Patent GB-1049524-A (GB)
Title: Improvements in musical instruments
IPC: G10H3/09
Filed: 1962-05-11
Abstract: 1,049,524. Electrophonic musical instruments; selective tape apparatus. J. M. HARVEY, and W. I. FRANSEN. May 10, 1963 [May 11 1962], No. 18269/62. Headings G5J and G5R' In a keyboard type musical instrument in which actuation of the keys initiates relative movement between a play-back transducer and a magnetic recording medium carrying, on tracks of finite length, recordings of musical tones, rhythmic, percussion or other special sound effects, release of the keys is arranged to produce relative movement to return the recording medium and transducers to a prescribed relative position. By this means it is assured that playback always commences at a position on the recording carrying the beginning of any rhythmical pattern or the initial " attack " of musical tones. The invention is described in connection with an instrument having a righthand keyboard 10 (Fig. 1, not shown) controlling the play-back of pre-recorded tones of single orchestral instruments or of organ stops and a left-hand keyboard 12 for pre-recorded rhythmic and other sound effects. For each key 14, Fig. 2 (also Figs. 3 and 4, not shown) there is provided a length of magnetic tape 16 carrying, in each of six finite length sections, three parallel tracks comprising recordings of different toned &c. effects in a pitch appropriate to the particular key. Each tape is tensioned between parallel rollers 18, 20 in a path including an idler roller 26 and a double pulley 22 loaded by a tension spring 24. Play-back heads 40 are positioned below each tape and when a key is depressed an idler roller 36 carried by the key pushes the tape into engagement with a rotating capstan 30 driven by motor 32 and sprocket 34 and common to all keys whilst felt'pressure pads 38 also carried by the key press the tape into engagement with the heads. When the tape moves a bight of slack is formed in a receptacle 42 and the "festoon" 28 contracts against spring 24 (Fig. 2-key undepressed and Fig. 3- key depressed) until the key is released and spring 24 returns the tape to its initial position. The latter position must be one in which the commencement of a selected one of the six discrete lengths of the tape coincides with the play-back heads 40 and such positioning is determined by the tensioning rollers 18, 20, which, when a particular tape length (" Stop ") is selected by means of push-button (" STOP control") switches 78-83, Fig. 1, are driven by motor 68 to position the tape accordingly. The motor is controlled by a photo-electric system 76 (also Fig. 6, not shown) in accordance with opaque marks 72 (see Fig. 4) on a translucent tape 70 driven by the rollers 18, 20, the switches 78-83 operating to condition photo-sensitive devices to respond to selected marks in accordance with the required tape position. The play-back heads 40 are carried by a channel-section member 46 (Fig. 5, not shown) having a length equal to the full width of the keyboard and mounted on rollers 62 running on a similar channel-section member 60 for movement against the (light) tension of either of springs 65, 66. This movement (for keyboard 10) is effected by push-button plungers 48 which, when depressed, operate via the link mechanism shown to move the heads transversely of the tape 16 by a distance equal to half the spacing of the record tracks so that the three tracks may be selected separately or a combination of two adjacently recorded tracks may be selected. In the case of key-board 12 only three pushbutton plungers 50 are provided since only one rhythm or percussion &c. effect is required at any one time. To prevent damage to the mechanism a pivoted bar 104 mounted under the keys 14 operates as a key-lock when the tape positioning mechanism is operating as a result of selection of one of the press-button switches 78-83. The tape speed (when playing the instrument) is 19 cms./sec. and it is stated to be adequate to provide sufficient tape length in the " festoons " 28 for eight seconds of continuous playing of any tone or sound effect. The signal output from the play-back heads is fed to a conventional amplifier and loud-speaker equipment. " Swell " pedals 114, 115 and a volume control knob 116, 117 are provided for the respective keyboards together with a minimum volume setting knob 118 and a reverberation control 119 for keyboard 10. Controls for the introduction and cancellation of vibrate effects may take conventional forms. The speed of the capstan motor 32 may be adjusted by control knob 120.