Apparatus For Reproducing Musical Notes From An Encoded Record

Abstract

Apparatus for reproducing music, either by playing or by printing a musical score. The music is recorded on a record medium, such as magnetic tape, which has at least one and no more than eight recording channels or tracks. Representations of the fundamentals of the individual notes of the music are recorded on the record medium without inclusion of representations of the harmonics of these notes. The reproducing apparatus, according to the invention, includes the combination of means for reading the representations of the fundamentals, means for decoding these representations and means for receiving the decoded representations and reproducing the musical notes.

Parent Case Text

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of the application, Ser. No. 756,857, filed Sept. 3, 1968, by Karl F. Milde, Jr.

This application is also related to the application, Ser. No. 79,046, filed concurrently with this application by Karl F. Milde, Jr. entitled "Method and Apparatus for Recording Music".

Description

BACKGROUND OF THE INVENTION

The present invention relates to apparatus for reproducing music from a record medium, such as a magnetic tape or a phonograph disc, which may be read by conventional sound reproducing equipment.

More particularly, the present invention relates to apparatus for reproducing music from a record medium having at least one and no more than eight recording channels or tracks and having recorded on these channels encoded representations of the fundamentals of the individual notes of the music without inclusion of representations of the harmonics of these notes. Such a record, and a method and apparatus for producing such a record, is described in the two related applications referred to above.

There are a number of different techniques of recording music known in the art. For example, music has been recorded on paper with ink as a conventional "score", or with holes in a form which is suitable for machine reading. The recordings of the former type are the recordings most frequently read by musicians, while those of the latter type have been used in the familiar "player piano".

Music has also been recorded on magnetic and mechanical records in a variety of ways. Most often used is the simple "analog" recording; the signal that is recorded corresponds in frequency and intensity to the acoustical vibrations of which the music is formed. Music has been recorded on magnetic tape in digital form by converting an analog signal representing the music to a pulse modulated signal before writing it on the tape.

So far as is known, however, none of the prior art techniques of magnetic or mechanical recording have employed the type of "writing" that makes recordings on paper possible. In particular, none of the techniques of magnetic recording utilize the fact that music is "structured" sound and can be described by information giving the duration, the pitch, the level and the quality of its individual notes.

Since most home entertainment systems include either a magnetic tape playback deck or a phonograph record turntable or both, it would be convenient to record the duration, pitch, level and quality of musical notes on a magnetic or mechanical recording for playback in the home. Such a recording would permit already existing playback equipment to be used as an input device for a player piano, a player organ or even an on-line printer for printing a musical score.

However, unlike the paper roll recordings which have previously been universally employed to operate player pianos, both magnetic tape and phonograph recordings have a limited number of available recording channels. Magnetic tape is normally divided into two, four and at most, eight tracks while phonograph discs have a maximum of two channels per spiral groove. As a result, it is necessary if music is to be recorded on these limited channel record media, to encode the musical information to "squeeze" it into the available space.

Two techniques for encoding representations of musical notes are disclosed in the above-mentioned copending application, Ser. No. 79,046. This copending application describes a record, and a method and apparatus for producing such a record, which has recorded, on a limited number of channels thereon, encoded representations of the fundamentals of the individual notes without inclusion of representations of the harmonics as well as representations of the level and/or quality of these notes.

SUMMARY OF THE INVENTION

It is a general object of the present invention, therefor, to combine the mechanical readability which is associated with a musical paper roll recording with the advantages of magnetic tape and mechanical phonograph recordings; namely, the ability to accurately record a large quantity of information for playback by inexpensive and readily available equipment.

It is a more particular object of the present invention to provide apparatus which utilizes conventional equipment for reading encoded musical information from a magnetic tape or mechanical phonograph recording in a system for operating a player piano, a player organ or an on-line printer for printing a musical score.

These objects, as well as other objects which will become apparent in the discussion that follows, are achieved, according to the present invention, by providing apparatus for reproducing music from a record medium having recorded, on a maximum of eight recording channels thereon, encoded representations of the fundamentals of the individual notes of the music without inclusion of representations of the harmonics of these notes. This apparatus may comprise a conventional reading device, such as a read "head" in the case of a magnetic tape recording or a phonograph "pickup" in the case of a mechanical recording, for reading the representations of the fundamentals of the musical notes from the record medium; a relatively simple electronic device, the construction of which will depend upon the manner in which the representations of the fundamentals are encoded, for decoding the fundamentals of the musical notes; and a device, such as a player piano, player organ or on-line printer, for reproducing the musical notes.

It will be appreciated that, of the three elements of the apparatus just described, the record medium reading device and the music reproducing device are well-known elements which are readily available commercially. Only the decoding device and the apparatus combining the decoding device with the reading and reproducing devices is "new" and must be described in detail herein.

As mentioned above, the particular construction of the decoding device will depend upon the manner in which the representations of the fundamental of the musical notes are encoded. In the copending application, Ser. No. 79,046 referred to above, two different systems of encoding are described as preferred embodiments. The first system of encoding is referred to in that application as "serial encoding" while the second system of encoding is referred to as "frequency encoding".

With serial encoding the instantaneous existence and pitch of each of a plurality of notes of the well-tempered scale is rapidly and repeatedly scanned and the information obtained from the scan is recorded on the record medium on a single channel. With frequency encoding the instantaneous existence and pitch of each of a plurality of notes of the well-tempered scale is recorded on one or more channels of the record medium at a different frequency.

In the case where the representations of the musical notes are encoded in serial form, the decoding device may simply include a plurality of flip-flops, one for each note of the well-tempered scale, for periodically storing the fundamentals read by the reading device, and a plurality of gates, one for each flip-flop, for gating to a like number of output terminals the existence of each fundamental stored in the flip-flops.

Where the representations of the fundamentals are encoded in frequency form, the decoding device may simply include a plurality of filters, arranged to pass each separate recording frequency to a separate output terminal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the general plan of the apparatus, according to the present invention, for reproducing music recorded in encoded form on magnetic tape.

FIG. 2 is a detailed schematic diagram of a first preferred embodiment of the decoding device shown in block form in FIG. 1.

FIG. 3 is a detailed schematic diagram of a second preferred embodiment of the decoding device shown in block form in FIG. 1.

FIG. 4 is a schematic diagram of apparatus, shown in block form in FIG. 1, for printing a musical score.

FIG. 5 is a schematic diagram of apparatus, shown in block form in FIG. 1, for playing music on a "player piano".

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, FIG. 1 illustrates the general plan of the apparatus according to the present invention for reproducing music recorded in encoded form on a limited number of channels of a record medium, in this case a magnetic tape 1.

The apparatus includes read heads 2 and 3 arranged to read each recorded track of the magnetic tape 1. These heads are connected to a device 4 which decodes the musical pitch, quality and level information read from the tape by the heads 2 and 3. The decoder device is connected via a switch 5 to apparatus 7, such as an electronic organ or a player piano, for playing the musical composition read from the tape 1. The decoder device is also connected via a switch 6 to apparatus 8 for printing the score of the musical composition read from the magnetic tape. The switches 5 and 6 are operative to connect or disconnect the decoding device from the player 7 or printer 8, respectively. The musical composition read from the magnetic tape may therefore be reproduced by playing, or printing, or both playing and printing the musical score.

FIG. 2 schematically illustrates the preferred embodiment of apparatus which decodes a musical composition recorded on a magnetic tape 9 in frequency form in the manner described in the above-mentioned copending application, Ser. No. 79,046. This decoding apparatus operates to one or selectively pass the various encoding frequencies.

As described in the application, Ser. No. 79,046 the existence of each note of at least a portion of the well-tempered scale is recorded on track of the magnetic tape as a signal of a particular unique frequency. If desired, information regarding the quality of the music, such as the presence or absence of one or more organ stops or the operation of one r more piano pedals, may likewise be recorded on the magnetic tape as the presence or absence of further signals of different frequencies.

The level or loudness of the notes of the musical composition may be recorded either in digital or analog form. If the level is to be digitalized-- that is, divided into a plurality of discrete levels-- it may be recorded as the presence or absence of a signal of a particular one of a number of discrete frequencies. If the level is to be recorded in analog form it may be recorded as the amplitude of a single at a separate single frequency, or as the amplitude of the signals of various frequency representing the existence of notes of particular pitch.

The magnetic tape 9 shown in FIG. 2 is illustrated as a three-track record read by the three heads 10, 11 and 12. The heads 10 and 12 are arranged to read tracks containing an encoded record ("E.R.") while the head 11 is arranged to read a track containing a conventional recording ("C.R."), The encoded record contains the information required to operate a player organ or piano while the conventional record may contain, for example, voice or instrumental music for reproduction by a conventional loudspeaker simultaneously with the operation of the organ or piano.

The read heads 10, 11 and 12 are connected to preamplifiers 13, 14 and 15, respectively. The output of the preamplifier 14 is directed to conventional sound reproducing equipment such as an amplifier, filter and loudspeaker. The outputs of the preamplifiers 13 and 15 are directed to separate decoding circuits containing a plurality (n) of band-pass filters arranged in parallel. That is, the output of the preamplifier 13 is supplied to the inputs of n band-pass filters 16, 17, 18 while the output of the preamplifier 15 is supplied to the inputs of n band-pass filters 19, 20, 21, 22 and 23.

It has been assumed, for the purposes of this illustrative embodiment, that there are two recording channels on the magnetic tape 9 containing encoded records and that each encoded record contains information defining a musical composition recorded at n different frequencies. It will be understood that the magnetic tape 9 may have encoded records on one track only or may have separate encoded records on three, four or up to eight separate tracks. The fewer or greater number of encoded records may be accommodated by fewer or added decoding systems containing band-pass filters in parallel.

It will also be appreciated that each encoded record may contain a greater or fewer number of band-pass filters than the n filters shown in FIG. 2.

The band-pass filters 16- 23 in the apparatus of FIG. 2 may be constructed as conventional series or parallel or series/parallel LC circuits. If the decoding device is to be connected to a player piano having an electromagnet arranged beneath each piano key to actuate the key (for example, as in the arrangement disclosed in the copending application, Ser. No. 79,043 filed concurrently with this application, by Karl F. Milde, Jr.) the inductance of each LC circuit (band-pass filter) may be formed by the coil of each piano key actuating electromagnet. In this case, it is preferable if the loudness of each note to be played is encoded as the amplitude of the signal representing that note. For example, if middle C were recorded on the track read by the head 10 at the frequency f.sub.2, a very loud C would be represented by a high amplitude signal while a soft C would be represented by a low amplitude signal at the frequency f.sub.2.

With the electromagnetic piano key actuating device mentioned above, a signal of high amplitude would cause the piano key representing middle C to be depressed with great force to produce a loud piano note. Similarly, a signal of minimum amplitude at frequency f.sub.2 would cause the piano key to be depressed with a minimum force thus producing a soft musical note.

The use of such a level encoding format is not limited to the case where the band-pass filters are formed, in part, by piano key actuating electromagnets. Accordingly, separate terminals 24, 25, 26, 27 and 28 are shown as pitch and level representing outputs in the decoding device of FIG. 2.

Where the musical level information is recorded in analog form on one or more separate frequencies, or in quantized form at a plurality of frequencies, the band-pass filters 16- 20 which pass the pitch information and the band-pass filters 21, 22 which pass the quality information may each be connected to a threshold gate 29, 30, 31, 32, 33, 34 and 35. These threshold gates eliminate noise by producing an output signal if and only if an input signal exceeds a given threshold level. As indicated by the arrow in each of the threshold gate boxes, the gates are preferably constructed with a variable threshold level to permit the decoding device to be adjusted for optimum performance.

The outputs of the threshold gates are indicated as terminals 36, 37, 38, 39, 40, 41 and 42. If a signal appears at a terminal, say, terminal 37, of the pitch representing terminals 36- 40, this signal indicates that a particular note, say, middle C, is being played. When a signal appears at a terminal, say, terminal 41, of the terminals 41, 42 representing the musical quality information, this signal indicates that the notes which are being played have a particular characteristic quality. Examples of musical quality may be the type of note (e.g., with a soft or a sharp attack characteristic) or the type of musical instrument (e.g., a particular organ stop or piano pedal).

With the decoding device shown in FIG. 2 it is assumed that the level information is recorded on the track of the magnetic tape 9 read by the head 12 at a separate frequency f.sub.n. Since only this frequency is passed by the band-pass filter 23 the level will be indicated by the amplitude of the signal appearing at the output terminal 43. The apparatus shown in FIG. 2 has been simplified, where possible, so as not to obscure the novel features characteristic of the present invention. As will be understood by those skilled in the art, it may be necessary to add additional circuit elements such as rectifiers and the like to produce a practical operative circuit.

FIG. 3 schematically illustrates the preferred embodiment of apparatus which decodes a musical composition recorded on a magnetic tape 44 in serial form in the manner described in the above-mentioned copending application, Ser. No. 79,046. This decoding apparatus operates to convert the serially arranged pitch information back into the parallel form.

As described in the application, Ser. No. 79,046, the presence of each note of at least a portion of the well-tempered scale is repeatedly scanned and, if a note is present, it is recorded on one track of the magnetic tape in the form of a pulse. This track, on which the pitch information is recorded, is "read" by the read head 47 and the signal passed through a preamplifier 49 to a negative pulse detector 51. This detector, which can consist, for example, of a rectifier arrangement, passes only negative reference pulses which appear at its input. These negative pulses signal the beginning and end of each complete scan.

The negative pulse detector 51 is connected to a frequency multiplier 52 and to an output terminal 70 labeled "Reset." The purpose of this output terminal will be discussed in detail below. The frequency multiplier produces an output pulse signal which is in phase with, and which is n times the frequency of the output of the pulse detector 51, where n is chosen so that the output signal of the frequency multiplier will equal the frequency at which successive notes of the well-tempered scale were originally scanned during the recording process. Thus, n is a whole number which is two greater than the number of notes scanned.

The frequency multiplier is connected to operate a counter 53, which produces a pulse at a different output upon receipt of each count and which may be reset by applying a pulse at a separate input. Whenever the counter is reset, the next counting pulse that is received will cause it to produce a signal at its first output, the following counting pulse will cause it to produce a signal at its second output, etc. In this way, the counter 53 can be operated in synchronism with the incoming information which was placed in serial form on the magnetic tape. The counter 53 receives its reset pulses from the output of the negative pulse detector 51; that is, the counter is reset every time a negative pulse is read from the magnetic tape 44.

All but one of the outputs of the counter 53 are connected to an individual one of a plurality of AND-gates 54, 55 and 56. As these outputs are consecutively activated by the counter 53, the AND-gates consecutively pass any pulse which appears on their other inputs; i.e., the inputs connected to the output of the preamplifier 49. This arrangement thus provides a "reverse scan" which places the serially incoming pulses in parallel form.

Each of the AND-gates 54 to 56 are connected, in turn, to one input of a respective flip-flop 57, 58 and 59. These flip-flops store the pitch information during each complete "reverse scan" until they are reset to their "no output" state by a pulse from the negative pulse detector 51. After each scan, and during the time that the counter 53 produces a signal at its last output, the information held in all the flip-flops is simultaneously gated out via AND-gates 60, 61 and 62 to separate output terminals 71, 72 and 77. The information which has been serially stored on the magnetic tape 44 has therefor been rearranged and is now presented in parallel form again.

Information regarding the level of the recorded music, which is stored in analog form on a separate track of the magnetic tape 44, is read by the read head 48, amplified in the preamplifier 50 and supplied to a separate output terminal 81. This information can be digitalized, if desired, by passing the analog level signal through any desired number of threshold gates, each adjusted to produce an output when the signal exceeds a different threshold level. As an example, FIG. 3 illustrates the apparatus necessary to indicate three levels of music: low, medium and high. The threshold gates 63, 64 and 65 have successively lower thresholds so that all but the faintest sounds will cause at least one of the three gates to produce an output. If the high threshold gate 63 produces an output, the signal appears on the terminal 78 labeled "Hi" and inhibits the signal produced by the threshold gate 64 from appearing at the terminal 79 with the aid of the INHIBIT-gate 66. If a signal appears at the output of the threshold gate 64, it will inhibit the appearance of the signal produced by the threshold gate 65 at the terminal 80 labeled "Lo" and, unless the threshold gate 63 has been activated, will appear at the terminal 79 labeled "Med".

The printer illustrated in FIG. 4 and the player piano device illustrated in FIG. 5 are both designed to be attached directly to the output terminals 70 to 81 of the apparatus of FIG. 3 or to the output terminals 36-43 of the apparatus of FIG. 2. If the printer is to be used, it must be connected to level outputs, such as outputs 78-80, which present the level information in digital form. Thus if the apparatus of FIG. 2 is to be used, a digitalizing device such as that shown in FIG. 3 (elements 63- 67) should be connected to the output 43 and the outputs 78-80 thereof connected to the printer.

The printer shown is of the type normally employed "on line" as an output device for an electronic computer. It comprises a plurality of drivers 82 each connected to a separate printing head 83. However, each printing head is capable of printing only one letter; namely, the letter of the alphabet designating the pitch of a single musical note or the letters "H", "M" and "L" which designate the level of the music as high, medium and low, respectively. The drivers are connected, as shown, to the terminals 71-80 of the apparatus of FIG. 3 or to the terminals 36-42 of the apparatus of FIG. 2. The paper advance device 84 is connected to the "Reset" terminal 70 when the printer is connected to the apparatus of FIG. 3, or to a variable frequency pulse generator when the printer is connected to the apparatus of FIG. 2.

The printer indicates the presence of all notes which were played during one printing cycle (e.g., the notes "C" and "A" shown in FIG. 4) in addition to the level of the music (shown as "M"). At the end of each cycle the reset pulse which appears at the terminal 70 causes the paper to advance. The "score" thus printed therefore indicates the pitch of each note by a printed letter and the position of the letter on the page; indicates the duration of each note by the number of times each letter is consecutively printed; and indicates the level of the music by the letters "L", "M" or "H" arranged conveniently at the top or bottom of the page. It will be appreciated that the quality information provided, e.g., at the outputs 41 and 42 of the apparatus of FIG. 2, may also be recorded by the printer on the score.

FIG. 5 illustrates an electromechanically actuated player piano which can likewise be connected to the outputs of the apparatus of FIGS. 2 or 3. Each of the gain-controlled amplifiers 85 is fed by one of the pitch indicating outputs 36 to 40 (FIG. 2) or 71 to 77 (FIG. 3) and controlled by the signal level at the level indicating outputs 43 or 81, respectively. The amplifiers are constructed in the manner well known in the art to increase their gain, and produce an output signal of greater voltage, with increasing signal level at their gain control input. In this way, the higher the level of the music recorded on tape, the louder will be the music played by the player piano.

Each controlled amplifier 85 is connected to a separate smoothing circuit 86, and then to the coil 90 of an electromagnet arranged beneath a piano key 91 to draw the key downward. Each smoothing circuit 86 functions to smooth separate consecutive pulses produced by the apparatus of FIG. 3 which indicate the presence of a single note, so that the electromagnet 90 remains actuated for the duration of each note. The smoothing circuits 86 may be eliminated when the player piano is connected to the apparatus of FIG. 2.

If the decoding apparatus of FIGS. 2 or 3 is to be connected to operate an electronic organ, the pitch indicating outputs 36- 40 (FIG. 2) or 71- 77 (FIG. 3) may be simply connected to actuate suitable electronic switches. These switches will have the same function in the organ circuit as the mechanical switches of the manual keyboard.

Regarding the utilization of the quality information encoded on the record medium and presented, for example, at terminals 41 and 42 in the apparatus of FIG. 2, it will be appreciated that the specific apparatus necessary for modifying the quality of the notes played will depend upon the nature of the quality information. For example, if the presence of a signal at the terminal 41 indicates that a particular piano pedal is to be depressed, this terminal may be connected to operate an electromagnetic pedal actuating device. Similarly, if the presence of a signal at the terminal 41 indicates that a particular organ stop is to be turned "on", this terminal may be connected to operate this organ stop.

It will be understood that the present invention is susceptible to various modifications, changes and adaptations as will occur to those skilled in the art. For example, the decoding apparatus of FIG. 3 may be operated to arrange serially encoded quality information in parallel form in a manner identical to that described in connection with the pitch information, if the quality information is also recorded on the magnetic tape 44. This quality information may be recorded on a separate track of the magnetic tape or may be "interlaced" on the same track or tracks with the pitch and/or level information.

It is therefore intended that the scope of the present invention be limited only by the following claims or their equivalents.

Claims

I claim:

1. Apparatus for reproducing music from a record of a musical composition, said record having at least one and no more than eight recording channels and having recorded, on a maximum of eight recording channels thereon, representations of the fundamentals of the musical notes of said composition encoded in serial form without inclusion of representations of the harmonics of said musical notes, said apparatus comprising, in combination:

a. means for reading said representations of the fundamentals of said musical notes from said record medium;

b. means, connected to said reading means, for decoding said fundamentals of said musical notes, said decoding means including:

1. means for periodically storing said fundamentals;

2. a plurality of output terminals; and

3. means for periodically gating out said fundamentals from said storage means to said output terminals, whereby the existence of each fundamental is represented by the presence or absence of a signal on a separate one of said output terminals; and

c. means, connected to said output terminals of said decoding means, for reproducing said musical notes.

2. The apparatus defined in claim 2, wherein said means for periodically storing said fundamentals includes:

i. a plurality of signal gates each having two input terminals and one output terminal, one of said input terminals of each of said gates being connected to receive a signal from said reading means;

ii. a plurality of storage elements, each connected to the output of a separate one of said signal gates; and

iii. scanning means, connected to the other of the input terminals of each of said signal gates, for gating individual ones of said signal gates in succession.