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1<?php
2        $seiten_id = 'pianola-funktionserklaerung';
3        $version = '$Id';
4        $titel = 'Functional explanation of the pianola';
5       
6        require '../../lib/technikum29.php';
7?>
8<h2>Functional explanation of the pianola</h2>
9
10<div class="desc-right auto-bildbreite borderless no-copyright" title="Zum Vergrößern klicken">
11   <a class="popup" href="/de/geraete/pianola-funktionserklaerung/fotos/pianola-offen.jpg"><img src="/de/geraete/pianola-funktionserklaerung/fotos/thumb.pianola-offen.jpg" alt="Inside view of the pianola" width="300" height="225"></a>
12   <p>Inside view of the pianola</p>
13</div>
14   
15<p>The "pianola" is an automatic piano - the instrument shown in the picture on
16the right was built in 1915. Instruments of this type are controlled by a
17vacuum system that is powered by bellows operated either manually or by means
18of a motor. The pneumatic system of the instrument described in the following
19is powered by a motor.</p>
20
21
22<div class="desc-left auto-bildbreite borderless no-copyright" title="Zum Vergrößern klicken">
23   <a class="popup" href="/de/geraete/pianola-funktionserklaerung/fotos/abfuehlkamm.jpg"><img src="/de/geraete/pianola-funktionserklaerung/fotos/thumb.abfuehlkamm.jpg" alt="Touch sliding block" width="268" height="109"></a>
24   <p>Touch sliding block</p>
25</div>
26
27<div class="desc-left auto-bildbreite borderless no-copyright" title="Zum Vergrößern klicken" style="clear: left;">
28   <a class="popup" href="/de/geraete/pianola-funktionserklaerung/fotos/notenrolle.jpg"><img src="/de/geraete/pianola-funktionserklaerung/fotos/thumb.notenrolle.jpg" alt="music roll" width="268" height="175"></a>
29   <p>Music roll</p>
30
31</div>
32<!--<div class="left-thumb" style="width: 260px;">
33   <img src="/de/geraete/pianola-funktionserklaerung/zoomgrafiken/rolle.png" alt="Rolle schematisch">
34   <p>Die ablaufende Rolle und die Abtastung rein schematisch</p>
35</div>-->
36The piano roll is a strip of paper, many meters long, with holes punched in
37rows. Single holes or sequences of holes represent notes. This paper strip
38moves over a pickup bar with 88 openings (one for each key of the piano). In
39addition to these, this pickup contains additional openings which are used to
40control the pedals, the attack and the like.
41
42
43</p>
44<div class="desc-right auto-bildbreite borderless no-copyright" title="Zum Vergrößern klicken">
45   <a class="popup" href="/de/geraete/pianola-funktionserklaerung/fotos/pianola-innen.jpg"><img src="/de/geraete/pianola-funktionserklaerung/fotos/thumb.pianola-innen.jpg" alt="Back view of the pianola" width="300" height="225"></a>
46   <p>Back view of the pianola</p>
47</div>
48<p>Clearly visible in the picture of the right are the yellow colored lead tubes
49that connect the pickup bar with the pneumatic amplifiers. These amplifiers are
50called "relays" and amplify the tiny differential pressures delivered by the
51pickup mechanism sufficiently to actuate the keys and pedals of the piano.</p>
52
53
54<div class="box center" title="Zum Vergrößern klicken">
55   <a href="/de/geraete/pianola-funktionserklaerung/zoomgrafiken/schema-uebersicht.png"><img style="border: none;" src="/de/geraete/pianola-funktionserklaerung/zoomgrafiken/thumb.schema-uebersicht.png" alt="Schematic diagram of a single amplifier/actuator
56(relay) element"></a>
57   <p class="center"> Schematic diagram of a single amplifier/actuator
58(relay) element
59   (<a href="/de/geraete/pianola-funktionserklaerung/zoomgrafiken/schema-uebersicht.png">größeres Bild</a>)</p>
60</div>
61
62
63<!--
64    Befehle zum Generieren der Thumbnails:
65
66    $ for bild in *.png; do convert -verbose $bild -resize 200x150\> -size 200x150 xc:white +swap -gravity center -composite thumb.$bild; done;
67-->
68
69<h3 class="clear"><a href="/de/geraete/pianola-funktionserklaerung/einzelbilder/Bild1.png">Picture 1</a>: Quiescent state</h3>
70<div class="box left">
71    <a class="thumb" href="/de/geraete/pianola-funktionserklaerung/einzelbilder/Bild1.png"><img src="/de/geraete/pianola-funktionserklaerung/einzelbilder/thumb.Bild1.png" alt="Amplifier/actuator in quiescent state"></a>
72</div>
73
74<p>The schematic diagram shows one relay element. 88 of these are necessary to
75control all of the piano's keys. Due to their size, these 88 relays are mounted
76in three rows. Yellow color denotes part of the vacuum system while blue marked
77areas are at atmospheric pressure. </p>
78
79<h3 class="clear"><a href="/de/geraete/pianola-funktionserklaerung/einzelbilder/Bild2.png">Picture 2</a>: Hole in the piano roll, air enters the pickup bar</h3>
80<div class="box left">
81    <a href="/de/geraete/pianola-funktionserklaerung/einzelbilder/Bild2.png"><img src="/de/geraete/pianola-funktionserklaerung/einzelbilder/thumb.Bild2.png" alt="Schema des pneumatischen Systems während Luft einströmt"></a>
82</div><div class="box right">
83    <a href="/de/geraete/pianola-funktionserklaerung/einzelbilder/Bild2.png"><img src="/de/geraete/pianola-funktionserklaerung/einzelbilder/big.Bild2.png" alt="Ausschnitt aus dem Schema des pneumatischen Systems, während Luft einströmt"></a>
84</div>
85
86    <p>A hole in the piano roll allows air to enter the corresponding hole in the
87pickup bar. A small "pillow" located under the right valve of the relay is
88inflated by this stream of air which in turn opens the valve.
89</p>
90
91
92<h3 class="clear"><a href="/de/geraete/pianola-funktionserklaerung/einzelbilder/Bild3.png">Picture 3</a>: Amplification:</h3>
93<div class="box left">
94    <a href="/de/geraete/pianola-funktionserklaerung/einzelbilder/Bild3.png"><img src="/de/geraete/pianola-funktionserklaerung/einzelbilder/thumb.Bild3.png" alt="Schema des pneumatischen Systems, erster Kolben bewegt sich"></a>
95</div><div class="box right">
96    <a href="/de/geraete/pianola-funktionserklaerung/einzelbilder/Bild3.png"><img src="/de/geraete/pianola-funktionserklaerung/einzelbilder/big.Bild3.png" alt="Vergrößerung des Verstärkungseffekts durch den Kolben"></a>
97</div>
98
99<p>This right valve allows air to enter the left part of the relay which is built
100in a similar way. Another "pillow" actuates the left valve which is much bigger
101than the left valve and thus allows more air to flow. These two valves in fact
102act like an amplifier: The small pressure difference sensed by the pickup bar
103controls the first (right) valve which acts as a first amplifier stage. This
104controls the second (left) valve which acts as a power amplifier operating the
105the bellow shown below the relay unit.</p>
106
107<h3 class="clear"><a href="/de/geraete/pianola-funktionserklaerung/einzelbilder/Bild4.png">Picture 4</a>: Contracting the bellow</h3>
108<div class="box left">
109    <a href="/de/geraete/pianola-funktionserklaerung/einzelbilder/Bild4.png"><img src="/de/geraete/pianola-funktionserklaerung/einzelbilder/thumb.Bild4.png" alt="Schema des pneumatischen Systems: Der zweite Kolben sorgt für eine weitere Verstärkung des Effektes"></a>
110</div><div class="box right">
111    <a href="/de/geraete/pianola-funktionserklaerung/einzelbilder/Bild4.png"><img src="/de/geraete/pianola-funktionserklaerung/einzelbilder/big.Bild4.png" alt="Ausschnitt aus dem Schema in der jetzigen Position"></a>
112</div>
113
114<p>The left valve of the relay connects the bellow located under the relay block
115with the evacuated part of the pneumatic system. When activated, this valve
116will cause the bellow to contract which in turn moves the corresponding key of
117the piano.</p>
118
119
120<h3 class="clear"><a href="/de/geraete/pianola-funktionserklaerung/einzelbilder/Bild5.png">Picture 5</a>: Preview of a tone</h3>
121<div class="box left">
122    <a href="/de/geraete/pianola-funktionserklaerung/einzelbilder/Bild5.png"><img src="/de/geraete/pianola-funktionserklaerung/einzelbilder/thumb.Bild5.png" alt="Schema des pneumatischen Systems: die Luft strömt aus dem Blasebalg, er zieht sich zusammen"></a>
123</div><div class="box right">
124    <a href="/de/geraete/pianola-funktionserklaerung/einzelbilder/Bild5.png"><img src="/de/geraete/pianola-funktionserklaerung/einzelbilder/big.Bild5.png" alt="Vergrößerung der Bewegung des Blasebalges"></a>
125</div>
126<p>Without additional hardware, the bellow would stay in the contracted state
127after being actuated once. Thus, some means are necessary to release the bellow
128after a note and ready the system to play the next note. If there is no hole in
129the piano roll following the hole which actuated the bellow, the bellow must be
130returned to its inflated state as quickly as possible. </p>
131
132
133<p>The picture on the right shows a small connection between the tube coming from
134the pickup strip and the vacuum system on the far right. This connection has a
135very small diameter so that it does not negatively affect the inrushing air
136current from the pickup bar when a hole is detected. If there is no hole, this
137connection withdraws the remaining air at atmospheric pressure from the right
138valve system thus closing this valve which, in turn, will close the second
139valve, which will eventually cause the bellow to inflate again. Now the
140pianola is ready to play the next note. </p>
141
142<div class="right">
143        <img src="/de/geraete/pianola-funktionserklaerung/entlueftung.png" alt="Die Entlüftungskammer">
144</div>
145
146<p>The pianola is able to play pieces which were impossible to play for a human
147player. Accordingly, there are pieces composed for the pianolo exclusively
148(like the "Studies for Player Piano" by Conlon Nancarrow).
149
150It is impressive to see what can be done by more or less simple mechanical
151systems.
152
153
154
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