The explanation of the terms listed below refer to their usage in the field of Mechanical Music. Many of the descriptions are from the book The Golden Age of Automatic Musical Instruments by MBSI member Arthur A. Reblitz, published by the Mechanical Music Press, Woodsville, New Hampshire; copyright 2001. They are used here with permission of the author and publisher. Permission is granted for writers to use a limited number of brief excerpts provided credit is given to the MBSI web site, the title of the original work and the author. Written permission is required for all other uses. German nouns and words that are also names of places are capitalized.

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Drehorgel: German term for a hand-cranked barrel organ. * From the German drehen, (to turn).

damper: 1. In a piano, a felt pad which mutes the string after it has been sounded and the piano key is then released. Also controlled by the sustaining pedal; when the sustaining pedal is "on," the dampers are lifted and the notes continue to sound. 2. Any device which mutes or dampens the sound of a percussion instrument. Dampers are used on bells, drums, and certain other effects in large orchestrions and organs. 3. The fine quill or wire mounted under the tip of a cylinder music box tooth, or mechanical device in a disc box, for the same purpose.

damper pin: The tapered, brass or steel brad that holds the damper in place in the anvil under the tooth of a cylinder musical box.

dance organ: Self-contained player pipe organ, usually with an ornate facade, used in dance halls, cafés and other locations, especially in Belgium and Holland. Softly voiced (in comparison to band organs). Distinguished by the strongly accented rhythm of their music; the short and powerful chords of the accompaniment pipes maintain the dance rhythm. Usually of large size (8' to 20' or more in width) and fitted with a key frame system for playing cardboard music books, or a tracker bar for playing paper rolls. Later models (after about 1930) have novelty percussion, accordions, and other instruments prominently displayed on the facades. Made by Bursens, Decap, Mortier, and others. Some later models use electronic tone generators instead of organ pipes. * Synonym for small dance organ: café organ.

declanche: See cancel.

decrescendo: To become softer gradually. Opposite of crescendo.

detent: A device for holding a moveable member fixed in one of two or more desired positions; allowing for manual selection of the position. Example: allowing a mechanism to start or stop.

diapason pipe: The basic tone of the church pipe organ; smooth, steady sounding pipes richer in tone than flutes but not as raspy as strings nor as bright as brilliant reed pipes.

diminuendo: (often seen abbreviated as dim.) Same as decrescendo (also listed in this Glossary).

disc: Circular sheet of metal (for use on most types of disc music boxes), cardboard (for use on certain organettes), or composition cardboard-metal (for certain organettes) on which a musical program is arranged in the form of perforations or projections extending from the underside. Almost always easily changed, so that different tunes can be played on the same instrument. * Also spelled disk. * Synonyms (not in popular usage with collectors today, however): record, tune sheet.

disc music box: Music box on which a disc causes a music comb to be plucked by means of intervening star wheels (usually) or levers. One of two main music box types (the other: the cylinder music box). Popular during the 1890s and early 1900s. Made by Polyphon, Regina, Symphonion, and others.

disc shifting musical box: A musical box designed to play two tunes in two revolutions of the disc by means of laterally shifting the disc between tunes. The New Century and Sirion boxes are the best known of this type.

division: In a band organ or dance organ, a group of ranks of pipes devoted to a specific musical part: bass, accompaniment, melody, countermelody, etc. In a pipe organ, a group of ranks usually associated with a certain manual or manuals.

doppel: German term for double; hence Doppelflöte (a double-mouthed flute pipe), Doppelmechanik (double mechanism), etc.

doppel flute pipe: Stopped flute pipe, with two mouths oriented on opposite sides of the pipe, which produces a loud clear tone without being too shrill. A popular rank in many Wurlitzer BX and CX orchestrions. The smaller scale rank pitched an octave higher and used as a piccolo in large Popper orchestrions has a very loud, penetrating tone. * German: doppelflöte.

double combs: In a disc music box, separate combs played by separate star wheels. (In contrast to duplex combs, also listed in this Glossary.)

dowels: . Set-pins that enable a component part to be removed and replaced in the exact same position.

draaiorgel: Dutch term for a hand-cranked organ, usually of the barrel or cardboard music type.

drawing board arrangement: Music roll arrangement that is created on a special drawing board equipped with a roll of paper and scale sticks for the note placement and length. Certain early drawing board arrangements, such as some of those by Wurlitzer's arrangers who were paid by the foot of paper churned out, are very mechanical and repetitious sounding. Others, such as Gustav Bruder's superb Weber Maesto rolls, are remarkably lifelike and exciting.

drive gear pinion: The gear which is driven by the spring barrel and delivers the spring tension to the cylinder arbor.

dulciana: A soft diapason-like pipe organ stop.

duplex comb(s): In a disc music box, two identical combs that are played by the same set of star wheels, in which two points on one star wheel pluck the teeth on two combs at once. (In contrast to double combs, also listed in this Glossary.)

duplex roll mechanism: Roll frame or spoolbox assembly in an electric piano, photoplayer, or orchestrion which accommodates two rolls, so that one roll can play while the other is rewinding or at rest. Made by Hupfeld, Seeburg (for photoplayers), Wurlitzer (photoplayers and band organs), and others. Also, duplex roll changer: two revolver mechanisms or automatic roll changers (also listed in this Glossary) arranged side by side, with several rolls on each changer mechanism. These were made by Hupfeld and Philipps.