US 3543629 A
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United States Patent Inventors Lester M. Barcus 2S2| Tivoli John F. Berry, 4020 Fountain St., Long Beach, California Appl. No. 716,441
Filed March 27, 1968 Patented Dec. 1, 1970 ELECTRICAL PICKUP LOCATED IN MOUTHPIECE OF MUSICAL INSTRUMENT UTILIZING PIEZOELECTRIC TRANSDUCER l 1 Claims, 4 Drawing Figs.
u.s. Cl 194/144, 84/l.0l, 84/398, 84/462 Int. Cl Gl0h 3/00 Field of Search 84/1 .01,
[ 5 6] References Cited UNITED STATES PATENTS 2,383,553 8/1945 Johnson 84/'1.15x 2,984,140 5/1961 Barron... 84/l.15X 3,429,976 2/1969 Tomcik s4/1.12
Primary Examiner-Herman Karl Saalbach Assistant Examiner-T. Vezeau Attorney-Fulwider, Patton, Rieber, Lee & Utecht ABSTRACT: A mouthpiece for a musical instrument such as the trumpet, trombone or the like, and including a transducer utilizing piezoelectric material to produce electrical signals in response to pressure differences or waves developed within the mouthpiece.
stnc'rcnr. PICKUP LOCATED in Mon'rnrtnct: or Musician INSTRUMENT lUTllLllZlNG PIEZOELEQETQ rnANsnucnn CROSS-REFERENCE TO RELATED APPLICATIONS The present invention is generally related to the subject matter of our US. Pat. No. 3,325,580, issued June 13, 1967, and entitled MUSICAL INSTRUMENT UTILIZING PIEZOELECTRIC TRANSDUCER". However, the invention described in that patent relates to the use of piezoelectric material under continuous compressive force to provide electrical signals in response to changes in the magnitude of such force incident to vibrations of the compressing body.
In contrast, the piezoelectric transducer of the present invention is essentially unresponsive to the body within which it is mounted, being responsive primarily to pressure fluctuations occurring within the cavity or cup defined by the mouthpiece body and the lips of the player.
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to musical instruments and particularly to those of such instruments which utilize brass mouthpieces or the like.
2. Description of Prior Art The achievement of high fidelity reproduction or amplification of the sound of musical instruments of the brass family has been long sought in the prior art. The approaches obvious to those skilled in the art have been tried and all have failed.
Conventional recording techniques utilizing usual microphones have enabled the recording of musical performances with reasonable fidelity, but great care must be exercised in isolating unwanted sounds from the microphones. The performers obviously cannot speak to one another, the crackle of turning pages would spoil the recording, and the thump of a kicked music stand or dropped music would require another recording effort. The microphones are mercilessly responsive to all such sounds.
Utilization of microphones at concert or club appearances is even more prone to result in amplification of unwanted sounds because the acoustical character of the room or hall is designed for public performances and not for microphone pickups.
Efforts have been made to incorporate a conventional microphone in smaller form within the instrument itself, but it has been found that mechanical sounds such as valve noises and brushing of exterior objects or materials against the instrument are also amplified. The proper location on the instrument for such a microphone is also dilficultshould there be several microphones at different locations, or simply one microphone and, if one, where should it be placed to achieve the desired high fidelity SUMMARY OF THE INVENTION The present invention is a mouthpiece which mounts a transducer utilizing piezoelectric material of a type and in an arrangement such that the material is essentially responsive to those pressure fluctuations which are developed in the mouthpiece by the players lips and modified by the shape and length of the air column defined by the body of the particular instrument. More particularly, the piezoelectric material is located adjacent the inner surface of the mouthpiece, in the area where essentially all of the sounds unique to the instrument occur.
The piezoelectric material is of a type or is mounted so as to be essentially unresponsive to vibrations of the mouthpiece itself, that is, essentially unresponsive to vibrational waves propagated by and through the material of the mouthpiece. Consequently, for all practical purposes, not only sounds emanating from sources located externally of the instrument, but also sounds propagated through the instrument body and the mouthpiece are completely isolated from the sensitive piezoelectric material. The present mouthpiece is therefore generally discriminative in its sensitivity to musical versus nonmusical sounds.
Other objects and features of the invention will become apparent from consideration of the following description taken in connection with the accompanying drawings, in which:
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a mouthpiece according to the present invention, and adapted for use with a brass instrument such as a trumpet;
FIG. 2 is a view taken along lines 2-2 of FIG. 1;
FIG. 3 is an enlarged view of that portion of FIG. 2 which illustrates the mounting of the piezoelectric material; and
FIG. 4 is an enlarged view taken along the line 4-4 of FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, there is illustrated a mouthpiece 10 which, but for its modification to incorporate certain structure of the present invention, is identical to conventional mouthpieces presently available for use with instruments of the brass family, such as trumpets or trombones. Although the invention is envisioned as having its primary ap plication to the mouthpieces of musical instruments of the brass family, it will be apparent that it is equally applicable to any mouthpiece within which are developed fluctuating pressures representative of the musical sounds of the associated instrument.
The mouthpiece 10 includes a cylindrical shank 12 adapted to complementally fit upon the body (not shown) of a trumpet, for example. The shank 12 is integral with a radially outwardly flaring or conical cup 14 which forms the main part of the mouthpiece 10, and against which the player presses his lips during playing.
The players lips constitute vibratile elements which develop compressions and rarefactions of the air column defined by the musical instrument body (not shown). The instrument body modifies such compressions and rarefactions according to its shape and length, and according to modifications made in such length by operation of valves or the like, as is well known.
We have found that it is within the mouthpiece chamber 16 defined by the concave inner surface of the mouthpiece cup 14 that pressure differences and fluctuations occur which are representativeof the unique character of the instrument.
Consequently, a transducer employing piezoelectric material 18 is located adjacent the concave inner surface of the mouthpiece 10. Location anywhere along such surface will yield satisfactory results, but it has been found that location of the material 18 is preferably slightly closer to the smaller end of the cup 14, as illustrated.
The material 18 is selected for sensitivity to pressure fluctuations or waves actinggenerally normal to its outer face, and is preferably a thickness-expander plate or disk of polycrystalline electromechanically sensitive dielectric material such as barium titanate or Iead-zirconate-titanate ceramic. Such a material produces an electrical signal in response to varying pressures or mechanical vibrations applied in the thickness mode. Preferably the material 18 is productive of such a signal directly upon its compressive deformation, although it is comtemplated that piezoresistive materials could be used whose deformation in a thickness mode merely affects its resistivity, and consequently the character of electrical signals applied to it by an external circuit.
The material 18 is provided with opposite, electrically conductive layers which constitute electrodes 20 and 22, as is well known to those skilled in the art. A signal lead 24 and a ground lead 26 are connected to the electrodes 20 and 22, respectively, and are extended out of a suitable opening 27 in the mouthpiece 10 for connection to an external circuit, which is generally indicated at 28. The lead 24 is insulated from its point of emergence from the mouthpiece 10, while the surrounding ground lead is soldered to the mouthpiece adjacent the opening 27.
The nature of the circuit 23 is not a part of the present invention and it will therefore not be described, other than to indicate that it could be recording system, a radio or television broadcast system, an amplification system or the like, any of which could also include formant filters or the like for modifying the character of the output signals of the material 18 as desired.
The material 18 is preferably round, with a thickness less than its diameter. Typically, the diameter is 0.250 inches and the thickness is 0.030 inches.
It is important to note that the thicker the material 18, the more efficiently it responds to vibrations in its vertical or thickness mode. Moreover, the thicker it is, the less the mechanical coupling or compliance of the material 18 to the surrounding brass body of the mouthpiece. That is, a-relatively thick section of material 18 is relatively, and desirably, nonbending and therefore insensitive to vibrational waves propagated or traveling through the body of the mouthpiece from one edge of the material 13 to the other.
The material 18 is mounted within a round cavity or recess 30 cut into the mouthpiece cup M adjacent the opening 27, the recess 30 being larger in all of its dimensions than the material 18. The upper surface of the material 18 is generally flush with the adjacent curved inner surface of the cup 14, and the opening 27 and the portion of the recess beneath the material 18 is filled with an electrical insulating adhesive material 32, such as an epoxy resin or the like. This adhesive material is relatively hard and thereby provides an abutment against which the material l8 can be compressed by the pressure waves developed in the mouthpiece chamber 16.
Although a resinous material like the epoxy material 32 could be used to fill the peripheral space around the piezoelectric material 18, preferably a relatively compliant or vibration damping material such as a silicone rubber material 34 is used to thereby further reduce possible transmission to the piezoelectric material 18 of any waves or vibrations traveling through the mouthpiece it) in directions generally in the plane of the material 18.
The electrode 22 and immediately adjacent area of the surface of the cup chamber 16 is covered with a relatively thin electrically conductive metal plating or coating 36 which provides the desired electrical continuity between the ground electrode 22 and the ground lead 26 without affecting the response of the material 18 to pressure waves developed within the mouthpiece 10. The coating 36 seals off the material 18 from moisture and dirt, and the coating also tends to smoothly fair together the adjacent surfaces of the installation in a manner closely simulating the smooth inner surface of the conventional mouthpiece cup.
The thickness of a typical section of the material 18 has already been briefly mentioned, but it is difficult to precisely specify the dimensions of the material 13 since this depends not only upon the particular application, but also on thesubjective tastes of the player or other'individuals concerned. However, it should be kept in mind that the material 18 should not be made so thin that it tends to vibrate in response to vibrational waves passing in directions lying generally in the plane of the material iii. This is to avoid the undesirable pickup of mechanical noises, such as valve clicking or the like.
In operation, the mouthpiece 10 is used in the conventional playing manner, whichcauses the material ld to produce electrical signals as pressure waves compress the material 18 against the mass of the resinous material 32 and the mouthpiece proper. Noises externally of the mouthpiece, and noises propagated through the mouthpiece, are not effective to compress the material 18 so that only the desired musical sounds are'converted into electrical signals for application to the circuit 2t Various modifications and changes may be made with regard to the foregoing detailed description without departing from the spirit of the invention.
ii. A mouthpiece for a musical instrument, said mouthpiece comprising: I
means having surfaces defining a partially closed chamber for development therein of pressure fluctuations corresponding to lip vibrations of the player;
transducer means having a portion located adjacent said chamber for subjection to said pressure fluctuations, said portion being deformable to provide electrical output signals corresponding to the character of its deformation, said portion being relatively highly deformable in compression compared to bending whereby said portion provides said signals responsive primarily only to said pressure fluctuations; and means adjacent said portion providing a relatively unyieldable abutment against which said portion is compressible by said pressure fluctuations.
2. A mouthpiece according to claim 1 wherein said surfaces are constituted by the inner walls of a cup-shaped chamber having a flaring outward extremity for engagement with the player's lips.
3. A mouthpiece according to claim 1 wherein said portion includes a surface mounted generally flush with certain of said surfaces defining said chamber.
4. A mouthpiece according to claim 1 wherein said portion of 'said transducer means is constituted by piezoelectric material compressible in a thickness mode in response to said pressure fluctuations.
5. A mouthpiece according to claim 3 wherein said firstrnentioned means includes a recess having edge margins defined by certain of said surfaces defining said chamber; and wherein said piezoelectric material is disposed in said recess in spaced relation to said edge margins and in spaced relation to the base of said recess; and wherein said last-mentioned means comprises first filler material filling the space between said piezoelectric material'and said base; and including second filler material filling. the space between said piezoelectric material and said edge margins.
ti. A mouthpiece according to claim 5 wherein said first filler material in said space between said piezoelectric material and said base is relatively unyieldable to afford an abutment against which said piezoelectric material is compressible by said pressure fluctuations.
7. A mouthpiece according to claim S-Wherein said second filler material in said space between said piezoelectric material and said edge margins is relatively yieldable and compliant to acoustically isolate said piezoelectric material from said surfaces defining said edge margins.
8. A mouthpiece for a musical instrument, said mouthpiece comprising:
means defining a mouthpiece cup engagcable by the lips of a player for development of pressure fluctuations in said cup corresponding to vibrations of the players lips;
a piezoelectric element located in a recess in said cup and having a face substantially flush with the adjacent surfaces of said cup for subjection of said face to said pressure fluctuations, said element being deformable to provide electrical output signals corresponding to the character of its deformation, said element being relatively highly deformable in compression compared to bending whereby said element provides said signals responsive primarily only to said pressure fluctuations; and
means adjacent said element providing a relatively unyieldable abutment against which said element is compressible by said pressure fluctuations.
9. A mouthpiece according to claim 8 wherein the edge margins and base of said recess are spaced from said element; and'wherein said lastnnentioned means comprises first material filling the space between said element and said base of said recess; and including second material filling the space between said element and said edge margins.
10. A mouthpiece according to claim 9 wherein said first material in the space between said element and the base of said recess is relatively unyicldable to afford an abutment against which said element is compressible by said pressure fluctuations.
1B. A mouthpiece according to claim 5 wherein said second ment against bending in response to any bending of said admaterial in the space between said element and said edge marjacent surfaces of said cup. gins is relatively yieldable and compliant to constrain said ele