DUO-ART - Mechanical Music Digest
Contents
1. lt ANA _ CD a 5 2 Se CUI TETN TEA C AaS y AAS aks 0613551063352 0 6296 520106 ee a ane 69 TONS 4 LP gt 5 aN 59 2 279 rors The 255 52 2 DUO ART Mths gt Oy ies Reproducing Piano 5 Ss 853 72 6 al 1 W A lt 5 9 at ase v ois 22 16 ser me ie als A 2 2161 2 9 5 7 its 2 Te ais 0 Sis 2 2 ES J al pe 93 54 soll 2 514 Pan 614 s 579 a fain 42 a 26 GNET ce Ei 55 Duo Art Service Department 625 ar The AEOLIAN COMPANY Be 5 el Aeolian Hall E Sal 9 eT CUE NEW YORK Nid 1 5404 vir PRO 53 ca al WL oe I UE S EREN AA EIAN EE The DUO ART PIANOLA PIANO PRELIMINA2. Screw No 8 is a lock screw and must be loosened before it is possible to adjust the movement of the knife valve through the medium of screw No 7 Failure to loosen screw No 8 is apt to damage adjusting screw No 7 After the arpeggio test is set correctly tighten lock screw No 8 In the upright model turn screw No 7 to the left to make the tone soft and to the right to make it loud On the grand turn adjusting screw No 7 to the left to increase and to the right to decrease the volume In setting the arpeggio test as above observe the movement of the accompani ment and theme regulator pneumatics As the volume increases the pneumatics tend to close and as it decreases they tend to open This applies to both grand and up right models Theme Zero Setting As was stated above the theme zero setting is one degree louder than the accom paniment When adjusting the theme zero setting follow the same procedure as when setting the accompaniment It will be no ticed that the loud pedal is on with the first run of notes on the theme arpeggio then off with the next run this makes it consi derably harder to play than the accompani ment run with the loud pedal off The rea son is that the notes are shorter and conse quently play faster In the second run of the accompaniment with the loud pedal off there are nineteen notes played and in the theme run there are fifteen shorter notes played in one half the space It
3. box and the knife valve closes off the intake or what is termed 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 contro the entire keyboard or can control the bass while the other controls the treble or vice versa This gives great flexibility of control and the advantages of such a system are innumerable This is a feature found only the Duo Art The regular player action is divided between the 43rd amp 44th notes The air is exhausted from player action into chambers Nos 6 amp 8 of expression box through flap valves Nos 9 amp 10 into chamber 7 and down through channel 14 into accompaniment regulator is passes through knife valve 16 and along chan nel to pump where it is exhausted The theme secondary valves 11 amp 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 27 contro the degree with which accented notes are struck but is the valves 11 amp 12 which are controlled by holes in tracker marked B theme amp T theme Operating theme primary valves 5 that determine when theme shall operate The air ts exhausted from player action into chambers 6 amp 8 of expression box Now theme control holes in tracker bar are ope
4. ACCOMPANIMENT AND THEME ZERO SETTING ADJUSTMENT NOTE HOLES amp SVETAINING PEDAL LINE Dynamic HOLES HAMMER R DUO ART Tubing and Schematic Chart CiRCA 1913 1918 i 22 222 cel 4 1 Gov fi Teese TEM Po 9 gt y ERNOR HANDO CONTROL THEMODIST VALVE Tam Disc LEVER MOND CONTROL 209 Nr MOTOR GOVERNOR ESSA SSS SSS TS EEN i N SSSI REGULATING US oe CHEST NS SSSR OS Y TURN TO RIGHT SS 22 E NOTE 1 SHAFT HAS WORM THREAD 4 Tre ay AETIONGOVERNOR Sa ll LOOSEN LOCK SEW FIRS 70 avob STRIPPING er WORM THREAD ae 22 oe rene pe PERSPECTIVE VIEW pP 212 71 07 PEDAL PNEUMATIC CVERNOR 5 SHOW ai ECHAN vroe ce FOR_FOSITIOAL OF AIR PASSAGES NYY yn ig 3 Gover DYNAMICS AS SEE CROSS SECTION FESTON Exprasive KG wr SEE gt s ERECTILE 2 GOTS IOE DET 05 5 ou SIMODIST LINE x PEENI VE MER RAUL Pheunarie Sustaivine PEDAL h PNEUMATIC 3 VA 7774 2
5. a uniformly safe rule to follow s ta 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 a discussion 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 If accompaniment setting of zero dynamic was properly adjusted the first three chord tests will be found very near right A slight adjustment on the regulator springs 21 amp 22 is permissible but any radical adjustment will throw accompaniment setting of zero dynamic out and care must be taken to avoid this 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 should meet these test Following on the test roll are two selections of music es pecially selected to try out the responsiveness of the dynamic mechanism RE ROLL Step 12 The re roll s 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 29 if slide valve 29 did not
6. and cuts down the dynamic power of the expression one half When the dynamic lever is at the Concert position it has no effect on the modulator control box but collapses the accompani ment accordion pneumatic No 8 so that the softest power of expression is power eight Attached to the grand governor tempo control box and to the grand modulator control box are two small pneumatics one No 14 on the modulator box and the other on the governor box Pneumatic No 14 on the modulator box collapses and opens port No 3 on the modulator box and is a pump relief on reroll when these two pneumatics are teed together The spring No 20 on the modulator is set correctly at the factory and set so that the degree of modulation is one half the full volume of the Duo Art This will cor rectly control the action of the accordion pneumatics on the expression box and the action of the sustaining pedal and one should not tamper with it Should it be necessary to get at valves No 10 and No 5 on the modulator box access may be gained by removing the lower cap where slide valve No 4 is situated As these valves are of considerable size however this should seldom be necessary Grand Crash Unit While the expression box of the grand is constructed somewhat differently from that of the upright due to the different designs of the pianos there is no difference in the principles of the expression control The grand expression box
7. arrangement over the older model Quietness of operation is highly desira able it is obtained through the medium of the multiple valve control in conjunction with the pressure regulator A knife valve and a regulator spring are attached to the pressure regulator pneumatic Adjustment of this spring will control the action of the sustaining pedal the accordion pneumatics and the hammer rail lift as regards snappy action and quietness The sustaining pedal and the hammer rail are also controlled through the stop buttons figures 2 and 3 Too great a tension on the regulator spring No 1 will cause noise and valve clatter Too little tension will produce sluggishness of the action this unique control there is regulated and unregulated atmosphere In the upright Duo Art in conjunction with the soft pedal or hammer rail lift is a pallet valve not illustrated The function of this valve is to collapse No 2 accompan iment accordion pneumatic on the expres sion box to compensate for the lost motion created by the hammer rail lift In the grand model the sustaining and hammer rail lift pneumatics are controlled from the mod ulator pneumatic performing the same duty as stated above In illustration page 38 are shown the tubing layout valve control and the position of the repeat slide valve block of the upright Duo Art located on the left side of the roll box In this illustration the switch valve block is mounted on
8. arrows into the accompaniment regulator through the knife valve port and thence to the pump By this it will be seen that air travel is through the accompaniment regulator as long as the theme secondary valves remain against their upper seats thus proving that normally the instrument is under accompaniment control The degree to which the strength of the blow is governed by the movement of the knife valve is controlled by means of the accordion pneu matics 6 5 4 3 31 32 33 and 34 in con junction with the theme secondary valves 16 and 27 The collapsing trava of the accordion pneu matics being 1 l6th 1 8th 1 4th and 1 2 inches as these accordion penumatics collapse The Duo Art continued they control the opening of the knife valve port The greater the area of the knife valve port the stronger the blow given There are adjusting screws on the cross bars of the accordion pneumatics These should not be disturbed as they are set correctly at the factory and should be adjusted only by a set of accurate gauge blocks that are made for that purpose It is also necessary that there be just enough tension on the springs to bring the ac cordion pneumatics back to rest snappily with not too much or too little tension Care should be exercised in this operation if there is too little tension the accordions will not come to 7 rest quickly enough and if there is too much tension the accordions will lag in their collaps
9. control plunger which makes and breaks the circuit manually No 2 shows the power sup ply plug which is inserted in conduit No 3 Always make sure you have A C electric current for an A C mo tor and D C for a direct current mo tor before inserting No 2 plug into No 3 grand Duo Arts not equipped with an electric light but aside from that the wiring is very similar to the upright No shows the electric motor plug 15 The Duo Art continued _ lt Above illustration 5 shows the grand key frame shifting device this was in stalled only in the late model grand Duo Art The Duo Art continued OYNAMIC VALVE BOX Illustration COMBINATION FOOT IMPELLED AND ELECTRIC DUO ART EXPRESSION BOX No 3 COMBINATION FOOT IMPELLED AND ELECTRIC DUO ART EXPRESSION BOX _REFER TO ILLUSTRATION The combination foot impelled and electric Duo Art expression box is slightly different from the standard Duo Art expression box found on page 17 illustration E with treatise on pages 19 and 20 The difference is as follows Spill valve pneumatic with connections and pneumatic which opens a channel between the unregulated supply and the Theme chamber with slide valve opening port The two ports O are used for graduated expression manually with slide valves L and which are connected to t
10. dynamic control ports above the note ports passes through the pouch cut out block thence to the accordion primary valve box from there to each of its respective primary valves then to each of the accordion dynamic pneumatics on the expression box In the upright model the dynamic valve box is assernbled on the expression box frame In the grand model it is attached to the frame of the case as closely as possible The theme valve ports on the tracker bar lead to the theme primary valve box valves Nos 29 and 30 and there to the theme secondaries in the expression box See figures 17 and 18 in Illustration The re roll port and the port in the take up spool lead directly to the repeat and re roll pri mary valve box underneath the key bed These valves control the re roll and repeat pneumatics In the upright model the tube leading from the switch cut out or motor port goes to the left and passes through the repeat slide block where if the slide block is in the off position it con The Duo Art continued nects with the tube leading to the switch valve box figure 8 Illustration O in the 1927 Duo Art Service Manual The sustaining pedal port Editor also known as the loud pedal port on the tracker bar leads directly to the sustaining pneumatic in the grand type and to the pedal regulator in the up right model The soft pedal port leads to the soft pedal primary valve box in the grand model and to the
11. in the upright and spring No 20 illustra tion 41 of the service manual controls the speed of the sustaining pedal in the grand See also above discussion the Modular Control Pneumatic Accordion Dynamics With the Duo Art switch lever at the position the accordion dynamics should collapse in the order Nos 1 2 4 8 on both the accompaniment and the theme sides Should they fail to operate in the given order test directly at the primary accordion valve box removing the tubing leading to the dynamic that is not operating and correct Accompaniment Zero Setting Tempo 80 As this setting is the most important it is essential that on the first arpeggio test the notes should speak evenly distinctly and softly Watch for weak notes in the second run and correct any that are too loud When making adjustments do not The Duo Art continued tamper with the leather nuts on the accor dion dynamic support rod See No 14 illustration page 17 the service manual They are set correctly at the factory and should be left alone Regu lator springs Nos 2 and 35 as well as all other springs were covered earlier in this series Carefully read instructions on this test on pages 23 and 24 of the service manu Adjusting screws Nos 7 and 8 are two different colors one is blue metal and the other is white See illustration F page 17 of the service manual
12. 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 a small turnbuckle Now with roll running adjust tracker lugs so that they just barely touch the edge of the roll TEMPO DUO ART LEVER OFF 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 SUSTAINING PEDAL Step 5 The sustaining pedal is controlled by second hole in bass end of tracker Fiat dampers should ciear 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 15 done by a spring attached to it Adjust spring so that pedals and dynamics work quickly but not noisily To operate faster strengthen spring slower weaken spring SOFT PEDAL Step 6 The soft 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 ACCOMP
13. ing with the result that the knife valve will not open enough as it should Likewise the tension springs on the regulators should not be drawn down to a greater degree than is neces sary but should be just taut enough that they do not rattle Pulling down the tension springs on the regulators is frequently done because of lack of knowledge When this is done it upsets the zero setting of the regulators Editor also read Steps in Test 8 If this operation is carried to the extreme it will ruin the springs for the fine setting of the accompaniment or the theme and it will be impossible to bring down the tone to that softness so much desired by real music lovers If the springs have been ruined the only remedy is new springs Therefore it is suggested that a player technician tread very softly along this path Editor If new springs are being installed it is very important that the correct tension size and gauge of the new springs be established before they are replaced Before going further into the expression box the expression control ports on the tracker bar should be explained so that they may be better understood when referring to the expression box Referring to Illustration in The 1927 Duo Art Service Manual we find the following Re roll Soft Pedal Sustaining Pedal Electric Cut Off Bass Theme Treble Theme No 1 Dynamic Accompani No 1 Treble Theme ment No 2 2 gt 4 gt N
14. lt Ss i A TO PUMP 9 p 7 A 356 2 i p 227 4 ETN 7 55 2 lt a i 1 ANNANN UENEN 555555553 Theme MOPULATOK LEVER 505 DYNAMIC 2052 Va Box N td hea on Foal 212 ez Sib 222 WARS 22222 22 2 25 AR tink 2 Ger he Aa 224 REGULATED 4 2 4 824 Theme 94 142 1 THEME SUPPLY f 2 REWIND LEVEL I J 7 ge 1 ESS gt LOCK SCREW REGULATING SCREW 1 DYNAMIC COLLAPSES A p ELLE CLL LLL LALA LAA Lh fl 4 ae T Ha n INSTRUCTIONS FOR ACCOMPANIMENT ZERO SETTING First see that dynamic lever on extreme left of keyboard is on normal All dynamics should be open Loosen lock screw by turning to the left Start piano and turn regulating screw to the right to make soft to the left loud on the GRAND On the UPRIGHT piano to the left to make soft to the right loud When regulation is completed tighten lock screw by turning to the right locking zero setting Manual No 3
15. older types provision is made for taking care of this adjustment Make sure also that the motor frame does not touch the piano frame as this contact would cause an annoying hum Be sure to pump out the tracker bar ports with a reliable pump USING THE DUO ART TEST ROLL Place a Duo Art test roll on the carrier shaft and with the lever at Play and the tempo at 0 test for quietness Eliminate any undue noise Set the tempo at 70 and with the roll running test the speed of the tempo correct if necessary For this test the Duo Art lever must be at the Off position and the test roll should run seven feet a minute or three and one half feet in one half minute If the tempo is too fast decrease the tension of the gover nor spring If it is too slow increase the ten sion of the spring Refer to illustration 35 of the 1927 service manual The tracking device may also be tested at this time Refer to pages 32 and 33 of the service manual Sustaining and Soft Pedal Test With the sustaining and soft pedals in the position the wedge dampers should clear the strings by at least one eighth of an inch and the hammer rail should move forward to within one inch of the strings In the grand the hammers should lift five eighths of an inch from their normal position Spring No 1 illustration N page 37 of the service manual controls the speed of the sustaining and soft pedals
16. open There is a separate valve box for this unit located in the rear of the case near the sustaining pedal pneumatic Lost mo tion of the shift unit may be controlled by adjusting screw No 6 on arm No 5 This unit is silent powerful and positive in action Preparations for Test Roll Use Before attempting to adjust the Duo Art with the test roll it is absolutely essen tial that the piano action be in proper regu lation See that the hammers travel correct ly that all flanges are tight and that the junction block under the key bed on the grand is tight in order to avoid leakage Inspect all supply tubings for leakage Be careful not to overhaul any of the screws Clean the spool box gearing of dirt grease and oil and inspect the ladder chains for excessive lag Do not squirt oil on the trans mission This is a bad practice as oil is apt to reach the gum tubing and to destroy the body of the tubing Use a good quality of lubricant but not too much of it Do not use oil or grease on the air motor On new set ups or demonstrations be sure that the correct type of electric motor is installed in the instrument and that the voltage and cycle are correct Eliminate all undue motor noises Also see that the belt travels true from the motor to the pump and that it is just tight enough that it does not slip on a full load In the later types of the Duo Art the belt slack is taken care of automatically by springs while in the
17. pedal regulator in the upright model In the later types of Duo Art grands the shifting of the action is accomplished by atmosphere being admitted through the soft pedal port in the tracker bar The raising of the hammer rail is accomplished by placing the modulat ing lever on the control slip in the soft position We will now show how the air travel is changed within the expression box when a theme perfora tion appears on the music roll and what happens when this takes place Referring to the phantom view on page 17 of the Duo Art Service Manual figures 16 and 27 are the bass and treble theme secondary valves Editor The author is referring to Illus tration on page 17 of the 1927 Duo Art Service Manual The same reference may be found in the 1925 Duo Art Service Manual lustration figures 20 and 30 Also on the diagram that is part of the Duo Art Preliminary Instruction Pamphlet the same reference is figures 11 and 12 They are controlled through the bass and treble theme primary valves located in the valve box on the top action at the left of the tracker box The theme primary valve box is shown at the right of the expression box on page 17 Figures 29 and 30 are the bass and treble theme valves respectively and are connected to the secondary valves in the expression box and to the tracker bar As previously stated under normal conditions the theme secondary valves are against their top seats thus compe
18. right and left sections commonly called bass and treble expression controls The control of the Theme notes is independent of the Accompaniment notes Through this control the Theme may be made to sing out clearly above the Accompaniment either in the bass middle register or treble to any degree of expression desired and at the same time any degree of power may be given to the Accompaniment The dynamic perforations at the right and left hand edges of the Duo Art music roll control the dynamic mechanism and by their arrangement and dynamic value determine whether not s shall be controlled by the Accompaniment or Theme regu lator The accordion pneumatics control the move ment of the knife valve heel in both the Accompani ment and Theme regulators At the front of these regulators is a rod attached to the movable board of each pneumatic It is also fastened to the front or toe of each knife valve See rod No 6 in illus tration page 18 This rod conveys to the knife valve the equalizing or governing effect of the regu lator pneumatic and it is obvious that through the use of this ingenious device very fine and delicate cresendos or diminuendos are easily obtained When we speak of the zero degrees in the Duo Art we mean the gradation of loudness attained without the use of the accordion pneumatics which control all of the gradations above zero Their ad justment is independent of the other gradations and will be fu
19. tracker bar at both the treble and bass ends of bar above the regular piano notes which are inoperative with the Duo Art lever The four holes at bass end of bar control the accompaniment side of the expression box and the four in the treble end contro the theme side of the box in conjunction with additional holes in the bar Theme amp T Theme see diagram No 1 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 15 exactly what they are in dynamic power From the tracker bar these dynamic control tubes lead through two cut off pouch blocks see diagram 2 no 4 and from there to dynamic valve box 28 which contro s the accordian 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 Pneumatic and collapses 1 2 This makes a total with all collapsed of 15 16 These pneu matics can work separately or in combinations or all together There are 15 combinations possi
20. 288 OLT 222222 2222272 2222 2 Or ry VALVE BOX bas j a ZA RY gt BEZZA VES 5 _ 3 TREBLE THEMOOIST LINE p 8955 THEMOOST LINE STAINING PEDAL Ling ME ie 1 aa e aaam DIAGRAM For T GRAND REPRODUCE IN ACTION 1925 MODEL lil 1 1 4 2 UNIT To 7 Lown bere PNEUMATIC Sack ETc So 0 O 60 go NOTES PAL IR PAGE SRE 55 Jf 584 Q 2 DINE AVE NOTES ARE USAG AS 7247 OA THIS LE Darron V 47 NO VISION KAIS DINAS DAONA INA ah LIN A ANA NOLAN Det OND Wine 24407 LUNE LON 88 18 38 SG 1 TT TT ganar Ra wae LIND RIO 22777 70 2 5295 IVARAM TON PY 277072 mog E 1 5 1 RAIL The Duo Art Editor Included in Wilberton Gould s series in The Tuners Jour
21. ANIMENT Duo Art lever 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 taken in this adjustment On its setting depends the ability of the instrument to play the soft runs and tritls in the music so much desired all music lovers First throw off electric switch and see that regulator springs 21 amp 22 have a little tension just enough to keep them from rattling Use adjusting rings 23 amp 24 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 binding and squeaking A very important thing to watch is that there is pressure against knife valve requiating 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 sl
22. IND AND REPEAT MOTOR JUNCTION BLOCK REWIND DOUBLE MEMBRANE BLOC TO CUTOFF BLOCK ON REWIND LEVER LEADING NO 2 OR NO I ACCOMPANIMENT DYNAMIC FLY VALVE FOR CUTTING OUT MOTORA AND SUCTION AUTOMATIC CONTROL WHEN FOOT OPERATED NOTE ALL NOS REFER TO RUBBER TUBE CONNECTIONS TO MEMBRANE BLOCK CONTROLLING DYNAMIC PRIMARIES NO 1 2 SUCTION TUBE DUO ART SIDE OF DOUBLE MEMBRANE BLOCK SINGLE MEMBRANE AND DYNAMIC MEMBRANE PRIMARY PRIMARY CONNECTION FOR DYNAMICS TREBLE THEMODIST BASS THEMODIST 7 PEDAL PRIMARY TUBES THROUGH JUNCTION BLOCK SUPPLY TO THEMODIST SIDE OF THEMODIST SUPPLY TO TRACKING DO 2 gt gt lt m y 510 Z gt X gt 6 2 Z 0 J O O gt 10 SUCTION SIDE OF DOUBLE MEMBRANE BLOCK 11 SUPPLY TO CUTOFF BLOCK CONNECTS TO MOTORA 12 amp 14 THEMODIST 13 amp 15 DUO ART THEMODIST 16 LEADS TO GRADUATION CUTOUT VALVES 17 CONNECTION TO RETARD ATTACHMENT FOR REWIND CONNECTS TO RESERVE ON BELLOWS SET SINGLE MEMBRANE BLOCK X S PPIN P11
23. RY INSTRUCTION PAMPHLET Operation of DUO ART Dynamic Control and How To TEST and ADJUST INTRODUCTION The object of this pamphlet is to give a clear and concise working knowledge of the Duo Art Pianola Piano is obvious that in these few pages the aforementioned subjects will have to be treated briefly and that a great deal necessarily wilt 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 intricate 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 Contro 3 Theme Control 4 Manual Control DYNAMIC STEP CONTROL The Duo Art dynamic contro has 15 steps or degrees of loudness and with the fundamental or zero degree sixteen By zero degree is meant the normal Duo Art The zero degree is not called a step To put it simply it is the foundation or basis upon which al the higher degrees 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
24. The Duo Art The Duo Art continued 99 Illustration from the 1927 Duo Art Service Manual page 17 UPRIGHT DUO ART EXPRESSION BOX AND CONNECTIONS 09 00 0 62 030 05 Illustration i 11 2 tA DUO ART OFF 43 PNEUMATICS EXHAUST EDITOR Continuous changes were made to the Duo Art system For Duo Art mechan isms produced prior to 1926 and for additional information on all Duo Art systems refer to 1 1925 Duo Art Service Manual 2 Preliminary Instruction Pamphlet Operation of Duo Art Dynamic Contro and How To Test and Adjust This pamphlet contains additional de tailed information and a more detailed diagram of the Duo Art control system 3 For the com bination foot impelled and electric Duo Art refer to Export Supplement To Service Manual No 3 of 1927 The expression box is different in this type from the standard Duo Art expression box shown in the Illustration No on this page NOTE 1 2 and 3 are included in this publication The Duo Art continued THE DUO ART DYNAMIC CONTROL SYSTEM Refer to Illustration E The Duo Art Reproducing Mechanism is built upon an entirely different mechanical principle than any other device of its kind It is based upon the musi cal principle of dividing the musie musically into Theme and Accompaniment instead of dividing it mechanically into
25. ack 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 amp 27 on rod to knife vaives 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 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 electric switch and observe softness 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 of them or strike an occasional note The third run of accompaniment test is similar to the first If the second run of n tes in accompaniment setting of zero dynamic ait notes strike full playing 1 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 a small set screw 19 This must be loosened before trying to turn adjust ing screw or thread will
26. be stripped Immediately after adjusting screw is set tighten lock screw as there is a little play in knife vaive 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 slight turn of the adjusting screw to make a great 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 w hile 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 a set 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 fouder Naturally the conception of one degree will vary with the individual but
27. ble 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 4 Step 5 Valves open 4 1 Step 6 Valves open 4 2 Step 7 Valves open 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 8 2 1 Step 12 Valves open No 8 4 Step 13 Valves open No 8 4 1 Step 14 Valves open 8 4 2 Step 15 Valves open 8 4 2 1 Number 1 collapses 1 16 inch Number 2 collapses 1 8 inch Number 4 collapses 1 4 inch Number 8 collapses 1 2 inch Total collapse 15 16 inch It will be observed that the accordian dynamics are connected by 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 Ouo Art normally is under low pump tension drawing in the atmosphere through a spill valve see no 18 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
28. completely cover the port on re roll the piano would play in the mode This seldom happens but it is possible The mechanic should always rem ember in locating trouble that there is only one sure method to follow without tearing everything to pieces and that is to lo cate the trouble by a process of elimination DIAGRAM OF DUO EXPRESSION CONTROL 2 ACCOMPANIMENT Theme 3000900004 2 ir SSS SSS BS 3 SSS ES AS am q gt 772777 ZT 2 aaju lt 2 5553 SSS SSS GL Le z2 Eza ZA za S T zzz 772217224 72277 THEME PRIMARY VALVE BOX FIOM BASS WIND CHEST FROM TREBLE WIND EXPRESSION BOX 502255252222 70 5 A N 9 51 N NAI 2226 N LN e 4 2 S or N Z N ACCOM PAN IMENT THEME N N ZEGULATOR REGULATOR N NN oor Q N FAN 4 4 1 5 i 417 lt
29. dion dynamics are collapsed This spill valve is returned to its normal position by the action of a coil spring which should be adjusted just strong enough to give it a positive return motion If it is adjusted too strong it may retard the motion of the accordion dynamics and thus affect the normal expression See illustration J on 28 for the method of connection and its operation The tracking device shown in illustration L on page 32 is simple and positive in action and when understood correctly is very easy to adjust It should not be con demned if it fails to operate correctly It should be remembered that not only this type of tracking device but every other type was tested under many and varied conditions and that when installed in the instrument it did its work The greatest trouble encount ered in adjusting any tracking device is lack of knowledge of the principle under which it operates In adjusting the Duo Art tracking device the power should be on and the track er bar covered with a roll The tempo should be set at zero and the tracker ears moved away from the edges of the paper The track er pneumatics should be centered exactly and the top drive shaft at the right of the spool box should be at center of the shifting cam Figure 8 Figure 1 shows a turnbuckle which adjusts the position of the cam This turnbuckle has left and right threads and is supplied with lock nuts which should always be
30. e pump The spring No 9 controls the Governor Weakening it slows up the speed and strengthening it speeds up the tempo When the Duo Art is in play the reroll port No 4 is closed by slide No 7 and when rerolling it is open making the reroll much faster than if the air had to pass through the tempo port 11 Test No 4 Tempo Test Push Duo Art Lever in Off Position Follow tests on roll in rotation With tempo in dicator at 70 roll should run seven feet per minute or 3 feet in thirty seconds 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 Refer to treatise on Motor Governor page 34 with illustration M page 35 The Duo Art continued UPRIGHT LOUD AND SOFT PEDAL CONTROL Illustration 000080 LOUD PEDAL PORT LOUD PEDAL F4 lt lt DN U LOUD PEDAL PNEUMATIC TRACKER BAR EXHAUST CONNECTION TO EXPRESSION BOX xD SS NS 2020 9 g PEDAL PRESSURE REGULATOR UNREGULATED AIR REGULATED AIR SOFT PEDAL PORT SOFT PEDAL 1 E 7AN AETA PSS lt lt SOFT PEDAL PNEUMATIC UPRIGHT LOUD AND SOFT PEDAL CONTROL Refer to Illustration The loud pedal is controlled from the second hole in from bass
31. either by the accom paniment regulator or the solo regulator The keyboard of the instrument is divided musically into theme or solo and accompani ment in the same manner as if it were played man or Ms ually For example carrying the melody from the bass to the treble or crossing the hands or carrying the melody from the treble into the bass is effected through the accompani ment regulator or the theme regulator There is no duplicate control system in the Duo Art a control system for the bass and one for the treble On the contrary one regulator either the accompaniment or the theme in conjunction with the theme valves may control the entire register In order to understand how this is ac complished it is necessary to understand the travel of atmosphere from the pneumatic stack to and through the expression box and also to know what is taking place during the operation Referring to the phantom view on page 17 of 1927 Service Manual Ilustration E it will be noted that figures 19 and 25 are the main supply from the pneumatic stack to the expression box bass and treble ends Under normal conditions when the theme secondary valves figures 16 and 27 are up against their top seats they cut off air channels from chambers 20 and 24 This causes the atmosphere entering the nipples figures 19 and 25 from the pneu matic stack to enter the accompaniment chamber figure 22 and pass down as indicated by the
32. embered that the levers have a down pull on the heels of the knife valves the same as do the accordion dyna mics and the levers control the movement of the knife valves and the opening of the ports The more the levers are moved from their normal position the greater is the intensity of the suction built up in the regulators and cor respondingly the stronger will be the force of the blow of the striking pneumatic The theme levers control the movement of their respective pallet valves underneath the key bed allowing atmosphere to be admitted through the ports of the pallet valves directly to the pri mary valves instead of through the tracker bar By the use of these levers it is possible to pick out any single note in either the accompani ment or the theme and accent it at will This follows the same principle as the ex pression perforations cut in the Duo Art music rolls The spill valve or atmospheric intake is located in the rear of the Duo Art expression box It is properly adjusted at the factory and should not be tampered with As either the theme or accompaniment regulator in tensities increase this valve begins to close and when the intensity of either regulator reaches the tenth degree it is fully closed remaining closed from this tenth degree through the fifteenth Below the tenth de gree it is either closing or opening as the regu lator intensities are increasing or decreasing being fully open when no accor
33. end of tracker bar and the soft pedal from last hole in treble end of bar The supply to the loud and soft pedal pneumatics is controlled by the pedal pressure regulator the purpose of which is to govern the air pressure operating the loud and soft pedals and the accordion pneumatics on Duo Art expression box Spring No 1 controls pressure oper ating loud soft and accordion pneumatics and should be set strong enough to operate these pneumatics fast and snappy but not noisily Adjusting screws No 2 and No 3 on pedal pneumatic controls lift of dampers and soft rail It will be noted that there are three loud pedal valves The reason for this is to shorten the valve motion insuring quietness and speed in loud pedal operation The soft pedal does not operate as fast as the loud pedal therefore two valves are sufficient 12 for this device Illustrated below the pressure reg ulator pneumatic is a top view of the valve box showing the regulated air and unregulated air chan nels Do not have spring No 1 pulled too tight as the loud and soft pedals will operate in a noisy manner On old instruments where the loud pedal functions noisily shorten the valve travel Test No 5 Loud and Soft Pedals Tempo 70 With loud pedal on wedge dampers should clear strings inch Dampers should come back to strings on each bridge in pedal test for speed Spring No 1 in illustration page 37 controls the speed of the loud and sof
34. has a crash valve unit which acts only when power fifteen comes on that is when all the accordion pneumatics on the theme or solo side are collapsed The action of the crash valve gives a direct passage to the pump and when the crash comes on it cuts around the theme knife valve direct to the pump In this way it causes the maximum hammer blow When the crash valve is set all theme pneumatics should be collapsed valve arm No 6 see illustration page 45 of the Duo Art service manual should be up and the adjusting screw in the arm should just raise pallet valve No 5 Should it not be the case that the adjusting screw in the arm just raises pallet valve No 5 one or two turns of regulating screw No 6 should be sufficient Rough adjustments may be made with regulating screw No 7 and fine adjust ments with screw No 6 Care should be exercised that the upward travel of arm No 7 is not so great that it will act when power fourteen comes on in other words the pal let valve should not rise more than one sixteenth of an inch Key Frame Shift As was previously stated the key frame shift see illustration S the Duo Art service manual is installed only in the grand The Duo Art continued Duo Art and only in the later models In conjunction with the hammer rail lift how ever this attachment permits very fine shad ing of the music The key frame shift oper ates only when No 1 treble end port is
35. he Bass and Treble levers on the keybed when used as a pianola piano The Dynamic or Expression primary Valve Box is divided near the center with four valves on the Theme side and five on the Accompaniment side adding an additional inch accordion pneumatic on the Accompani ment side Nipple is the exhaust supply for the Accompaniment side of the Dynamic Valve Box and nipple D the exhaust supply for the Theme side Further information on illustration may be found in the special supplement to the 1927 Duo Art service manual this sup plement is available through the publishers of this book SUPPLEMENT TO SERVICE MANUAL NOTES CN THE ACTION OF THE DECOY BOX i WHEN THE HOLE MARKED A ON THE TRACKER BAR DUO ART METAL AND THAT MARKED B ON THE SPOOL ARE BOTH EXPOSED THE MOTOR IS PREVENTED FROM CUT OUT RUNNING BUT WHEN EITHER OF THE HOLES GR 15 CLOSED BY THE MUSIC ROLI THE MOTOR COMES INTO OPERATION SHOULD THE MUSIC ROLL PAPER Lt AVE TRACKER BAR WHEN RE ROLLING HOLE STILL BEING COVERED THE 15 PREVENTEO FROM SWITCHING OFF DIRECT FROM THE BAR AS OD ONIHSINANd HWY LYVWHMIA 11026 RETARD ATTACHMENT FOR RE ROLL TEMPO BOX SPILL VALVE CUTOUT FOR REWIND LEADING TO GRADUATING THEMODIST AND CUTOFF VALVE GRADUATED EXPRESSION CHAMBER METAL REPEAT FITTING 4 OTHEMODIS CHAMBER REW
36. is easily seen that more pressure is needed to play the second run of the theme with the pedal off and the shorter notes If the theme zero is then set so that it plays about every other note on the second run with the pedal off the one degree louder has been obtained as described in test No 8 Theme Zero Set ting page 24 of the service manual If both accompaniment and zero settings are proper ly regulated the accordion dynamic chord test which follows will meet the require ments of the chord test in the roll Note tests carefully and also test reroll and repeat in the order given in the service manual Key Slip Control Levers Test key slip manual control levers to see that they move freely and do not bind In extremely damp weather the bushings may become swollen and the levers may bind This binding must be eliminated as any constraint on the freedom of these levers will affect the movement of the knife valves in both the accompaniment and theme regulators Now a final word about any and all ad justments and regulations of the reproducing mechanism know what you are doing and why you are doing it Be honest with your self if you do not know how to make the adjustments do not attempt them It will be safer KXK Editor This concludes Wilberton Gould s discussion of The Duo Art On the next pages will be found relevant reproductions from The 1927 Duo Art Service Manual and other illuminating illustrations of
37. is thrown to the center or neutral position or to the OFF position the little pneumatic 25 collapses to the point adjusted to by the screw in the moveable board of the pneumatic and pulls down the arm controlling the accompaniment knife valve thus making the zero degree louder when the Duo Art lever is at has no other function HOW TO TEST AND ADJUST THE DUO ART This test will be in a series of steps 12 in number and will cover all points necessary for a thorough inspection and adjust ment of the instrument STEPS IN TEST Step 1 Tracker box gearing and connections Step 2 Electric motor pump and connections Step 3 Tracking device Step 4 Tempo Step 5 Sustaining pedal Step 6 Soft pedal Hammer rail lift Step 7 Dynamics Step 8 Accompaniment zero setting Step 9 Theme Zero setting Step 10 Notes Step 11 Dynamic Chord test Step 12 Re roll IMPORTANT Before beginning the Duo Art test it is advisable to see that the piano action is property 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 hammers are slow in returning the action is damp and swollen and must be remedied bef
38. l 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 After 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 TRACKING DEVICE Step 3 Make sure your test roll measures eleven and one quarter inches
39. lling the atmosphere from the pneumatic stack to travel through cham bers 20 and 24 through the flap valves 21 and 23 into chamber 22 down through the channel as indicated by the arrows and through the knife valve port of the accompaniment regulator and to the pump The question may arise How do the secon dary valves remain seated against their top seats As stated above there is a theme primary valve box located on the top action at the left of the tracker box Under normal conditions the valves in this box are at rest or down against their bottom seats Atmosphere is admitted over the tops of the valves passes through connecting tubes and inflates the pouches under the secondary valves thus holding these seco dary valves tightly against their upper seats and preventing any passage of air from the pneu matic stack to the theme regulator The infla tion of the theme secondary pouches just men tioned is accomplished by the action of the theme regulator suction which entirely sur rounds the top surfaces of both theme second ary pouches The moment theme perforations appear on the music roll atmosphere is admitted through the theme ports in the tracker bar to the primary pouches inflating them and raising the primary valves to their upper seats This action cuts off the atmosphere which was ad mitted through the top cups and permits the suction of the theme primary box to exhaust the secondary valve pouches through the bot
40. llustration O on page 38 The Duo Art continued GRAND DUO ART MODULATOR PNEUMATIC Illustration GRAND DUO ART MODULATOR PNEUMATIC Refer to Illustration The Modulator covered by illustration will be found only in the Grand Duo Arts The Mod ulator Pneumatic provides a means whereby the normal Duo Art may be modified or softened with out losing any of the dynamic gradations 16 also acts as a supply regulator for the loud pedal and accordion pneumatics and it equipped with a cutout valve for the pneumatic action on reroll The illustration has been distorted somewhat to show channel No 8 which actually is back of chan nel No 11 With the Dynamic Lever in front of Duo Art at the Concert or normal position the modulator valve No 10 is open and allows the air entering chamber No 13 to pass down through channel No 11 then up through channel No 8 into chamber No 7 where it passes down channel No 6 and up channel No 2 to outlet No 1 then it passes to the pump and is exhausted 0 te N 14 gt M With the Dynamic Lever in front of Duo Art at Soft or modulated position valve No 10 raises and closes channel No 11 The air entering chamber No 13 now passes up through channels covered by No 12 and the flap valve No 16 which is closed when valve No 10 is is now
41. lly explained later The zero degrees might be termed the foundation of the dynamic structure as all of the higher or louder gradations in the Accompaniment and Theme mechanisms are built upon them Each gradation in the Theme registers slightly louder than the cort responding gradation in the Accompaniment mech anism THE DUO ART DYNAMIC GRADATION CONTROL Refer to Illustration E No 1 Zero setting adjusted to test roll 2 Ports open 1 Accordions collapsed No 1 1 16 3 47 2 af te No 2 2 16 4 1 2 1 2 3 16 Gen 4 a No 4 4 16 2600 1 4 as 45 1 4 5 16 a 2 4 2 4 6 16 e 28 0 s 1 24 No 1 2 4 7 16 9 8 8 8 16 10 1 8 No 1 8 9 16 1 ai 2 8 2 8 10 16 12 24 1 2 8 No 1 2 8 11 16 13 4 8 4 8 12 16 14 1 4 8 1 4 8 13 16 15 i 2 4 8 4 No 2 4 8 14 16 16 1 2 4 8 No 1 2 4 8 15 16 The gradations in the accompaniment are con trolled by the four large holes in the bass end of the tracker bar set above the regular note ports See tubes marked 1 A 2 A 4 A and 8 A The Theme gradation control ports in the tracker bar are shown in the lower right hand corner of the illustra
42. n shows the crash primary valve box No 6 shows the connecting arm and screw which is attached direct to the knife valve shaft and as the accordion pneumatics collapse it raises this arm closer to the pallet valve No 5 but until power No 15 appears in the Theme side it should not operate With the regulating screw No 6 this adjustment can be made so that at power No 14 the crash is off and at No 15 it comes and this adjust ment should be made after any regulation of the Theme knife valve When the crash valve operates it makes a channel direct from the pneumatic action to the pump cutting around the Theme knife valve and very quick loud accents can be obtained with this device No 2 shows the supply tube to the crash valve primary No 3 shows the tube which connects to the pallet valve No 5 No 7 shows the set screw crash arm and rough adjustments can be made here of regulating screw No 6 to pallet valve No 5 No 4 shows the atmosphere intake or spill on the grand expression box No 8 shows the spring which pulls the spill valve back to normal No 9 shows the nipple to the Theme secondary valve on the treble side CRASH VALVE GRAND EXPRESSION BOX 4 1927 Duo Art Service Manual Also known as Illustration Q in the 1925 Service Manual The electric wiring on the Duo Art is very simple as the illustration shows No 1 shows the switch
43. n the electric motor controlled by the second hole in on the right side of tracker bar can not be shut off when the motor hole is exposed on MOTOR PORT 71 TAKE UP SPOOL EXHAUST 13 SWITCH PNEUMATIC 9 SWITCH VALVE BOX 000 2 2 id 214 OTN 222 to function and music is replayed With Repeat block No 2 at the off position the block slides over and connects the motor port in the tracker bar tube D with tube C that leads to switch valve in box No 8 Tube C has a bleed This allows Repeat hole in takeup spool that reduces the atmosphere entering tube D through motor port in tracker This bleed however is smaller in size than the bleed in the switch valve so the atmosphere entering tube C through tube D is not sufficient to neutralize bleed switch valve When port No 7 is exposed by music roll atmo sphere enters through tube B which also has a bleed combined with the atmosphere entering bleed in tube neutralizes and overcomes the bleed in the switch valve in Box No 8 and causes the valve to raise thereby collapsing pneumatic No 9 and cutting off electric switch Test No 11 Reroll The reroll is operated by the first hole in the bass end of the tracker bar and throws the spool box gearing into reroll For details see treatise on page 39 with i
44. n dynamics The theme valves deter mine the note or notes that are to be accented by accenting any note or group of notes when ever a direct passage is opened through the theme regulator to the pump If as has been shown the path of the atmosphere can be changed within the ex pression box it is then proved that the theme regulator may control every note in the register While the accompaniment regulator does like wise the theme may accent any note without interference from the accompaniment regulator and may accent any individual note in either the bass or treble action thus proving that this mechanism is truly based on a musical principle and that it will reproduce exactly the perfor mance of the artist upon the keyboard of the instrument Manual control of the Duo Art is obtained by means of a system of levers situated on the key control slip of the instrument Normally they are used only when a roll other than a Duo Art isused and then only with the Duo Art switch in the spool box at the Off position Editor In this Off position 88 note rolls of standard roll width 114 inches may be played These levers give the operator direct control over the movement of the knife valves in both the accompaniment and the theme regulators as well as control over the theme valves Illustration page 21 of the service manual shows one of the regulators accordion dynamics and man ual control lever It must be rem
45. nal on Player Piano Mech anisms is the following article on the servicing of the Duo Art Mr Gould makes extensive reference to the 1927 Duo Art Service Manual in this discus sion especially to Illustration therein Illustrations and sections to which he refers including Illustration E are reproduced at the end of this section on the Duo Art THE DUO ART In the servicing of the Duo Art mechanism it is absolutely necessary that the technician understand the expression system and the prin ciple under which it functions The only tools required are a screwdriver a Duo Art test roll and a musical ear The mention of this last item might seem out of place in this technical series but experience has proven it to be vital The expression box is the heart of the Duo Art through which the artist s musical thoughts may be reproduced and it will be discussed tho roughly here All references made to the expres sion box apply both to the grand and to the upright models with one exception this excep tion is referrred to The 1927 Duo Art Service Manual and will be discussed later The adjustment of the various degrees of shad ing in the Duo Art must be approached from a musical standpoint if effective results are to be achieved Assuming of course that mechanical conditions are equal it is possible through the unique dynamic control to control the entire register of the instrument
46. ned admitting atmosphere to pouches under primary valves 5 raising them and putting secondary valves 11 amp 12 under suction causing them to drop and making a passage for air to channel 13 where it follows to passage 15 into theme regulator 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 intochamber 8 from player action and theme valve 12 being closed passes through flap valve 10 into chamber 7 through channel 14 into accompaniment reg ulator through knife vaive 16 and to the pump THEME CONTROL OF BASS Air 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 tt should be understood that the air once in cham ber 7 cannot return to chambers 6 amp 8 A study of the flap valves 9 amp 10 will be self explanatory MANUAL CONTROL Other remarkagle features of the Duo Art Pianola Piano are the devices for its manual control 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 tn the spool box The first leve
47. o 4 8 ins No 8 It will be noted that the note holes start at the fourth hole from the bass end and the fourth hole from the treble end reading from the outer edge toward the middle the first speaking note is No 5 and the last is No 84 making eighty speaking notes This applies to the later type Duo Art mechanisms In the earlier models the speaking scale is full eighty eight notes on straight eight eight note rolls but still remains eighty speaking notes on the Duo Art reproduction Note holes 1 2 3 and 4 at the bass end and 85 86 87 and 88 at the treble end have each directly above them a perpendicular oblong port These oblong ports are the accordion dyna mic control ports and are connected by tubing to the Duo Art cut out pouch blocks directly behind the spool box These blocks contain a series of four pouches on either side of the blocks one on the bass end and the other on the treble end and are connected to the supply from the Duo Art cut out block on the left hand end of the spool box they marked Duo Art On and Duo Art Off With the Duo Art lever at the On position atmosphere is admitted to the top side of the note pouches on the blocks marked 1 2 3 4 notes and 85 86 87 88 notes this inflates the pouches cuts off the note holes from the tracker bar With the Duo Art switch at the position atmosphere is admit ted through any one of the accordion
48. ool box Loosen up screws No 2 and 3 on tracker triggers and push away from music roll Hold tracker pneumatics at center and note if right hand music spool carrier is at cen ter of shifting cam No 8 as shown in diagram if not adjust turnbuckle No 1 Turn on electric current and set tempo at 70 then adjust set screw No 4 so that holes in music or test roll align with holes in tracker bar Next adjust tracker triggers No 5 and No 6 so that they almost touch edge of music roll then tighten screws No 2 and No 3 It is advisable to play a few music rolls to make sure that tracker adjustments average up correctly By keeping a very loose take up spool brake and a slow speed on reroll the edges on the music roll will be materially preserved UPRIGHT DUO ART GOVERNOR C5 MSW Illustration 2 UPRIGHT DUO ART GOVERNOR AG IQg WWW if KIETEN m F Refer to Illustration M The purpose of the Governor is to assure an even speed to the music regardless of the tempo in which it is played All pneumatic player actions have a device of similar purpose The Duo Art Governor is very simple in design and sturdy in construction The enters the Governor from the wind motor at channel No 6 and passes down channel No 3 providing the tempo port is open to point ten or more The air then passes to the knife valve port No 5 and out channel No 8 to th
49. ore 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 fost 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 SPOOL BOX GEARING AND CONNECTIONS Step 1 See that the gearing is properly oiled and all set screws tightened Set the and play brakes See that the sprocket chains are not too loose nor tight Have ail parts on wind motor free but not noisy Use no oil on the wind motor Pump out tracker bar and insert test rol_in spool box ke ELECTRIC MOTOR PUMP AND FONNEGTIONS 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 wil
50. r 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 fevers on the key front next to the right one above the other there is no noticeable result As will be noticed the dia gram the theme modulating fever 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 amp 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 port leading to the pump The more this port is opened the louder the playing The fifth controi is the Duo Art lever in the spool box This lever should be the Duo Art position for all Duo Art rolls to be played automatically To play Duo Art rolls with persona expression have this lever in the central position For all other 88 note rolls have this lever at OFF When the Duo Art lever
51. raised and the air passes to the knife valve port No 17 where the pressure is cut down or softened From channel No 17 the air passes to chamber No 7 then down No 6 up No 2 and out No 1 to the pump The spring No 20 controls the degree of modulation which should be one half the full volume of the Duo Art If the spring No 20 is set so the degree of modulation is one half the full volume of the Duo Art it will be found that there is enough spring tension to operate the loud pedal pneumatic and the Accompaniment and Theme Accordion pneumatics so they will work fast enough and still remain quiet in their operation With the Dynamic Lever at Concert position the modulator pneumatic has no effect upon the volume of the Duo Art The action cutout valve No 5 closes reroll and pneumatic No 14 which operates slide covering channel No 3 collapses which lets in the outside air and eliminates any excessive load on the electric motor The loud pedal is supplied from port No 18 The Duo Art continued CRASH DEVICE GRAND EXPRESSION BOX Refer to Illustration R The Grand Duo Art Expression Box is constructed differently from the upright box due to the differ ence in design of the two instruments but the basic principles are the same in both expression boxes The grand expression box has a crash valve which functions when power No 15 on the Theme side appears in the music roll No I in illustratio
52. ration on page 35 of the Duo Art 1927 Service manual will show that the atmosphere from the wind motor enters the governor at channel No 6 passes through channel No 3 provided the tempo port is open to ten or more through knife valve port No 5 and out through channel No 8 to the pump Spring No 9 is the opposing suction in the governor pneumatic Figure No 3 is the tempoport No 2 is the tempo control slide valve No 4 is the reroll port and No 7 is the reroll slide valve Figure No 1 is a bleed channel connecting with the out side air Its function is to prevent the wind motor from creeping when the tempois at but this channel is cut off when the tempo is advanced three or four points Adjustment of the governor will be taken up later under the caption Testing In the grand Duo Art the governor is practically the same except that the action cut out is in the modulator box underneath the bed next to the rotary pump and its function will be discussed under the head ing Grand Modulator Pneumatic Sustaining and Hammer Rail Lift The entire layout of the tubing and con trol of the sustaining pedal and the hammer rail lift will be found in illustration on page 37 There are three valves in the sustaining pedal valve chamber and two in the hammer rail valve chamber Those who are familiar with the Duo Art since its in ception will readily see the advantage of this
53. set tight after the adjustment of the cam has been made The Duo Art continued When the tracker pneumatics have been centered and other adjustments made so that the note holes in the music roll align with those in the tracker bar the tracker ears should be set These ears should be so ad justed that they just touch the edges of the paper and the screws figures 2 and 3 should be tight Under no condition should the tracker ears be bent into position with a pair of pliers or anything else This would not on ly be bad practice and show a lack of knowl edge on the part of the service man but there would be danger of damaging the ears to such an extent that they might have to be replaced with a new set Many music rolls have been ruined through faulty and in correct setting of the tracker ears and the blame placed on the tracking device Editor The section on the Duo Art tracking device was printed in February 1929 The 1929 model of the Duo Art did not have ears protruding from the tracker bar This was replaced by holes in each end of the tracker bar For adjusting the tracking on either model make sure the width of the roll you are using is exactly 11 inches wide After tracking adjustments are com pleted check that the perforations on the roll center directly over the holes in the tracker bar The Duo Art Upright Governor The Duo Art governor is extremely sensitive and positive in operation Reference to illust
54. t pedals in the upright Duo Art and spring No 20 in illustration page 41 controls the speed of the loud pedal in the grands On uprights soft pedal should move ham mers up to one inch from strings On grands soft rail should raise 5 inch from normal position The Duo Art continued REROLL REPEAT AND SWITCH CUTOUT DEVICES Illustration REPEAT SLIDE BLOCK REROLL PORT SLEEVE BEARING REPEAT SLIDE BLOCK OFF REWIND LEVER REROLL Illustration The reroll mechanism is controlled by the first hole in the bass end of the tracker bar and is tubed up direct to the reroll valva the rewind and repeat valve box It controls the reroll pneumatic No 10 which throws the spool box gearing into reverse and operates the cutout valve to top action REPEAT AND SWITCH CUTOUT The repeat mechanism is controlled by the hole in the left end of takeup spool No 7 this hole is bored to center of spool and then proceeds to the left through a tubular bearing which supports spool and on to the Repeat block No 1 which if in the On position allows the atmosphere to go through tube No 4 and down tube No 3 to the valve oper ating Repeat pneumatic 11 This pneumatic throws the spool box gearing into Normal position and repeats playing of music An examination of Repeat block No 1 shows that when it is placed Repeat O
55. the right hand side of the case and shows the The Duo Art continued pneumatic and the valve box as a unit In the grand model the switch unit and the switch pneumatic are separate units The principle remains the same no matter how the units are assembled Grand Duo Art Modulator Control Pneumatic The modulator control box illustration 41 is shown only in the grand model and only in instruments of late manu facture Its function is to modify or soft en the normal Duo Art without affecting any of its dynamic gradations It also con trols and regulates the supply of atmos phere to the accordion dynamics and the sustaining pedal and contains the cut off valve which cuts off the top action on reroll A pallet valve block is situated underneath the key bed at the front left hand end of the case and is connected with levers marked Concert or Normal Soft or Dance This pallet valve block is known as the dyna mic valve block and is made up of two pallet valves with four nipples on the later types and three on the older types When the dynamic lever is at the Soft position the pallet is opened and the atmosphere is admitted to the valves of the hammer rail and No 2 accordion pneumatic on the accompaniment side Through another nip ple atmosphere is also admitted to valve No 10 which raises and forces the air entering chamber No 13 to pass through the knife valve port No 17
56. tion and are marked 1 T 2 T 4 T 8 T They control the Theme in conjunction with the holes in the tracker bar marked Theme and T Theme CHART SHOWING DYNAMIC GRADATIONS 10 It will be noticed that each number in the Dynamic Gradation control is double its predecessor and that is exactly what they are in their dynamic power From the tracker bar these dynamic control tubes lead through two cut off pouch blocks From these pouch blocks the tubes lead to the dynamic valve box No 36 These tubes control the accordion pneu matics and each of these accordion dynamics has four small pneumatics each set to collapse a certain distance by small adjusting screws These pneu matics can work separately or in combination to re produce every gradation of piano expression ACCORDION DYNAMIC CONTROL OF THE KNIFE VALVE SHOWING SIMPLICITY OF DUO ART EXPRESSION CONTROL Illustration G ACCORDIAN PNEUMATICS Key Chart 1 Manual Control Lever 2 Exhaust from Top Action 3 Knife Valve Tension Spring 4 Accordion Pneumatic and Knife Valve Connect ing Rod 5 Knife Valve Valve and Regulator Pneumatic Connecting od 7 Regulator Pneumatic 8 Regulator Pneumatic Coil Spring The Duo Art continued TRACKING DEVICE Illustration L 72 TRACKING DEVICE ADJUSTMENT Refer to Illustration L Insert a test roll or music roll measuring 114 inches in width in the sp
57. tom cups causing the secondary valves to drop and thus momentarily open a channel between the pneumatic stack and theme regulator The opening of this channel is the action whereby the air from the pneumatic stack is changed from the accompaniment regulator to the theme regulator The moment one or both of the theme secondary valves drop since the theme regulator suction is usually of a higher intensity than that of the accompaniment regulator this stronger suction will draw the flap valves 21 and 23 to their seats and cut off channel 22 from the pneumatic stack Thus momentar ily the stack may be entirely cut off from the accompaniment regulator This occurs only when the stack is opened to the theme regula tor When this occurs the air from the stack entering chambers 20 and 24 will pass down and over the theme secondary valves and into the channel underneath and directly behind the accompaniment channel this channel is shown but is not numbered on the phantom view but is indicated by the arrows from the theme secondaries through the port shown leading into the theme regulator and there to the pump and exhaust This condition can happen collectively or singly as the case may be according to the perforations on the music roll The strength of the blow is governed by the movement of the knife valve within each of the regulators This The Duo Art continued movement is controlled by the collapse of the accordio
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