, through flap valves Nos. 9& 10 into
chamber 7, and down through channel 14 into accompaniment
regulator. Here is passes through knife valve 16 and along chan-
nel
to pump where It is exhausted.
The theme secondary valves (11 &12) are normally closed.
As
has been explained, the degree to which knife valve in
the accompaniment regulator is opened determines the loudness
of the playing.
THEME CONTROL
The theme dynamics (No. 27) control the degree with which
accented notes are struck, but it is the valves (11 &12) which
are controlled by holes in tracker (marked B theme & T theme)
operating theme primary valves (5) that determine when theme
shall operate.
The air IS exhausted from player action Into chambers (6 &8)
of expression box. Now theme control holes in tracker bar are
opened admlttrng atmosphere to pouches under primary valves
(5) raislllg
them, and putting secondary valves (11 &12) under
suct lon, causing them to drop and making apassage for air to
channel 13 where it follows to passage 15 into theme regulator.
Here It passes through knife valve (17) and into channel leading
to the pump, where it is exhausted.
-Showing how accompaniment side can control the treble
while theme side controls the bass, or vice versa.-
ACCOMPANIMENT CONTROL OF TREBLE
The air comes into chamber (8) from player action, and theme
valve (12) being closed, passes through flap valve (101 into
chamber (7) through channel (14) Into accompaniment reg·
ulator, through knife valve (16) and to the pump.
THEME CONTROL OF BASS
Arr comes into the chamber (6) from player action and theme
valve (11) being open due to bass theme hole in tracker being
opened, the air passes into channel 13 and then through pas-
sage 15 into theme regulator, on through knife valve 17, and
to the pump. It should be understood that the air once III cham-
ber 7
cannot return to chambers 6&8. Astudy of the flap
valves 9& 10 will be self-explanatory.
MANUAL CONTROL
Other remarkagle features of the Duo-Art Pianol:J P,ano are
the devices for its manual contro!. This system is equalled by
few, if any. and surpassed by none. ThiS system is controlled by
five levers, four of which are in front of the keys and one In the
spool box.

HOW TO TEST AND ADJUST THE DUO-ART
This test will be in aseries of steps (12 in number) and will
cover all points necessary far a thorough inspection and adJust-
ment of the instrument.
Before beginning the Duo-Art test, it is advisable to see that
the piano action is properly adjusted, and a few words here on
that subject would not be out of place.
As is well known, all piano actions are more or less affected
by extreme dampness or by dry weather, which tends to alter
their regulation, thereby making it difficult for the player to
function properly.
Push the hammer rail toward the strings and let it back
quickly. If the hamme~ are slow in returning, the action is damp
and swollen, and must be remedied before going further.
See that there is no lost motion in jacks. See that the hammer
escapement (let-off) is properly adjusted; it should average 1/8"
or less from the strings. Now see that the hammers check about
5/8" from the strings.
These are
the most essential adjustments in relation to the
player action and under no circumstances should they be over-
looked. The more the mechanic knows of piano action regulation
the finer results he can get from the player action. Now see that
there is no lost motion between the player action pitmans and
the wippens on the piano action. See that the stroke on the play-
er is the same as the hammer check on the piano action. This is
a
common adjustment to all player actions and need not be ex-
plained here. Make sure player action is screwed fast; all tubes
are secure, rods
connected, and working freely.
The first lever on key front to the left is called the theme
modulating lever. This lever controls the degree at which theme
notes are played, but unless worked in conjunction with the two
little levers on the key front next to the right, one above the
other, there is no noticeable result. As will be noticed in the dia-
gram, the theme modulating lever is connected to the theme
knife valve regulator, and as the lever is pushed to the right, it
pulls down and opens knife valve (17) but as long as valves 11
& 12 are closed, it has no effect.
These two levers to the right, one above the other, control
theme primary valves (5). The topmost one controls the bass,
and the bottom one, the treble. The modulating lever controls
the degree, and these bass and treble levers, the time, when the
theme shall operate.
The next lever is called the Temponamic Lever. This controls
the tempo by its side motion, and accompaniment expression
by its rotating motion.
By turning this disc to the right, it pulls down on arm, reg-
ulating the knife valve, and opens a port leading to the pump.
The more this port is opened, the louder the playing.
The fifth control is the Duo·Art lever in the spool box. This
lever should be in the "Duo-Art ON" position for all Duo-Art
rolls to be played automatically. To play Duo-Art rolls with
personal expression, have this lever in the central position. For
all other 88·note rolls, have this lever at "OFF".
When the Duo-Art lever is thrown to the center, or neutral
position (or to the OF F position) the little pneumatic (25)
collapses to the point adjusted to by the screw in the moveable
board of t he pneumatic and pulls down on the arm controlling
the accompaniment knife valve, thus making the zero degree
louder when the Duo-Art lever is at "OFF". It has no other
function.
Make sure your test roll measures eleven and one quarter
inches in width. If not, use a roll that does. Have music spool
shaft in center of shifting cam and shifting pneumatics centered.
These are adjusted on shifting rod at back and left of spool box,
by asmall turnbuckle. Now with roll running, adjust tracker lugs
so that they just barely touch the edge of the roll.
TRACKING DEVICE
Step 3.
SUSTAINING PEDAL
Step 4.
Follow tests on roll in rotation. With tempo indicator at 70,
roll should run seven feet per minute. Tempo should cut off
with indicator at extreme left and just start at ten. To run
faster, tighten spring on governor; to run slower, weaken spring.
TEMPO
DUO-ART LEVER "OFF"
Step 1.
See that the gearing is properly oiled, and all set screws
tightened.;
Set the re-roll and play brakes.;
See
that the sprocket chains are not too loose nor tight.
Have all parts on wind motor free but not noisy. Use no
oil on the wind motor.
Pump out tracker bar and insert test rolLin spool box.
-~
ELECTRIC MOTOR, PUMP AND CONNECTIOrzS
Step 2. "
Connect electric cord to conduit in back of piano and make
sure the current is on.
Be sure the motor is proper for local current.
Have motor hand level and with enough tension on belts so
that they will not slip.
See that motor is properly lubricated and set screw in the
pulley is tight.
See that the armature on the motor rotates freely.
Now turn on switch - if motor does not start instantly,
turn off switch or motor will burn out.
Notes on Duo-Art Motors
There are two types of motors used; 1/4 horsepower motor
being used with the six feeder type pump, and 1/8 horsepower
with the four feeder pump. Both motors run at 1150 rpm in
both AD and DC models.
All AC motors are 60 cycle.
To change rotation of DC motors, reverse leads at brush box.
To change rotation of AC motors interchange two leads
coming through bushing cover.
(Step 2
continued}
A fter motor has been inspected, have idler on pump belts
set reasonably tight and on slack side of belts. Now see that
grease cups on pump are filled and turn plungers down a bit to
force grease into bearings. Have pump quiet and time pulsations.
A pulsation is the opening and closing once, of one feeder.
Six feeder type pump should pulse 70 - 72 times per minute,
and the four feeder type 120 times per minute.
To change speed either way it would be necessary to change
the size of pulley on motor. Duo-Art motors are furnished with
proper size pulley to give required pulsations, and before any
change of pulley is made, it would be advisable to make certain
that the voltage of current supplied is correct. -
SPOOL BOX GEARING AND CONNECTIONS
Step 5.
The sustaining pedal is controlled by second hole in bass end
of tracker bar. Flat dampers should clear strings about 1/8"
with pedal on. Dampers should come back to strings between
each bridge in the test roll with tempo set at 70.
It will be noticed that the sustaining pedal, soft pedal and
dynamics get their supply from a pneumatic tension regulator.
This regulator keeps their supply under even tension. This is
done by aspring attached to it. Adjust spring so that pedals
and dynamics work quickly but not noisily. To operate faster,
strengthen spring; slower, weaken spring.
Tracker box gearing and connections.
Electric motor, pump, and connections.
Tracking device.
Tempo.
Sustaining pedal.
Soft pedal. (Hammer-rail liftl
Dynamics.
Accompaniment zero setting.
Theme zero setting.
Notes.
Dynamic Chord test.
Re-roll.
IMPORTANT
STEPS IN TEST
Step 1.
Step 2.
Step 3
Step 4
Step 5.
Step 6.
Step 7.
Step 8.
Step 9.
Step 10
Step 11.
Step 12.

SOFT PEDAL
Step 6.
The soft pedal is contrOlled by the last hole in the treble end
of the tracker. On uprights, rail should move to 1/8" from the
strings. On grands, rail should lift 5/8 from normal position.
DYNAMICS
Step 7.
ACCOMPANIMENT (Duo-Art lever "ON'"
The accompaniment dynamics are operated from the bass
end of tracker bar, above ordinary piano notes, and are numbered
1,2.4,8. These dynamics should operate in order given.
THEME
These dynamics are operated by four holes in the treble end
of tracker bar above piano notes and are the same as accompani-
ment dynamics, 1,2,4,8, and should operate- in order given.
ACCOMPANIMENT SETTING OF ZERO DYNAMIC
Step 8.
Tempo at 80
Warning:
This is the most delicate and Important adjustment in the
entire test and great care must be taken in this adjustment. On
its setting depends the ability of the instrument to play the soft
runs and trills in the music so much desired by all music lovers.
First throw off electric switch and see that regulator springs
(21 &
22) have a little tension, just enough to keep them from
rattling. Use adjusting rings (23 &241. Now see that all tension
springs on the expression box have a little tension on them. See
that the rocker arms controlling spill valve when pushed back
move forward again quickly. Also have arms regulating knife
valves come back quickly.
Have all rods and shafts on expression box free from bindll1g
and squeaking. Avery important thing to watch is that there is
no pressure against knife valve regulating arms, otherwise the
knife valves would open a little and this would make it impos-
sible to properly adjust zero dynamics. Also, there should be no
slack
in arms resting on knife valve regulators as this is just as
bad as the previous condition mentioned. The little leather
adjusting nuts on top of accordion dynamics (26 &27) on rod
to knife valves should not be tampered with as they are set
properly at the factory and seldom if ever need resetting. If the
accordion pneumatics have a little slack or sag, from leather
stretching, it is permissible to take this up on these leather
nuts, being careful not to put too much tension on the rod as
this will open knife valve and this adjustment must be made
before setting accompaniment Or theme regulators as it will
throw out their setting if done after they are adjusted. It is,
however, rare that these nuts will need any adjustment.
Throw on electric switch and observe sottness of notes on
accompaniment tests. It will be noticed that sustaining pedal is
on with the first run of notes, making them easier to play and
off with the next run. Notes should play very softly and on the
next run should miss most at them, Or strike an occasional
note. The third run of accompaniment test is similar to the
first.. If on the second run of ndtes'io accompaniment setting at
zero dynamic all notes strike full, playing IS too loud and must
be softened. To soften, adjustment is made on knife valve adjust-
ing screw (19) and next to this adjusting screw is asmall set
screw (19-a).
This must be loosened before trying to turn adjust·
ing screw or thread will be stripped. Immediately after adjusting
screw is set, tighten lock screw as there 'is a little play in knife
valve shaft unless this is tightened and it would be impossible
with lock screws loose to make fine adjustment.
On uprights, to soften, turn adjusting screws to left, and to
the right to make louder.
On grands it is just the reverse, as the expression boxes are
installed just the opposite way. It takes only aslight turn of the
adjusting screw to make agreat difference.
In making this adjustment always get a blank setting on the
test roll, have motor running and tempo cut off. Watch accomp-
animent regulator pneumatic while setting screw; softening
causes it to open and the reverse causes it to collapse. Adjust-
ment can be gauged accordingly. Patience is required in making
this adjustment, but with a little practice it comes readily. As
will be observed, knife valve has to be adjusted to take first run
of notes softly, but skip or miss most of notes on second run.
TO SET SOLO OR THEME DYNAMIC
Step 9.
The theme adjustment is made on adjusting screw similar to
accompaniment side (see No. 20) It also has aset screw (20-a)
which must be loosened while adjusting screw is being set, and
tightened immediately
The setting of theme side is dependent upon the setting of
the accompaniment as no matter where the latter is set, theme
must be one degree louder. Naturally, the conception of "one
degree" will vary with the individual, but a uniformly safe rule
to follow IS to have the theme regulator pneumatic collapse 1/8"
more than the accompaniment pneumatic. Never have theme
pneumatic even with, nor opened more, than accompaniment.
NOTES
Step 10.
Notes should all strike evenly and softly on thiS test. We will
not go into adiscussion here of the ordinary note troubles as
the mechanic is unquestionably able to handle any trouble aris-
ing
with them.
DYNAMICS CHORD TEST
Step 11.
These chord tests show if dynamics build up evenly. It
accompaniment setting of zero dynamic was properly adjusted,
the first three chord tests will be found very near right. Aslight
adjustment on the regulator springs 121 & 221 is permissible,
but any radical adjustment will throw accompaniment setting
of zero dynamic out, and care must be taken to avoid this.
It may be necessary to meet chord tests to reset accompaniment
and theme zero dynamics a little, The last eight chord tests
show evenness of dynamics in building up, and if pump has been
properly tested and all adjustments made correctly up to this
point, instrument shoVld meet these test.
Followll1g on the" lest roll are two selections of music es-
pecially selected to tryout the responsiveness of the dynamic
mechanism.
RE-ROLL
Step 12.
The re-roll IS operated by the first hole in the bass end of
the tracker bar, and throws the gearing into reverse and cuts off
air to action slide valve (291.
If slide valve (29) did not completely cover the port on re-
roll, the plano would play in the re-roll mode. This seldom
happens,
but It is possible. The mechanic should always rem-
ember ,In locating trouble that there is only one sure m,nhod to
follow without tearing everything to pieces, and that is to lo-
cate
the trouble by aprocess of elimi'nation.