US3301118A

US3301118A - Piano acoustic pick up devices

Info

Publication number: US3301118A
Application number: US361731A
Authority: US
Inventors: Francis X Keane; Stanley H Michael
Original assignee: Individual
Current assignee: Individual
Priority date: 1964-04-22
Filing date: 1964-04-22
Publication date: 1967-01-31
Anticipated expiration: 1984-01-31

Description

5 Sheets-Sheet l lll llllll Fall 3l, 1967 F. x. KEANE ETAL PIANO ACOUSTIC PICK UP DEVICES Filed April 22, 1964 H Q .wo

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M1131, 1967 F. x. KEANE ETAL PIANO ACOUSTIC PICK UP DEVICES 3 Sheets-Sheet 2 Filed April 22, 1964 5. L E QM. M ,RNW U nl@ XH MY f. ci N L N c k MIL 3l, 1967 F. x. KEANE ETAL PIANO ACOUSTIC PICKAUP DEVICES Filed April 22, 1964 3 SheeiS-Sheet 5 United States Patent 3,301,118 PIANO ACOUSTIC PICK UP DEVICES Francis X. Keane, 43-22 63rd St., Woodside, N.Y. 11377, and Stanley H. Michael, 125 Prospect St., East Orange, NJ. 07017 Filed Apr. 22. 1964, Ser. No. 361,731 15 Claims. (Cl. 84-1) The present invention relates generally to acoustic pickup devices and more particularly concerns an acoustic support for a plurality of microphones on a piano or similar musical instrument.

The device embodying the invention has an elongated casing approximating in length the Width of a musical instrument, particularly a piano. Inside the casing is a plurality of closed, separate resonating chambers and a plurality of open sound chambers separate from each other. The chambers are all generally triangular in longitudinal section. Each of the sound chambers has two openings into which sound can enter. An electroacoustic microphone is centrally located in each sound chamber at its deepest point. The sound chambers are lined with sound-absorbing material to reduce sound reflections from the walls of the sound chambers. The sound in the chambers is reinforced and amplified by vibrations in the Walls of the resonating chambers. The microphones are equally spaced along the length of the device for picking up sound Iwaves of different frequency ranges emitted by the strings across the width of the frame supporting the strings. The microphones are all electrically in p-arallel and connected to an electrical output circuit including volume and tone controls for driving an extern-al audio amplifier. The circuit includes an input jack in circuit with volume and tone controls for applying external audio signals to be mixed with the audio signals produced by the microphones, for application to the external audio amplifier. The device includes slidable expansion bars at its ends so that the device can be supported on pianos of different Widths. The device is adapted for use with upright, console, spinet and grand pianos. The device can yalso be used with other musical instruments having wide sound producing arrays of strings, bars or other elements. Among these instruments may be harps, marimbas, xylophones, celestas, harpsichords, etc.

It is therefore a principal object of the invention to provide an elongated pickup device for sound vibrations from a wide musical instrument, with .a plurality of sound chambers in the device each picking up a predominantly different range of sound frequencies from the instrument.

Another object is to provide a device as described, with an electroacoustic type of microphone in each sound chamber isolated from each other microphone, the several microphones being connected in parallel to an .audio output circuit.

A further object is to provide a device as described with a plurality of resonating chambers in the device for -amplifying sound in the sound chambers.

Another object is to provide an improved sound pickup device for a piano or the like musical instrument to produce amplified high-fidelity reproduction of sounds of the instrument, with substantial linearization of the acoustic response characteristic of said device over the acoustic range of the instrument.

A further object is to provide an improved acoustic support for microphones in a spaced array on or in a piano or other wide musical instrument.

For further comprehension of the invention, and of thc objects .and advantages thereof, reference will be had to the following description and accompanying drawings, and to the appended claims in which the various novel 3,301,118 Patented Jan. 31, 1967 features of the invention are more particularly set forth.

In the accompanying drawings forming a material part of this disclosure:

FIG. 1 is .a reduced top plan view of a device embodying the invention shown mounted on a grand piano.

FIG. 2 is a perspective View of the device enlarged over FIG. l, the device being shown in an inverted position.

FIGS. 3, 4, 5 and 6 are enlarged sectional views taken on lines 3-3, 4 4, 5-5 yand 6 6, respectively, of FIG. 2.

FIG. 7 is a further enlarged top plan view of the device, parts being broken away.

FIG. 8 is -an exploded perspective view of parts of the inverted device.

FIG. 9 is a diagram illustrating the arrangement of sound and resonating chambers in the device.

FIG. l0 is a diagram of an electric circuit employed in the device.

FIG. l1 is a graphic diagram illustrating lacoustic response characteristics of the device.

Referring to the drawings, and particularly to FIGS.

' l-8, there is shown a device D embodying the invention.

This device includes an elongated rectangular casing 20 having lateral

xed side walls

22, 24,

end walls

26, 28, and top wall 30. A removable bottom rectangular panel 32 is fitted in the open bottom of the casing. A supplemental shorter rectangular panel 34 is removably iitted in the bottom of the casing for closing a compartment C in which the components C of an electric circuit are contained.

The interior of the casing 20 contains intermediate xed, oblique partitions 38. These partitions define with top wall 30, end wall 26, and cross partition 42, five generally triangular, closed, separate resonating chambers RI-RS. As shown in the diagram of FIG. 9, these chambers have their apices at the bottom of the casing and their bases at the top. End chambers R1 and R5 are about half the sizeof intermediate chambers R2-R4. Between the bottom panel 32 and the intermediate obliquely dis- A posed partitions 38 yare defined four separate generally triangular sound-receiving chambers S1-S4. The chambers Rl-RS and S1-S4 occupy substantially the entire internal volume of the casing except for compartment C. The undersides of partitions 38 are lined with sound absorbing sheet material 44 such as felt.

In panel 32 and uniformly spaced apart along this panel are four pairs of ports or holes 46a, 46b; 47a, 47b; 48a, 48b; and 49a, 49b. Each pair of holes open near o'pposite narrow ends of a triangular sound chamber. A screen or grille 50 is secured to the inner side of the panel 32 over each of the eight holes. The screens may be secured by staples 52 or other suitable fastening means. The sound cham-bers Sil-S4 are arranged as indicated in FIG. 9 so that their apices are at the top 30 of the device and their wide bases or bottoms are at the bottom panel 32. Each of the end walls of the sound chambers defined by the oblique partitions 38 is common to one of the end walls of each of the five resonating chambers. It will be noted that sound chamber SI is located between resonating chambers Rl, R2; sound chamber S2 is between resonating chambers RZ, R3; sound chamber S3 is between resonating chambers R3, R4; and sound chamber S4 is between resonating chambers R4, R5. Each of the sound chambers thus has two adjacent resonating chambers, and each of the intermediate resonating chambers R2-R4 `is common to two adjacent sound chambers.

Centrally located at the base of each of the sound chambers on panel 32 is a resilient rubber or felt pad 54. Secured to the underside of this pad is one of four electro-acoustic microphones 55-58. The microphone is thus located opposite the vertex or apex of each sound chamber, at its deepest part. The face of the microphone is exposed to sound arriving through each of the pair of ports or holes in the sound chamber. The microphones are electrically connected in parallel to a dual wire cable 60 and terminate at an electrical circuit in compartment C which is described below in connection with FIG. 10. Felt pads 59 line sides of chambers S1-S4 at the microphones.

Panels

32 and 34 can be removably secured in the casing 20 by

nails

61, 62 inserted through the

side walls

22, 24 into lateral edges of the panels. In addition, screws 64 can be applied at ends of the panel 32. When the panels 32 and 3ftare properly installed, the compartment C is closed and chambers S144 are closed at their ends and separate from each other. In order to permit the cable 60 to extend lengthwise along the panel 32, recesses 65 are provided in the partitions 38 at the en-ds of the sound chambers in which the cable 60 iits in passing from one sound chamber to the next and to the compartment C. Staples 67 hold cable 60 on panel 32.

Adjustable supports are provided at opposite ends of the ca-sing for mounting it on pianos of different widths. At each end of the casing on top wall 30 is a resilient, sound-absorbing pad 70 made of cork, rubber or the like. Attached to this pad is a block 72. A `bracket plate 74 may be attached to block 72 by screws 75 inserted through holes 76 in the plate 74. Between each plate 74 and mounting block 72 is la slidable bar 77. Bar 77 has an outer downwardly turned end flange 78 to prevent lengthwise movement of the device off of the sides of piano casing PC shown in F IG. 1. A centrally located, longitudinally arranged slot 80 is provided in bar 77 through which screws 75 extend. On opposite sides of the bar 77 lare resilient felt strips 82, 84. These felt strips protect the piano casing from scratching and also prevent transmission of sounds from the casing to the device through bars 77. The screws 75 are adjusted so that the bars 77 can slide inwardly or outwardly of opposite ends of the casing to vary the overall length of the device.

' At the top wall 30 i-s an elongated opening 85 in which is a plate 86 on which are exposed volume and tone control knobs' 88 and jacks 89, 90 of the circuit components in compartment C. The circuit 100 in which the microphones 55-58 are connected is shown in FIG. 10. Microphone 55 is the low frequency microphone. It may be connected at one terminal in series with a capacitor 102 to wire or line 60a. Line 60h is grounded at the other terminal of the capacitor'. Low-middle frequency microphone 56 is connected at one terminal in series with a capacitor 104 to line 60a while the other terminal is connected to ground line 60b. Middle-high frequency microphone 57 is connected at one terminal via resistor 108 to line 60a. High frequency microphone 58 is connected at one terminal via resistor 110 to line 60a. The other terminals of the

microphones

57, 58 Aare connected to ground line 60h.

The audio signal line 60a is connected to volume control 112. This is a rheostat which is -connected via audio line 115 to output jack 89. A conventional phone plug can be inserted into this jack for connection of the audio output of the microphones to an external audio amplifier. A capacitor 114 can be connected between line 60a and ground to by-pass undesired very high frequencies or overtones to ground. A tone control circuit is associated with the microphone output. This tone control circuit includes a capacitor 116 connected between audio line 115 and a tone control 118. The tone control is a rheostat 'connected to ground in series with the capacitor 116. The circuit 100 includes a mixer input circuit.

The mixer input circuit has a jack 90 to which a phone plug can be connected for applying audio signals from an external source. The jack 90 is connected via audio wire 120 to a volume control 122. This control is a rheostat which may be grounded for very high frequencies via capacitor 124 to ground. The volume control 122 is connected to audio output line 115. A tone control 125 is lassociated with the mixer input circuit. This tone control is a rheostat connected between capacitor 126 and ground. Capacitor 126 is connected to the audio line 115. The several control knobs 88 of the volume and tone controls 112, 118, 122, are exposed at the top of the device as shown in FIGS. 1 and 7 for convenient operation by the player of the piano P.

The device can be extended across the piano casing andA supported on the sides of the casing. The device will overlay the strings S of the piano in such a way that low frequency sound chamber S1 picks up predominantly low frequencies from the bass strings of the piano. The sound chamber S2 will pick up sound frequencies in the bass to middle tones. The sound chamber S3 will pick up sound frequencies in the middle to high range. Sound chamber S3 will pick up predominantly treble tones. The compressional sound waves entering the sound chambers will impinge on partitions 38 and cause damped vibrations in the resonating chambers. The felt layers 44 will tend to prevent reflections of sounds from the vibrating walls 38.

The sound vibrations in the sound chambers S1S4 will be reinforced by the vibrating partitions or walls 38 and the amplified sound waves will be applied to the microphone in each sound chamber. By introducing the sound waves 4into each sound chamber through two laterally spaced holes a better blending of sound and coverage of the assigned frequency range for each microphone is obtained. Since each microphone has two adjacent resonating chambers at its ends both resonating at different frequencies, smoothing and general linearization of the audio response characteristic A of the device is achieved as indicated by the solid line in FIG. 1l. Some overlap occurs at the ends of the frequency ranges in which the several microphones receive sounds. Thus, as shown in FIG. l1, the audio response characteristics L and L-M of the

microphones

55, 56 respectively, shown in dotted lines, overlap to effect linearization of characteristic A at the overlap O1 of the low and low-middle frequency range. Similarly, the characteristics L-M and M-H overlap for

microphones

56, 57 to linearize the characteristic A at the overlap O2 of low-middle and middle-high ranges. Finally, the dotted line characteristics M-H and H overlap for

microphones

57, 58 to linearize characteristic A -at the frequency overlap O3.

The device thus effectively produces high fidelity reproduction of the sounds of the piano over its entire frequency range. By judicious adjustment of the volume and tone controls desirable variations can be introduced into the audio characteristic A depending on the particular ambient acoustic conditions prevailing, the type of music being played, acoustic modifications and effects desired, etc.

lThe invention thus provides more effective variation and control of sound pickup from a piano or any other instrument having a Wide array of strings, bars, bells or other tone producing elements. The casing of device D is preferably made of wood, but parts could be made of metal or plastic. It is light in weight, inexpensive to manufacture, attractive in appearance, and easy to use. If desired, the volume and tone controls can be preset for certain desired acoustic effects, or the user can be provided with a chart showing graphically different acoustic effects obtained by different settings of the controls. In any case, the acoustic results obtained from the external amplifier will serve as a means by which adjustment of the controls of device D can be monitored.

While we have illustrated and described the preferred embodiment of our invention, it is to be understood that we do not limit ourselves to the precise construction herein disclosed and that various changes and modifications may be made within the scope of the invention as defined in the appended claims.

Having thus described our invention, what we claim as new, and desire to secure by United States Letters Patent 1s:

1. A pickup device for musical tones produced by an instrument having a wide array of tone producing elements, comprising an elongated casing having top, bottom, side and end walls, a plurality of partitions in said casing obliquely disposed to define a plurality of generally triangular, separate sound receiving chambers with bases at the bottom wall and apices at the top wall, said bottom wall having a plurality of pairs of holes therein, each pair of holes opening into a different one of the sound chambers near narrow ends thereof, a plurality of electro-acoustic microphones supported on said bottom wall, a different one of the microphones being centrally located in each of the sound chambers in alignment with the apex thereof with the microphone located between the holes in one of said pairs, and circuit means interconnecting the microphones for applying audio signals produced thereby to an external circuit.

2. A pickup device for musical tones produced by an instrument having a wide array of tone producing elements, comprising an elongated casing having top, bottom, side and end walls, a plurality of partitions in said casing obliquely disposed to define with said bottom wall a plurality of generally triangular, separate sound receiving chambers with bases at the bottom wall and apices at the top wall, said bottom Wall having a plurality of pairs of holes therein, each pair of holes opening into a different one of the sound chambers near narrow ends thereof, sound absorbing material on said partitions in said sound chambers to reduce sound reflections therefrom, said partitions further defining with the top wall a plurality of closed triangular sound resonating chambers, two of said resonating chambers `being disposed adjacent to opposite ends of each of the sound receiving chambers, with each two adjacent sound receiving chambers having adjacent ends common to a different single one of the resonating chambers, a plurality of electro-acoustic microphones supported on said bottom wall, a different one of the microphones being centrally located in each of the sound chambers in alignment with the apex thereof with the mic-rophone located between the holes in one of said pairs, and circuit means interconnecting the microphones for applying audio signals produced thereby to an external circuit.

3. A pickup device for musical tones produced by an instrument having .a wide array of tone producing elements, comprising an elongated casing having top, bottom, side and end walls, a plurality of partitions in said casing obliquely disposed to define a plurality of generally triangular, separate sound receiving chambers with bases at the bottom wall `and apices at the top wall, said bottom Wall having a plu-rality of pairs of holes therein, each pair of holes opening into a different one of lthe sound chambers near narrow ends thereof, a plurality of electro-acoustic microphones supported on said Ibottom wall, a different one of the microphones being centrally located in each of the sound cham-bers in alignment with the apex thereof with the microphone loca-ted between the holes in one of said pai-rs, circuit means interconnecting the microphones for applying audio signals produced thereby to an external circuit, and adjustable slidable supports on opposite ends of the casing for supporting said casing over the tone producing elements of the said instrument with the holes in the sound receiving chambers located to receive predominantly different ranges of sound frequencies.

4. A pickup device for musical tones produced by an instrument having .a wide array of tone producing elements, comprising an elongated casing having top, bottom, side and end walls, a plurality of partition-s in said casing obliquely disposed to define with said bottom wall a plurality of generally triangular, separate sound receiving chambers with bases at the bottom wall and apices at the top wall, said bottom Wall having a plurality of pairs of holes therein, each pair of holes opening into a different one of the sound chambers near narrow ends thereof, sound absorbing material on said partitions in said sound chambers to reduce sound reflections therefrom, said partitions further defining with the top wall a plurality of closed triangular sound resonating chambers, two of said resonating chambers being disposed adjacent to opposite ends of each of the sound receiving chambers, with each two adjacent sound receiving chambers having adjacent ends common to a different single one of the resonating chambers, a plurality of electro-acoustic microphones supported on said bottom wall, a different one of the microphones being centrally located in each of the sound chambers in alignment with the apex thereof with the microphone located between the holes in one of said pairs, circuit means interconnecting the microphones for applying audio signals produced thereby to an external circuit, and adjustable slidable supports on opposite ends of the casing for supporting said casing over the tone producing elements of the said instrument with the holes in the sound receiving chambers located to receive predominantly different ranges of sound frequencies.

5. A pickup device for musical tones produced by an instrument having .a wide array of tone producing elements, comprising an elongated casing having top, bottom, side Iand end walls, a plurality of partitions in said casing obliquely disposed to define with said bottom wall a plurality of generally triangular, separate sound receiving chambers with bases at the bottom wall and Iapices at the top wall, said bottom wall having a plurality of pairs of holes therein, each pair of holes opening into a different one of the sound chambers near narrow ends thereof, sound absorbing material on said partitions in said sound chambers t-o reduce sound reflections therefrom, said partitions further defining with the top wall a plurality of closed triangular sound resonating chambers, two of said resonating chambers being disposed adjacent to opposite ends of each of the sound receiving chambers, with each two adjacent sound receiving charnbers having adjacent ends common to a different single one of the resonating chambers, a plurality of electroacoustic microphones supported on said bottom wall, a difierent one of the microphones being centrally located in each of the sound chambers in alignment with the apex thereof with the microphone located between the holes in one of said pairs, circuit means interconnecting the microphones for applying audio signals produced thereby to an external circuit, said partitions being common to adjacent sound resonating and sound receiving chambers and vibrating therebetween so that substantial linearization is effected of the acoustic response characteristic of the microphones over the sound frequency producing range of said instrument, and means on ends of the casing for supporting the same over the tone producing elements of said instrument so that each sound receiving chamber picks up predominantly a different range of sound frequencies.

6. A pickup device for musical tones produced by an instrument having a wide array of t-one producing elements, comprising an elongated casing having top, bottom, side -and end walls, a plurality of partitions in said casing obliquely disposed to define with said bottom Wall a plurality of generally triangular, separate sound receiving chambers with bases at the bottom wall and apices at the top wall, said bottom wall having a plurality of pairs of holes therein, each pair of holes opening into a different one of the sound chambers near narrow ends thereof, sound absorbing material on said partitions in said sound chambers to reduce sound reflections therefrom, said partitions further defining with the top wall a plurality of closed triangular sound resonating chambers, two of said resonating chambers being disposed adjacent to opposite ends of each of the sound receiving chambers, with each two adjacent sound receiving chambers having adjacent ends common to a different single one of the resonating chambers, said partitions being common to adjacent sound resonating and sound receiving chambers and vibrating therebetween so that loverlapping occurs at ends of the -sound frequency ranges which adjacent sound receiving chambers receive whereby the acoustic response characteristic of the sound receiving chambers is substantially linearized, and further sound absorbing material on the side walls and bottom wall inside each sound receiving chamber for surrounding a microphone in each sound receiving chamber to minimize sound reflections from the side and bottom walls.

7. A pickup device for musical tones produced by an instrument having a wide array of tone producing elements, comprising an elongated casing having top, bottom, side and end walls, a plurality of partitions in said casing obliquely disposed to define with said bottom wall a plurality of generally triangular, separate sound receiving chambers with bases at the lbottom wall and apices at the top wall, said bottom wall having a plurality of pairs of holes therein, each pair of holes opening into a different one of the sound chambers near narrow ends thereof, sound absorbing material on said partitions in said sound chambers to reduce sound reflections therefrom, said partitions further defining with the top wall la plurality of closed triangular sound resonating chambers, two of said resonating chambers being disposed adjacent to opposite ends of each of the sound receiving chambers, with each two adjacent sound receiving chambers having adjacent ends common to a different single one of the resonating chambers, said partitions being common to adjacent sound resonating and sound receiving chambers and vibrating therebetween so that overlapping occurs at ends of the sound frequency ranges which adjacent sound receiving chambers receive whereby the acoustic response characteristic of the sound receiving chambers is substantially linearized, a plurality of electro-acoustic microphones supported on said bottom wall, Ia different one of the microphones being located in each sound receiving chamber between the pair of holes opening therein, another partition in said casing defining with said top, bottom and side walls an end compartment, circuit means connecting the microphones in parallel, and an output terminal in said compartment connected to said circuit means for applying audio signals from said microphones to an external amplifier.

8. A pickup device for musical tones produced by an instrument having a wide array of tone producing elements, comprising an elongated casing having top, bottom, side and end walls, a plurality of partitions in said casing obliquely disposed to define with said bottom wall a plurality of generally triangular, separate sound receiving chambers with bases at the bottom wall and apices at the top wall, said bottom wall having a plurality of pairs of holes therein, each pair of holes opening into a different one of the sound chambers near narrow ends thereof, sound -absorbing material on said partitions in said sound chambers to reduce sound reflections therefrom, said partitions further defining with the top wall a plurality of closed triangular sound resonating chambers, two of said resonating chambers being disposed adjacent to opposite ends of each of the sound receiving chambers, with each two adjacent sound receiving chambers having adjacent ends common to a different single one of the resonating chambers, said partitions being common to adjacent sound resonating and sound receiving chambers and vibrating therebetween so that overlapping 'occurs at ends of the sound frequency ranges which adjacent sound receiving chambers receive whereby the acoustic response characteristic of the sound receiving chambers is substantially linearized, and further sound absorbing material on the side walls and bottom wall inside each sound receiving chamber for surrounding a microphone in each sound receiving chambers to minimize sound reflections from the side and bottom walls, means on ends of the casing for supporting the same over the tone producing elements of the instrument so that each sound receiving chamber picks up predominantly a different range of sound frequencies.

9. A pickup device for musical tones produced by an instrument having a wide array of tone producing elements, comprising an elongated casing having top, bottom, side and end walls, a plurality of partitions in said casing obliquely disposed to define with said bottom wall av plurality of generally triangular, separate sound receiving chambers with bases at the bottom wall and apices at the top wall, said bottom wall having a plurality of pairs of holes therein, each pair of holes opening into a different one of the sound chambers near narrow ends thereof, sound absorbing material on said partitions in said sound chambers to'reduce sound reflections therefrom, said partitions further defining with the top wall a plurality of closed triangular sound resonating chambers, two of said resonating chambers being disposed adjacent to opposite ends of each of the sound receiving chambers, with each two adjacent sound receiving chambers having adjacent ends common to a different single one of the resonatingv chambers, a plurality of electro-acoustic microphones supported on said bottom wall, a different one of the microphones being centrally located in each of the sound chambers in alignment with the apex thereof with the microphone located between the holes in one of said pairs, and circuit means interconnecting the microphones for applying audio signals produced thereby to an external circuit, said circuit means interconnecting the microphones in parallel, meansdening a compartment in said casing, a circuit output terminal in said compartment, a volume control and a tone control in circuit with said circuit means and said circuit terminal whereby audio signals produced by the microphones are applied to said circuit terminal under control of the volume and tone controls.

10. A pickup device for musical tones produced by an instrument having a wide array of tone producing elements, comprising an elongated casing having top, bottom, side and end walls, a plurality of partitions in said casing obliquely disposed to deline with said bottom wall a plurality of generally triangular, separate sound receiving chambers with bases at the bottom wall and apices at the top wall, said bottom wall having a plurality of pairs of holes therein, each pair of holes opening int-o a different one of the sound-chambers near narrow ends thereof, sound absorbing material on said partitions in said sound chambers to reduce sound reflections therefrom, said partitions further defining with the top wall a plurality of closed triangular sound resonating chambers, two of said resonating chambers being disposed adjacent to opposite ends `of each of the sound receiving chambers, with each -two adjacent sound receiving chambers having adjacent ends common t-o a different single one of the resonating chambers, a plurality of electroacoustic microphones supported on said bottom wall, a different one of the microphones being centrally located in each of the sound chambers in alignment with the apex thereof with the microphone located between the holes in one of said pairs, and circuit means interconnecting the microphones for applying audio signalss produced thereby to an external circuit, said circuit means interconnecting the microphones in parallel, means deiining a compartment in said casing, a circuit output terminal in said compartment, a volume control and a tone control in circuit with said circuit means and said circuit terminal whereby audio signals produced by the microphones are applied to said circuit terminal under control of the volume and tone controls, a circuit input terminal in said compartment, another volume control and another tone control in circuit with said circuit output terminal whereby externally produced audio frequency signals can be mixed with the audio signals produced by the microphones.

11. A pickup device for musical tones produced by an instrument having a wide array 'of tone producing elements, comprising an elongated casing having top, bottom, side and end walls, a plurality of partitions in said casing obliquely disposed to define with said bottom wall a plurality of generally triangular, separate sound receiving chambers with bases at the bottom wall and Aapices at the Itop wall, said bottom wall having a plurality of pairs of holes therein, each pair of holes opening into a different one of the sound chambers near narrow ends thereof, sound absorbing material on said partitions in said sound chambers to reduce sound reflections therefrom, said partitions further defining with the top wall a plurality of closed triangular sound resonating chambers, two of said resonating chambers being disposed adjacent to opposite ends of each of the sound receiving chambers, with each two adjacent sound receiving chambers having adjacent ends common to a different single one of the resonating chambers, a plurality of electro-acoustic microphones supported on said bottom wall, a different one of the microphones being centrally located in each of the sound chambers in alignment with the apex thereof with the microphone located between the holes in one of said pairs, and circuit means interconnecting the microphones for applying audio signals produced thereby to an external circuit, said circuit means interconnecting the microphones in parallel, means defining a compartment in said casing, a circuit output terminal in said compartment, a Volume control and a tone control in circuit with said circuit means and said circuit terminal whereby audio signals produced by the microphones are applied to said circuit terminal under control of the volume and tone controls, and adjustable slidable supports on opposite ends of the casing for supporting said casing over the tone producing elements of the said instrument with the holes in the sound receiving chambers located to receive predominantly different ranges of sound frequencies.

12. A pickup device for musical tones produced by an instrument having a wide array of tone producing elements, comprising an elongated casing having top, bottom, side and end walls, a plurality of partitions in said casing obliquely disposed to define with said bottom wall a plurality of generally triangular, separate sound receiving chambers with bases at the bottom wall and apices at the top wall, said vbottom wall having a plurality of pairs of holes therein, each pair of holes opening into a dif-ferent one of the sound chambers near narrow ends thereof, sound absorbing material on said partitions in said sound chambers to reduce sound reflections therefrom, said partitions further defining with the top wall a plurality of closed triangular sound resonating chambers, two of said resonating chambers being disposed adjacent to opposite ends of each of the sound receiving chambers, with each two adjacent sound receiving chambers having adjacent ends common to a different single one of the resonating chambers, a plurality of electro-acoustic microphones supported on said bottom wall, a different one of the microphones being centrally located in each of the sound chambers in alignment with the apex there-of with the microphone located between the holes in one of said pairs, circuit means interconnecting the microphones for applying audio signals produced thereby to an external circuit, said partitions being common to adjacent sound resonating and sound receiving chambers and vibrating therebetween so that substantial linearization is effected of the acoustic response characteristic of the microphones over the sound frequency producing range of said instrument, and means on ends of the casing for supporting the same over the tone producing elements of said instrument so that each sound receiving chamber picks up predominantly a different range of sound frequencies, said circuit means interconnecting the microphones in parallel, means defining a compartment in said casing, a circuit output terminal in said compartment, a volume control and a tone control in circuit with said circuit means and said circuit terminal whereby audio signals produced by the microphones are applied to said circuit terminal under control of the volume and tone controls, a circuit input terminal in said compartment, another volume control and another tone control in circuit with said circuit output terminal Whereby externally produced audio frequency signals can be mixed with the audio signals produced by the microphones.

13. A pickup device `for musical tones produced by an instrument having a wide array of tone producing elements, comprising an elongated casing having top, bottom, side and end walls, a plurality of partitions in said casing obliquely disposed to define with said bottom wall a plurality of generally triangula-r, separate sound receiving chambers with bases at the bottom wall and apices at the top wall, said bottom wall having a .plurality of pairs of holes therein, each pair of holes opening into a different one of the sound chambers near narrow ends thereof, sound absorbing material on said partitions in said sound chambers to reduce sound reflections therefrom, said partitions further defining with the top wall a plurality of closed triangular sound resonating chambers, two of said resonating chambers being disposed adjacent to opposite ends of each of the sound receiving chambers, with each two adjacent sound receiving chambers having adjacent ends common to a different single one of the resonating chambers, a plurality of electro-acoustic microphones supported on said bottom wall, -a different one of the microphones bein-g centrally located in each of the sound chambers in alignment with the apex thereof with the microphone located between the holes in one of said pairs, circuit means interconnecting the microphones for applying audio signals produced thereby to an external circuit, and adjustable slidable supports on opposite ends of the casin-g for supporting said casing over the tone producing elements of the said instrument with the holes in the sound receiving chambers located to receive predominantly different ranges of sound frequencies, said circuit means interconnecting the microphones in parallel, means defining a compartment in said casing, a circuit output terminal in said compartment, a volume control and a tone control in circuit with said circuit means and said circuit terminal whereby audio signals ,produced by the microphones are applied to said circuit terminal under control of the volume and tone controls.

I14. A pickup device for musical tones produced by an instrument having a wide array of tone producing elements, comprising an elongated casing having top, bottom, side and end walls, a plurality of partitions in said casing obliquely disposed to define with said bottom wall a plurality of ygenerally triangular, separate sound receiving cham-bers with bases yat the bottom wall and apices at the top wall, said bottom wall havin-g a plurality of pairs of holes therein, each pair of holes opening into a different one of the sound chambers near narrow ends thereof, sound absorbing material on said partitions in said sound chambers to reduce sound reflections therefrom, said partitions further defining with the top wall a plurality of closed triangular sound resonating chambers, two of said resonating chambers being disposed adjacent to opposite ends of each of the sound receiving chambers, with each two adjacent sound receiving chambers having adjacent ends common to a different single one of the resonating chambers, a plurality of electro-acoustic microphones supported on said bottom wall, a different one of the microphones being centrally located in each of the sound chambers in alignment with the apex thereof with the microphone located between the holes in one of said pairs, circuit means interconnecting the microphones for applying audio signals produced thereby to an external circuit, and adjustable slidable sup-ports on opposite ends of the casing for supporting said casing over the tone ,producing elements of the said instrument with the holes in the sound receiving chambers located to receive predominantly different ranges of sound frequencies, said circuit means interconnecting the microphones in parallel, means -defining a compartment in said casing, a circuit output terminal in said compartment, a volume control and a tone control in circuit with said circuit means and said circuit terminal whereby audio signals produced by the microphones are applied to said circuit terminal under control of the volume and tone controls, a -circuit input terminal in said compartment, another volume control and another tone control in circuit With said circuit output terminal whereby externally produced audio frequency signals can be mixed With the audio signals produced by the microphones.

15. A pickup device for musical tones produced by an instrument having a Wide `array of tone producing elements, comprising an elongated casing having top, bottom, side and end Walls, a plurality of partitions in said casing obliquenly disposed to dene a plurality of separate sound-receiving chambers With bases at the bottom Wall and apices at the top Wall, said bottom wall having a plurality of openings therein, at least one of the openings entering each chamber, a plurality of electro-acoustic microphones supported on said bottom wall, a different one of the microphones being located in each of the sound chambers and removed from the opening, and circuit means interconnecting the microphones for applying audio signals produced thereby to an external circuit.

References Cited by the Examiner UNITED STATES PATENTS 2,716,370 8/1955 Sano 84-376 X 2,798,397 7/1957 Frigo et al. 84-376 X 2,927,167 3/1960 Michael 84-1.l6 X 3,049,958 8/1962 Benio 841.16 3,084,538 4/196-3 Anderson 84-1.16 3,175,448 3/1965 Cardoza 84-127 RICHARD B. WILKINSON, Primary Examiner.