O
`
`UIllted States Patent [19]
`Lombardi
`
`[11] Patent Number:
`[45] Date of Patent:
`
`4,899,633
`Feb. 13, 1990
`
`[54] DRUM SYNTHESIZER TRIGGERING
`APPARATUS
`
`Primary Examiner-Stanley J. Witkowski
`Attorney, Agent, or Firm-William W. Haefliger
`
`[76] Inventor: Donald G. Lombardi, 2118 E.
`Hlllcrest Dr” Thousand Oaks’ Cahf-
`91360
`[21] Appl‘ No’: 189,108
`
`[22] Filed:
`
`May 2, 1988
`
`[51] Int. Cl.4 ........................................... G10H 3/14
`U-S. Cl. ............................. ..
`
`84/DIG. 24
`[58] Field of Search ............ .. 84/ 1.04, 1.06, 1.11-1.15,
`84/DIG' 12’ DIG‘ 24'
`References Cited
`U.S. PATENT DOCUMENTS
`4,226,156 10/1980 Hyakutakc ......................... .. 84/ 1.14
`
`[56]
`
`ABSTRACT
`[57]
`A triggering apparatus for triggering an acoustic drum
`synthesizer includes
`(a) a body attachable to ‘the t'rame of an acoustic drum
`to transmit acoustic vibrations from the drum frame
`01' shell, the body con?gured to pass a drum receiver
`rod,
`G3) dual transducer Structures carried by the body to be
`responsive to the transmitted vibrations’ to produce
`signals’
`(c) and circuitry connected to the dual transducer Struck
`tures to process the signals, passing only a selected
`high frequency band of such signals to the synthe
`sum‘, to trigger same.
`
`12 Claims, 2 Drawing Sheets
`
`Yamaha Exhibit 1010 Page 1
`
`

`
`US. Patent Feb. 13,1990
`12d
`
`85
`
`Sheet 1 of 2
`
`4,899,633
`
`10
`12 2 F116- . i.
`.16’
`
`i6
`
`11a
`
`Yamaha Exhibit 1010 Page 2
`
`

`
`U.S. Patent
`
`L Feb. 13,1990
`
`Sheet 2 of2
`
`4,899,633
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`Yamaha
`
`Exhibit101O
`
`Page3
`
`Yamaha Exhibit 1010 Page 3
`
`
`
`
`

`
`1
`
`DRUM SYNTHESIZER TRIGGERING
`APPARATUS
`
`INTRODUCTION AND BRIEF DESCRIPTION
`This invention concerns an electro-mechanical as
`sembly to convert drum beats to electrical signals capa
`ble of triggering a drum synthesizer. The assembly in
`cludes a piezoelectric, self-driven acoustic transducer
`and a battery powered electonic circuit mounted in an
`enclosure especially designed to optimize the conver
`sion of drum vibration to electric signals. The enclosure
`also has a built-in lug receiver to accept drum rim fas
`tening hardware so that it replaces one of the lug receiv
`ers on a drum. The assembly mounts on the drum via
`existing holes used to fasten the lug receiver it replaces.
`These design features result in a large improvement in
`electrical performance and mechanical reliability, with
`out modi?cation of the drum shell.
`
`4,899,633
`2
`more reliable, and results in the shortest signal duration
`of the three mounting methods. It is, however, not as
`sensitive to head movement as it is to shell movement.
`The shell will vibrate with the drum head, and the sig
`nal from the shell transducer will have charcteristics
`that are undesirable for triggering purposes. The trans
`ducer used in head and shell mounting is almost always
`small a piezoelectric wafer or bar less than an inch in
`length or diameter. The transducer is often enclosed in
`a small light weight plastic or metal housing which may
`have holes for mounting screws.
`All three transducer mounting methods have similar
`disadvantages: dangling wires, unreliable mounting
`schemes and a relatively long signal duration, typically
`100.400 milliseconds. The long signal duration often
`results in unwanted re-triggering. The most common
`method of overcoming this problem is to set the sensi
`tivity threshold of the drum synthesizer to an area
`where the tail end of the transducer signal cannot cause
`re-triggering of the drum synthesizer. However, reduc
`ing the sensitivity threshold results in substantially limit
`ing the range of force of impact of a drum stick that will
`trigger the drum synthesizer. For example, a drummer
`may be forced to play in the medium soft to medium
`loud range. To maximize the range of force that the
`drum synthesizer will track, an alternate method of
`reducing the signal duration is to dampen the drum
`head. The disadvantage here is the adverse effect on the
`sound quality of the acoustic drum.
`
`5
`
`20
`
`25
`
`BACKGROUND OF THE INVENTION
`There are two main shortcomings to the current tech
`niques for using an acoustic drum to activate the sound
`programs of synthetic drum machines: tracking sensitiv
`ity and mechanical reliability. Drum synthesizers are
`designed to be triggered by a device called a “pad.”
`Pads are very different from acoustic drums in that they
`are highly damped, solid devices containing a trans
`ducer capable of detecting the force of impact of a drum
`stick. Because of its highly damped nature, the duration
`of a pad’s output signal is very short, i.e. on the order of
`4-8 milliseconds. Since a pad is solid, with no resonat
`ing chamber, it is incapable of producing any apprecia
`ble acoustic sound by itself. A drum synthesizer is de
`signed for a 4-8 millisecond trigger input to activate its
`sound output.
`In order to produce an electronic trigger signal from
`an acoustic drum, a transducer has been attached to the
`drum to detect the force of impact of a drum stick on
`the drum head. However, because of the drum’s ten
`dency to resonate after the initial impact the trigger
`output is signi?cantly longer than 4-8 milliseconds.
`Also a drum is not designed to have transducers at
`tached to it, and the current methods of attaching the
`transducer are often mechanically unreliable.
`There are three basic methods of mounting transduc
`ers on an acoustic drum: air coupling including internal
`mounting, head mounting and shell mounting.
`Air coupling consists of a transducer such as a micro
`phone that is suspended inside or outside of the drum
`50
`shell in close proximity to the drum head. This method
`picks up the vibrating air caused by the movement of
`the drum head. Internal mounting of a microphone
`often involves extensive modi?cation of the acoustic
`drum and constant monitoring to ensure mechanical
`reliability. The duration of the signal produced is very
`long, and the microphone cannot discriminate between
`drum sound and background noise.
`Head mounting usually involves gluing or taping a
`transducer to the drum head. The main disadvantage of
`60
`this technique is the damping of the natural drum sound,
`adversely affecting the acoustic characteristics of the
`drum sound. Also, the adhesive used typically cannot
`withstand the constant vibration of the drum head, and
`the transducer eventually falls off.
`In shell mounting, a transducer is glued or screwed to
`the drum shell, and the transducer can be either inside
`or outside of the drum. Shell mounting is mechanically
`
`SUMMARY OF THE INVENTION
`It is a major object of the invention to provide highly
`advantageous triggering means for triggering an acous
`tic synthesizer, and characterized as overcoming the
`above difficulties and problems. Basically, the invention
`‘ is embodied in a combination that includes:
`(a) a body having attachment means thereon for
`?rmly attaching the body to the frame of an acoustic
`drum so as to transmit acoustic vibrations from the
`shell, the body con?gured to pass a drum receiver rod,
`(b) dual transducer means carried by the body to be
`responsive to the transmitted vibration to produce cor
`responding signals,
`(c) a circuit means connected to the dual transducer
`means to process said signals, passing only a selected
`high frequency band of such signals to the synthesizer
`to trigger same.
`As will be seen the body typically contains a recess in
`which said dual tranducer means is mounted and at
`tached to the body. Also, the dual transducer means‘
`typically includes two piezo elements extending as thin
`sheets to be subjected to ?exing in response to said
`vibration transmission. Such piezo elements may com
`prise crystalline material forming said thin sheets which
`are separated and carried on a ?exible substrate.
`It is a further object of the invention to provide two
`output leads respectively connected to the two crystal
`line sheets, and a third lead connected to the substrate,
`there being a differential amplifier connected to said
`two piezo sheets via the respective two output leads, the
`ampli?er having an output side. The drum synthesizer
`then has an input side coupled to said output side of the
`differential ampli?er.
`A further object is to provide the mounting body
`with two openings for passing fasteners that attach the
`body to the drum frame, one of said openings being
`elongated and in alignment with the other of the open
`
`45
`
`55
`
`65
`
`Yamaha Exhibit 1010 Page 4
`
`

`
`4,899,633
`4
`3
`in the shell via bolts. By taking advantage of the bolt
`ings, whereby fasteners of different spacings may be
`received and passed by said openings. A drum receiver
`holes, the transducer block of the invention is mounted
`on the drum without requiring drilling of extra holes in
`rod or lug is carried by the frame and passed through a
`the shell, or use of adhesives. By including a threaded
`further opening the body or block.
`receiver in the sensor mounting ?xture, the device is
`able to replace the receiver lug. The device also has a
`means to connect the sensor’s electrical signals to the
`drum synthesizer. The connector is an integral part of
`the mounting ?xture so is extremely reliable. A battery
`is typically housed in the block to directly provide
`power to the ampli?er.
`
`10
`
`25
`
`35
`
`40
`
`COMPONENTS
`These and other objects and advantages of the inven
`tion, as well as the details of an illustrative embodiment,
`will be more fully understood from the following speci
`?cation and drawings, in which:
`
`DRAWING DESCRIPTION
`FIG. 1 is a section in elevation taken through a device
`embodying the invention, attached to a drum shell;
`FIG. 2 is an enlarged plan view showing one side of
`a dual transducer assembly used in the FIG. device;
`FIG. 3 is a section on lines 3-—3 of FIG. 2;
`FIG. 4 is an edge view taken on lines 4.4 of FIG. 2;
`FIG. 5 is a circuit block diagram, and
`FIG. 6 is a circuit block diagram.
`
`DETAILED DESCRIPTION
`In FIG. 1, a composite unit 10 includes a body 11
`including sections or block 11a and 11b ?rmly attached
`to the cylindrical outer frame 12 of a bass drum, as by
`attachment means comprising two fasteners 13 and 14.
`The attachment is such that acoustic vibrations- are
`directly transmitted from the shell to the body section
`110 i.e. at interface 15 therebetween. Such vibrations
`are also transmitted from the body section 11a to an
`annular ring 16 integral with the section 11a, and then
`to the dual transducer means or unit 17 attached to ring
`16, as by adhesive. The ring and transducer unit are
`located within a recess 37 sunk in the outer side 11a’ of
`the section 110, and as better seen in FIG. 4.
`The body 11 has two openings 18 and 19 for passing
`the two clamping fasteners 13 and 14, opening 18 being
`sized slightly larger than the shank of fastener 13, and
`opening 19 being elongated in a direction in lateral
`alignment with opening 18. Accordingly fasteners of
`different lateral spacings may be received in and passed
`by the openings, with the body 11 correspondingly
`adjusted. This compenstates for different lateral spac
`ings of the threaded openings 20 and 21 in the shell, as
`may occur for different drum shells. Thus, the unit 10 is
`attachable to different drum shells after removal of a lug
`receiver that normally attaches to the shells, as via
`fasteners extending into threaded openings 20 and 21.
`The dual transducer unit 17 is better seen in FIGS.
`2-4 as including two contact elements 22 and 23 (sepa
`rated by a uniform width gap) extending in the form of
`thin sheets (as for example of conductive metal such as
`silver) to be subjected to ?exing in response to vibration
`transmission to the frame, body, and ring 16, as de
`scribed above, when the drum head 25 is struck by a
`drum stick, or when the frame 12 is so struck (as at 120).
`The two elements 22 and 23 are separated, and carried
`on (i.e. bonded to) a piezoelectric disc 40, the underside
`of which is bonded to a flexible, conductive substrate
`170, for example a thin sheet of copper, bonded to ring
`16. The piezoelectric disc 40 may consist of barium
`
`THEORY OF OPERATION OF THE INVENTION
`A drum stick striking the surface of a drum head has
`a higher frequency content than the natural overtone
`series of a vibrating drum. Analysis of the frequency
`components of an acoustic drum shows that most of the
`resonance of a drum is of a lower frequency than the
`initial shock of impact. Moreover, the duration of the
`initial impact is short. By limiting the output of the
`transducer to these higher frequencies caused by the
`impact of a drum stick, a signal duration of 4-20 milli
`seconds is obtained. This is adequate for drum synthe
`sizer triggering. This frequency limiting or tuning is
`obtained both mechanically and electronically.
`MOUNTING THE TRANSDUCER ON A
`MASSIVE BLOCK
`By mounting the transducer on a fairly stiff substance
`such as a metallic, high density plastic or ceramic block
`or bar, high frequency vibrations are more readily trans‘
`mitted to the transducer than low frequencies. This
`block or bar is suf?ciently massive to dampen any low
`frequency vibration present in the shell in the immediate
`vicinity of the transducer. By mounting a piezoelectric
`disc on a raised metal ring of a diameter corresponding
`to the vibrational node of the disc (node support mount
`ing), a signal is produced of higher frequency and
`higher amplitude than is obtained from other mounting
`techniques.
`Electrical methods of frequency discrimination in
`clude an R-C high pass ?lter and the use of a three wire
`piezoelectric device connected to a differential ampli-=
`?er. With high pass ?ltering, the low frequency signal
`components are attenuated. A three wire piezoelectric
`device is an efficient way of eliminating lower fre
`quency components. Consider two piezoelectric de
`vices in close proximity. Vibrations that are common to
`both sensors will then produce identical electrical sig
`nals from each sensor. If the electrical signals are com
`bined differentially, as in a differential ampli?er, they
`will cancel. Signals which are different will be amplin
`?ed. The vibrations which are not common between the
`two transducers are higher in frequency with wave
`lengths that are a function of the distance between the
`sensors. For extremely high frequency (greater than 20
`KHz) a small self-driven piezoelecric acoustic element
`with two metal ink contact areas on a common substrate
`(a three wire piezoelectric device) is connected to a
`differential ampli?er. The output wavelength is there
`fore equal to the distance between metal ink areas of the
`transducer. These higher frequency components are
`only produced by the initial force of impact and not by
`the resonant ringing of the drum. The differential ampli
`?er optimizes high frequency characteristics and pro- .
`vides an output characteristic that works well with a
`drum synthesizer.
`COMBINING THE SENSOR WITH A LUG
`RECEIVER
`The acoustic drum typically has lug receivers
`mounted around the circumference of the shell that are
`used to apply tension to the drum head via lugs. A’ lug
`is a threaded rod which screws into the receiver. Lug
`receivers are attached to the drum through small holes
`
`4-5
`
`50
`
`55
`
`65
`
`Yamaha Exhibit 1010 Page 5
`
`

`
`4,899,633
`6
`drum tensioner rod carrier by the frame and pass
`ing through the body,
`(e) the body comprising a block of material within
`which said dual transducer means is concealed and
`contained, and means clamping the body against
`the frame, to receive acoustic vibrations therefrom,
`and to pass said tensioner rod, there being support
`means integral with the body, the dual transducer
`means carried in position to receive transmission of
`acoustic vibrations from the block, via said support
`means.
`2. The combination of claim 1 wherein said body
`contains a recess in which said dual transducer means is
`mounted and attached to the body.
`3. The combination of claim 1 wherein said dual
`transducer means includes two piezo elements extend
`ing as thin sheets to be subjected to ?exing in response
`to said vibration transmission.
`4. The combination of claim 3 wherein said piezo
`elements comprise crystalline material forming said thin
`sheets which are separated and carried on a ?exible
`substrate.
`5. The combination of claim 4 wherein said crystal
`line material consists of barium titanate.
`6. The combination of claim 4 including two output
`leads respectively connected to the two crystalline
`sheets, there being a differential ampli?er connected to
`said piezo sheets via the respective two inputs leads, the
`ampli?er having an output side.
`7. The combination of claim 6 including said drum
`synthesizer having an input side coupled to said output _
`side of the differential amplifier.
`, 8. The combination of claim 1 wherein said drum
`comprises a snare drum.
`9. The combination of claim 1 wherein said body has
`two openings for passing said clamping means in the
`form of fasteners that attach the body to the drum
`frame, one of said openings being elongated and in
`alignment with the other of the openings, whereby
`fasteners of different spacings may be received and
`passed by said openings.
`10. The combination of claim 9 wherein said circuit
`means is carried by said block.
`11. The combination of claim 10 wherein said dual
`transducer means includes two piezo elements extend
`ing as thin sheets to be subjected to ?exing in response
`to said vibration transmission.
`12. The combination of claim 11 including a DC
`battery power source carried by the block.
`1i
`it
`it
`*
`it
`
`5
`
`25
`
`35
`
`5
`titanate. Wires or leads 26-28 are connected with the
`thin conductive contacts 22 and 23, and with substrate
`17a, as shown, and outputs appear on leads 26 and 27,
`(lead 28 may be considered as a ground lead). One such
`transducer is produced by Murata Inc.
`FIG. 5 shows the two outputs at 26a and 27a passed
`to the input terminals of a differential ampli?er 31, and
`the output 32 of the latter is passed to the drum synthe
`sizer circuit 33. FIG. 6 shows a typical drum synthesizer
`circuit, its output at 34 passed to a speaker or speakers
`35.
`The above combination operates as set forth in the
`introduction, and has the unusual advantages, as de
`scribed, including limiting the transducer’s outputs to a
`signal duration of 4-20 milliseconds. Only a selected
`band of high frequency signals is then transmitted to the
`synthesizer, to trigger same. Note, again, in FIG. 1, that
`the circuitry at 31 may be incorporated in a solid state
`unit seen at 36, in FIG. 1, as attached to body section
`11b, as at interface 38. Therefore, the entire combina~
`tion, except for the synthesizer circuit 33 may be incor
`porated in a single unit or part 10, easily attached to the
`drum frame, as described. Snare, tom tom, or bass
`drums are usable.
`Part 10 also contains a longitudinally extending open
`ing 40 for passing a “lug” or rod 39. A series of such
`lugs, spaced about the drum are tensioned for support
`ing the drum frame. Opening 40 passes through section
`11b of the body, outwardly of the dual transducer.
`A DC battery source to power the ampli?er 31 is
`indicated at 45.
`The drum synthesizer circuit of FIG. 6 is a known
`circuit, examples of which are produced and sold by
`Dynacord Corp., Simions Corp., and Lynn Drum Corp.
`I claim:
`1. In a triggering means for triggering an acoustic
`drum synthesizer, the combination comprising:
`(a) a body having attachment means thereon for
`firmly attaching the body to the frame of an acous
`40
`tic drum so as to transmit acoustic vibrations from
`the frame, the body configured to pass a drum
`receiver rod,
`'
`(b) dual transducer means carried by the body to be
`responsive to the transmitted vibrations to produce
`corresponding signals,
`45
`(c) and circuit means connected to the dual trans
`ducer means to process said signals, passing only a
`selected high frequency band of such signals to the
`synthesizer to trigger same,
`(d) and including said acoustic drum frame to which
`said body is attached, externally of the frame, and a
`
`50
`
`55
`
`65
`
`Yamaha Exhibit 1010 Page 6