Patent Application
20080236373
The invention relates to electric musical instruments and more particularly to electric string instruments and amplifiers for their reproduction.
Cellists and other string instrument players often take the limitations of their instrument for granted. One such limitation is low sound volume, due to inefficiency of energy conversion from mechanical bowing into sound energy from a resonating cello chamber. To alleviate this problem, musicians often group multiple cellos together within a string section of an orchestra to balance off a much smaller number of individual wind instruments or brass instruments. Compared to a wind or brass instrument a cello is wimpy.
Another problem for many is the large size of the cello, making transportation difficult for small, young players. Yet another is the fact that most cellos are played by sandwiching the instrument between the legs to keep the cello steady. Those who wear a short dress or skirt may find this very uncomfortable, or worse, which further limits usability of this instrument. Still another limitation is that most cellos cannot be played while walking or marching, which inhibits use in a marching band or while sauntering around a house or restaurant.
Recent developments in electric cellos alleviate the wimpy sound problem. An electric cello produces an electric signal output that may feed headphones, or that can be amplified and output to a speaker system. See for example the Silent Cello™ from Yamaha, cellos from NS Research, Jensen, and U.S. Pat. Nos. 6,255,565 and 6,664,461. Virtually all of these cellos are held and played in the traditional manner. A few are mounted on posts above the floor and the NS Design offers a shoulder harness with a very small, 12 inch wide inflexible stomach brace that does not reasonably prevent movement sideways. Many electric cellos have strings that extend far (eg. more than 6 inches, or even more than 9 inches) below the bridge, in a throwback to the old style. Unfortunately, many or most electric cellos fail to utilize fully the technology available but use big bridges mounted on solid supports and may even use old tuning pegs.
Some electric cellos rely on digital electronics to recreate a cello like sound and use a separate, isolated pickup for each string, but tend to neglect the natural rich sound created by the bridge between the resonating chamber and the strings. Also sometimes ignored is the inter string energy transfer that occurs when vibration energy of a note from one string activates an open string that shares a harmonic or sub-harmonic relationship with the note. Such subtle interactions that give the cello its characteristic sound can be eliminated when individual isolated pickups are used for individual strings.
Developments in this area may be found in U.S. Pat. No. 6,018,120, which describes placement of a piezo electric crystal under the bass side of the bridge foot, but which still relies on a large resonating chamber; and U.S. No. 2004/0129127 A1, which purports to describe a number of “improvements” to the violin family, but which sound a little fantastic on the surface, and do not seem to be backed up with any significant experimental results. Also see U.S. No. 2002/0157523 A1, U.S. Pat. Nos. 4,389,917 and 6,803,510, which purport to present improvements to bridges and sensors located at the bridge. Electric cellos and basses are known that are held by floor stands, as seen for example in www.vectorinstruments.com/cellos/cellette.html.
Despite numerous advances in guitar and other stringed instruments over the last 75 years, many electric cellos use old technology and even maintain the unnecessary limitation of a large body, forcing the use of thumb positions. While such quaint limiting features may appeal to a small group of traditional cello players, a much larger number of would be cellists simply pass on to the more modern, more convenient and more adaptable guitar. Accordingly, cello playing is much less popular than it should be and cello music is greatly eclipsed by other instruments such as the guitar and electronic keyboards.
Other stringed instruments have related problems. For example, the electric bass guitar is considered too large by some people, and is not easily played while marching outside. This stringed instrument also is not easily bowed. A support that allows easy attachment to a player and that allows stable placement while walking around in a playing position would be an advantage and provide new opportunities for musical expression, particularly in athletic venues such as marching bands at sporting events.
Embodiments provide more convenient, easier to play stringed instruments to entice others into learning cello and to the use of other bowed stringed instruments such as the bass.
An embodiment provides a wearable cello, comprising a fingerboard, a base extending away from the user, and a stiff waist mount with a left end and a right end attached to the base, wherein the stiff mount is sized and positioned to cover at least the front of the wearer's waist with the left and right ends extending laterally. The wearable cello may have a stiff mount that is flexible enough so that a user can move the left and right ends apart by at least a noticeable distance such as 1 inch by moderate hand pressure. The stiff mount may envelope at least a 170 degrees radius, and more desirably extends straight along (and preferably curved in slightly) the user's left and right sides. The wearable cello further may comprise at least one speaker, an electric power supply and an amplifier, to allow amplification of sound from the cello within the cello. The wearable cello may comprise a speaker on a left side and a speaker on the right side, and/or a speaker in the end facing away from the player's head.
The wearable cello may comprise a chest brace positioned below the fingerboard and extending along the chest towards the user's head, away from the base. The chest brace length may be adjustable to allow for different sized cello players. The wearable cello may comprise a fingerboard and one or more piezoelectric sensors positioned between at, near or between one or more optional bridge feet and a supporting body. The wearable cello may comprise two or more humbucker type vibrating string sensors, positioned with their coil center axes non parallel to each other to accommodate curvature of the fingerboard.
In another embodiment, a wearable cello is provided that comprises a fingerboard, a base extending away from the user, and a chest brace positioned within its long axis below and parallel to the fingerboard with a strap end towards the user shoulder, away from the base, wherein the chest brace long axis is adjustable to allow for different sized cello players. The wearable cello may have a chest brace that comprises a slide mechanism that allows manual length adjustment by a sliding action. The chest brace may be removably connected to the cello by a connecter that provides chest brace adjustment via movement of the component attachment to the cello base.
Another embodiment provides an electric cello, comprising a fingerboard, a bridge with two feet and a body that holds up the bridge, further comprising soft material interposed between at least one of the bridge feet and the body, the soft material having a durometer of less than 50. The soft material may be less than ¼ inch thick and have a durometer of less than 35. The electric cello may comprise one or more piezo electric sensors located under at least one bridge foot and either above or below the soft material. Soft material may be positioned both above and below at least one piezo electric sensor. In an embodiment, a more desirable sound is produced by positioning a single sensor under the left bridge foot and over a soft low durometer (e.g. less than 40, 35, 30, 25 or even less than 20 durometer) cushion, and placing the right bridge foot over a higher durometer material than that of the left foot, for example a material having a durometer rating of more than 45 or even on a solid material such as wood, fiberglass, plastic or metal. This allows vibrational movement of the bridge to transfer energy onto the sensor via a rocking motion and replicates some aspects of natural sound.
Other embodiments and combinations of embodiments are intended and will be appreciated by a skilled reader.
The term “stringed instrument” as used herein refers to a musical instrument having one or more strings that may be plucked and or bowed to produce vibrations of different notes. The notes may be selected by pressing with one or more fingers, usually over a fingerboard that may have frets. The term “cello” as used herein refers to a bowed string instrument having a bowed string region and a fingered string region wherein the fingered string region is closer to the user's head than the bowed portion. A cello may be held between the legs in traditional fashion, attached to the floor or to a stand, held to the user's torso with a sling, strap or belt, or otherwise positioned at a relatively fixed location with respect to a user, to allow note selection by fingering. In an embodiment, the term “soprano cello” is defined to mean a 4 string cello having an E string above the A string and missing a lower C string or may include the lower C string as a 5 string cello. The term “alto cello” as defined herein means a 4 string cello having an F string below the C string and missing the A string, or may include the A string as a 5 string cello. A six string cello may include for example, both added E and F strings.
The term “marching cello size” refers to a cello with a fingerboard that is between 100.5 to 5 inches longer and particularly 1 to 4 inches longer than the 23.5 inch standard full length. The width desirably may be proportionally wider as well. An embodiment provides a bass stringed instrument for marching band use having even larger sizes and longer string lengths suited for electric bass notes. A preferred embodiment has a fingernut to bridge length of 30 inches (plus or minus 1 inch) and can use electric bass guitar strings which are designed for the short electric bass. Another embodiment is of regular electric bass guitar size and uses strings suitable for that instrument, and preferably flat wound strings.
A variety of configurations, circuits, pickups, processing, and tuning devices and systems were discovered, as described in more detail below.
In an embodiment the cello comprises a) a fingerboard with b) strings held in position over the fingerboard, c) one or more transducers that generate electrical signals in response to movement of the strings that typically are plucked (with finger/pick) or bowed, and d) either a large body held between the legs or a mount such as a shoulder mount, floor mount or belt mount to allow a fixed position with respect to the user while playing.
In a most desirable embodiment shown in
Embodiments are intended for electric stringed instruments generally. For example, although tuning systems are described in the context of their use in a cello, these similarly are intended for use in other stringed instruments as well such as electric violin, violin, bass, bass guitar, regular guitar and ukulele.
The Fingerboard The cello has at least one fingerboard with strings positioned over it so that pressing a string onto a fingerboard surface shortens the vibration length of the string and alters pitch of a note. The fingerboard may be, for example, ebony, another hardwood, a graphite composite, a metal or polymer. The string may be bowed, plucked, moved by electromechanical action, or may otherwise participate in an electronic circuit with the fingerboard to produce a signal change that may be sensed to deliver a note. In an embodiment the fingerboard, which may have frets, is reversibly attached to the cello body by for example, screws, bolts, snaps, magnets, or Velcro. In an embodiment for marching band use, the fingerboard is slightly larger than full size (e.g. 3% to 50% larger, preferably 5% to 30% larger, more preferably 10% to 20% larger in both length and width). A cello was built with regular full size string length, but having a fingerboard 15% longer and wider, and was easier to play.
A manufacturing method is provided wherein a solid base of wood or plastic, such as Douglas fir, pine, oak, fiberglass, filled or unfilled epoxy, filled or unfilled polyester or the like is covered with one or more layers of graphite-resin mixture. For example, a wood form of suitable size may be shaped into a fingerboard section and possibly one or more other sections, and then coated with resin having between 1-50%, 5-35%, 7-25% or more preferably 10-20% by weight graphite powder. The front and optionally the back of the fingerboard surface may be coated this way. Other components may be painted differently, particularly with material that contains particles that reflect light, allowing use in the sun for marching bands, where a noticeable shiny surface is desired.
In an embodiment two or more fingerboards are provided as a kit or sold with a cello having alternative features to allow change from a fretless fingerboard to a fret containing fingerboard. Another embodiment allows change to a white, black, red, blue, green, yellow, other color, or multi colored fingerboard. In an embodiment the fingerboard has two or more colors, such as the lower octave one color and a higher (closer to the bridge) octave(s) a second color. One or more frets may be added at fifth intervals. In an embodiment, a fret fingerboard is used along with a lower string such as an F string below (physically to the outside of and parallel to) the C string, to allow deeper bass accompaniment to a marching band. In a preferred embodiment a fret is provided at exactly one harmonic (mid was of the string length) for a reference point.
In an embodiment, the fingerboard is a traditional passive device having a surface upon which one or more strings are pressed to alter their effective vibration length. In another embodiment, however, that does not require a bowed sound, the fingerboard is electronically active, such that the surface has an electronic property that allows generation of an electronic signal without bowing the string and detection of string vibration. In the active fingerboard embodiment, contact of string with the fingerboard causes the generation or alteration of an electrical signal proportionate to the string length and/or to the location on the fingerboard. For example, an oscillator circuit(s) may be activated by detecting contact between fingerboard surface (and/or fret) with one or more strings. This embodiment is particularly desirable for finger practice and/or marching band use, where bowing of the string is not desired or is less practical. In an embodiment, a bow is not used, and the active fingerboard may be used for fingering practice. The same cello may be used with bowing and without bowing in an embodiment, by activation of a switch to select the mode.
A desirable embodiment provides a short bass guitar that optionally is bowable. In one such embodiment, a finger nut is used at the instrument top and a bridge is used at the bottom, that are 30 inches apart and accept 4 regular short bass guitar strings. The fingerboard optionally has frets on it. This embodiment provides electric bass guitar operation on a stable platform where preferably a stiff waist band and a chest extension allows stable attachment to the wearer's body. Such instrument can be worn while marching. Most desirably, the instrument may be plucked or even bowed, while marching, and may be used in combination with an amplifier and one or more speakers. In an experiment a regular 27 to 27.75 inch long vibrating string cello as described here was modified by adding 30 short bass strings and tuning for electric bass, with good sound quality results.
Bridge or Other String Holder In an embodiment, the strings are held in place and immobilized beyond the distal end (away from the player's head) of the fingerboard via a bridge. Preferably the bridge comprises a stiff material such as a hardwood (e.g. maple) and may be pressed onto an underlying material by pressure from the strings, as normally used in a traditional cello. In an embodiment, a bridge is used that sits on top of a non-resonating cavity and bowed strings are tensioned on top of the bridge in a traditional manner. A bow may be used to vibrate one or more strings.
Alternatively, instead of a bridge, the strings may be immobilized at each end without a bridge in between. In a desirable embodiment, a bridge is used that is of smaller weight and size than a standard maple wood 4/4 size cello to allow greater absorption of vibration energy into the bridge. For example, the bridge mass and/or volume may be (either or both) less than 0.5, 0.25, 0.15, 0.1 or even less than 0.5 times the volume or weight of a regular maple wood 4/4 cello bridge. In an embodiment the vibration energy from strings is transferred more readily to a piezoelectric transducer in contact with the smaller bridge compared to a regular bridge.
In an embodiment, improved sound was obtained by dimensioning the bridge (and optionally in combination with lesser downward string force and/or low durometer soft pad under the bridge legs) to have a good height to width ratio. The “height” in this regard means the average string height above the bridge feet. The “width” in this regard means the horizontal distance between the outer strings (maximum string separation distance parallel to the bridge feet surface). It was found that increasing the height to width ratio from less than 0.25 to between 0.5-0.66 provided a more resonating sound (sound that persists with a longer decay time). Desirably the height to width ratio is at least 0.3, more desirably at least 0.4, at least 0.5, 0.6 or at least 1.0. In an embodiment the ratio is between 0.4 to 2 and more desirably, between 0.4 to 1. In one working prototype, the bridge was about 2.1 to 2.25 inches wide and about 1.25 inches high. That bridge had a cut out space 1 inch wide and one half inch vertically in the bottom center, with a foot about one half inch horizontally (extending perpendicular to the strings) on each side. A similar bridge that was shorter gave less pleasing sound because of greater dampening. Similar bridges that were the same width but 0.5 to 1 inch higher gave superior sound. Desirably the bridge width at the bottom (feet) is narrower than the width at the bridge top, as exemplified by bridge 3 in
In a desirable embodiment bridge 10 (see
In an embodiment only one piezoelectric sensor is used, preferably on the treble string side, and in another embodiment only one soft pad is used below the piezoelectric sensor. For example, piezoelectric sensor 30 with its own pad may used with no piezoelectric sensor and no pad on the other side. A rubber, soft wood, leather, spring, or other material that allows the bridge to vibrate while alleviating absorption of vibration energy, may be used in place of pad 50 to give a brighter sound. The bridge mass may be made smaller by choosing a lower density material for the bridge, but having a greater stiffness.
Optional Mount In an embodiment, the cello body has movable or fixed arms that can be cradled and/or used between the legs, as exemplified in U.S. patents issued to Yamaha and as described and used by others previously. A preferred embodiment provides an electric cello that is worn on the torso and small enough to allow playing while standing or marching.
The preferred mount is a stiff, flexible or rigid band that is placed around at least part of the user's waist and that is attached to the bottom, distal (away from the user's head) end. The preferred mount (see top views of
Oval shape 10 of
Desirably, in an embodiment, the mount has enough flexibility so that two pounds of force placed at the middle of an extreme end with the center of the mount (normally positioned near the belly button) immobilized in a vise, acts to push that extreme end apart from the middle by at least 0.5 inch, 1 inch, and preferably at least 2 inches. In a more stiff embodiment 4 pounds of pressure (i.e. two pound on each end exerted from the center between them) are needed to push the ends apart by that distance. This flexibility allows desired snugness, which limits movement while playing.
After some experimentation, it was found that a band made from compressed cellulose ( 1/16 to 1/18 inch thick) formed in a curve and dried, and then laminated by adding one or two layers of 8-12 ounce biaxial glass cloth in epoxy, worked well. Use of one layer of 12 ounce glass on each side worked okay but two layers gave a more durable waist band. Typically, this is made in elongated curved sheets, and then sliced with a saw into 2-4 inch (preferably 3 inch) wide ribbons. After slicing, the edges preferably are sealed with epoxy, paint or other material to limit moisture entry. In one trial, regular grey ⅛ inch thick PVC sheet was cut into 3 inch wide strips and heat treated to make into a curve approximating a waist size. Two such curved strips were laminated together with PVC cement to give a stiff waist band that could accept a cello directly or via a shoe. Other plastics can of course be used, as well as combinations of materials. In an embodiment an instrument is attached directly to a flexible belt. In another embodiment, a stiff waist band is closed at the back by a strap or other elongated closing mechanism.
In another embodiment the mount includes a more flexible belt around the waist. For example, a small stiff or inflexible surface (such as for example a 1 to 25 square inch plate or plastic surface) may be attached to a belt and be attached to the cello (such as via a metal rod or other support) in the front of the user's body. In another embodiment, a costume or other larger structure may be used, such as that worn with such great flair by Marston Smith, the great, innovative new age cellist. In another embodiment the mount may be very short or missing and a belt may be relied on to attach to a user's waist.
In a desirable embodiment, the band is flexible to allow movement for doffing and donning around a waist, but stiff, such as a flexible fiberglass in a belt-shape that can be sprung apart slightly to allow tensioning around the waist sides. Best results were obtained with a band of fiberglass 3 inches high that is sized to cover the front and sides of a user's waist (
A desirable stiff waist band may have, for example, 1-8, 1-6 and preferably 2-4 layers of approximately (e.g. exactly) 6 ounce or 8 ounce glass cloth laminated in the shape of a “U” with side distance 40 between 1 to 14 inches long especially preferred. Experiments using epoxy and 8 ounce glass fiber over thin ca. ⅛ inch thick particle board showed that 3-4 layer of glass gave best results. A plastic such as PVC may be used. For example, two ⅛ inch thick 3 inch wide bent strips of PVC may be solvent welded together to form a flexible band that will keep its shape while worn on the waist with a cello mounted (preferably through an intervening shoe) on the front.
Most preferred was a band with a slight curvature (e.g. 5-30 degrees of the body radius on each side) inwards of the side distance 40, as this allowed snug placement on the body. The band may be assembled as 2 or more sections that can be snapped, bolted, velcroed, or otherwise connected. The band and its connection to the cello most preferably should be stiff enough to allow the cello to sit upright when placed on the floor, with the keyboard at a natural looking playing angle as depicted in
In an embodiment, the mount additionally has a flexible band such as a belt, (made from rubber, leather, plastic, fabric or other material) that connects two ends of the mount. A two inch wide leather belt was found to work best. Preferably this shoulder strap connects from the right side (position 50 for example) to (preferably the top of) a fixed or adjustable chest extension on the cello as described below. In another embodiment the mount is snapped, velcroed, buttoned or otherwise attached to a shirt, vest, coat or other worn clothing of the user.
Desirably the band at or near (preferably within 8, 6, 4, 3, 2, of 1 inch) its center at position 20 is attached to the cello at the lower half and preferably at 1 to 12 inches from the distal (bottom) end of the cello, away from the players head. The band at or near position 50 (i.e. on the side) preferably is connected to a chest extension or to the cello top by a strap, such as a leather or cloth strap, with the strap extending over a shoulder as for an electric guitar.
Desirably, the mount further is attached to the cello body via an intervening spacer termed herein, the “shoe.” A shoe may be as small as a wooden wedge spacer less than 3 inches deep that connects the cello at a preferred angle (with stringed top tilted to the wearer's right side, for example) to the mount. In a series of tests, ⅛th inch thick aluminum strips 2 to 3 inches wide were bent into a shoe shape as depicted in
In an embodiment, batteries and an amplifier are placed within the shoe cavity, and the shoe further contains a jack on side 840 to connect a speaker. In another embodiment a speaker further is added on one or both open ends formed by sides 810, 820, 840 and 850. A ten watt amplifier, 5.5 inch diameter speaker, and twelve AA side metal hydride batteries were installed in a larger shoe having the same ratio of sides but large enough for a 5 inch speaker. This system gave strong sound with the speaker but caused strings and other parts to resonate at high levels. For marching band use, it is more preferred to use an outboard speaker that may be attached via an absorbent material (e.g. rubber or neoprene) or more likely simply attached to a different part of the player's body. In a particularly desirable embodiment, a tubular speaker is inserted into a larger shoe. In a preferred embodiment, a 6 inch diameter 12-16 inch long circular tube is inserted into a shoe made from 3 inch wide aluminum and just big enough to hold the tube, and a 6 inch diameter speaker and amplifier/batteries also placed in this speaker cabinet.
In an embodiment not limited to use with electric stringed instruments, a speaker/ amplifier contains a closed cavity (no ventilation) that includes at least one audio amplifier and at least one speaker driver. A problem with active speakers is the need to expel waste heat outside the cabinet. A solution was discovered accidentally while making large, sealed, bass speaker enclosures. It was noticed that including a small hole in the cabinet resulted in a big rush of air out (and back in) during strong bass notes, without perceptively decreasing the amount of bass sound. In this context,, it is noted that decreasing a (for example) 10 watt acoustic power output signal by 1 watt causes less than 1 decibel decline in power. Assuming that the removal of power (via expelling air in a small hole) is constant over the usable frequency range, there is no appreciable qualitative difference in the resulting sound. Accordingly, it was discovered that a one way air valve could be made from such hole in the cabinet. By providing two holes, one on each side of a heat emitter (e.g. amplifier) located within the sealed cabinet, a breeze of outside air can be flowed past the internal heater, removing heat, especially during loud play of bass notes.
A one way air valve can be made by a large variety of methods and preferably does not clatter during use. Accordingly, a soft material such as rubber may be used to cover an opening in the cabinet and attached at one side, to allow opening when pressure differences exist. For example, a hole on a left side may have a flapper on the inside, so that high pressure inside forces the flapper to obstruct the hold, but low pressure on the inside causes the flapper to open and outside air to enter. Meanwhile, a hold on the right side may have a flapper on the outside surface so that high pressure inside causes air to exit, but low pressure inside causes air to rush in from outside. In practice, the flapper and holes are covered or recessed to protect them. A screen may be used to cover a recessed hole and flapper. Two, three, four or even more one way valves may be located virtually anywhere and the moving air can be channeled to flow where needed on the inside. In an embodiment, the flapper or a connector that affects tension on the flapper may be a bimetal strip or other material that changes the flapper performance with changes in temperature. For example, a flapper can be loosed up (allowed to open/close) upon a bimetal strip responding to increased temperature inside the cabinet, and allowing air flow during speaker cone movement. In an embodiment, a semiconductor is attached to a finned heat sink inside a sealed cabinet, and two or more one way valves as described here are positioned and coordinated to allow air movement from outside and through the heat sink, especially during loud bass note reproduction, when such cooling is needed the most. This allows the designer to avoid having to put heat sink(s) such as fins or metal parts, on the exterior of a cabinet, and to avoid using an active fan with associated power supply.
For greater player comfort, a wedge was used to connect shoes to the cello bottom. In one most desirable embodiment, a wedge from 0 inches on one (lateral, extending down the cello long axis) side to 1 inch (lateral) thick on the other side was placed between 3 inch wide shoes and (ca. 2.5 inches varying) cello bottoms, to turn the cello string top to the players right side. A shoe (with or without added wedge) typically may be between 0 and 15 inches between the waist band and the cello, more preferably between 0 and 8 inches and yet more preferably between 1 inch and 9 inches. In another embodiment, no shoe is used and the cello is attached directly to a user's belt or to the mount.
Chest extension brace 520 is not exactly parallel to the long body axis of cello 500 but has a top end (with strap 550 attached) that is between 0.5 to 2.5 inches and more preferably 0.75 to 1.5 inches) offset to the right side of fingerboard 560. While shoe 510 is aligned with the instrument long axis (represented by the axis of fingerboard 570), adapter wedge 505 tilts the fingerboard clockwise (looking down the long axis from the head end) by at least 5 degrees, more preferably at least 15 degrees and yet more preferably at least 30 degrees. It was found that attaching the adapter 505 and shoe 510 to the left side (about 0.5-6 inches left, preferably 1-3 inches left as viewed by the player wearing the instrument) of the waist band center, and providing a 30-75 degree rotation of the cello, gave a good, natural wearing cello feel.
Optional Chest Extension As exemplified in
Preferably the chest extension is within 30 degrees of being parallel to the fingerboard. In an embodiment the chest extension is within 10 percent of being parallel with the fingerboard. That is, the top point of the strap mount (if used) and the bottom attachment point to the cello body forms a line that is not parallel to the fingerboard, but somewhat away from being parallel to accommodate the need to position the cello top on one side of the neck. Desirably, the chest extension is positioned to be more vertical than the fingerboard during use. In a preferred embodiment the chest extension top is closer to the finger board than is the chest extension bottom, to thereby allow the fingerboard to slant more towards the user's neck.
Chest extension 310 in an embodiment is shorter than fingerboard 340 and preferably is between 1-20 inches, 2-10 inches, or even 3-8 inches shorter than the fingerboard when fully extended. An adjustable chest extension adjustable was found advantageous because the height of a strap mounted to the extension affected playing comfort. By sliding, remounting (with a fastener such as a screw, wingnut, magnetic latch, clamp or the like) or otherwise adjusting chest extension 310 to extend different lengths (exemplified as dotted line 320) shoulder pressure was alleviated. A taller player, for example, will want to extend the chest extension longer than a shorter player, so that any optional strap attached at 330 will exert less undesirable force on the body during prolonged use. In an embodiment, chest extension 310 is adjusted so that mount point 330 is between 0 and 3 inches from the top of the shoulder.
In an embodiment the chest extension may exist as two or more parts as will be appreciated by a skilled artisan, who may for example build this with parallel rails or with two or more telescoping pieces. In an embodiment one or more electronic controls are provided in or on the chest extension. Any control, rotary, sliding, touch sensitive, toggle, or otherwise, used for any purpose such as audio volume, stereo/mono switching, degree of reverb, depth of reverb, reverb time, equalization, bass boost, tremulo, on/off switching, radio output switching/.frequency, reference tone output for tuning, and the like may be used in this regard. Desirably the chest extension comprises an elongated section of wood and the wood contains a sliding control for volume or for controlling reverb or other parameter, wherein the sliding control can be physically moved at least 1 inch, 1.5 inches, 2 inches, 2.5 inches, 3 inches or more by the user's thumb while playing.
While discussed in the context of a cello, this disclosure and particularly the following description applies to other stringed instruments such as violin, viola, bass, banjo, and guitar.
Transducers An electric cello in many embodiments uses one or more sensors to convert vibrations that originate with the strings into electronic signals that optionally may be processed and amplified to produce music.
An embodiment provides new and improved transducers. Piezo electric transducer systems were explored that provide improved sound and sound systems.
1). Piezo electric sensors are preferred in many embodiments. Most preferred are organic material based (often polymeric) sensors, such as those sold by Measurement Specialties Inc., a Pennsylvania company. Certain piezoelectric materials are particularly well suited that comprise polymers which can be cast in the form of plastic sheets or other forms and make particularly good, linear response sensors. Particularly, polymers known as PVDF (poly vinylidene fluoride) polymers are contemplated. The term “PVDF polymer” means either the PVDF polymer by itself and/or various copolymers comprising PVDF and other polymers, e.g., a copolymer referred to as P(VDF-TrFE) and comprising PVDF and PTrFE (poly trifluoroethylene). In an embodiment, a polymeric sensor is chemically bonded to a soft material such as a rubber, neoprene, or other foam.
In a desirable embodiment one or more flat piezo electric sensors are positioned under one or more parts of the bridge such as under the feet of the bridge as shown in
In an embodiment two piezo sensors are used on opposite sides of the bridge in phase, and common mode signals are rejected for improved noise performance. In another embodiment acoustic modulation is used to produce sound multiplexing with two or more sound transducers and at least one amplifier. One transducer may be used to generate an acoustic signal that is amplified and turned into a vibration by the other transducer. The amplified piezo desirably is time delayed signal and preferably is controlled for undesirably (squealing) uncontrolled feedback.
In a most desirable embodiment sensors 20 and 30 feed two channels of an audio amplifier to generate a stereo sound. The stereo sound may be further developed by adding phase shift, or slight delay (5-35 ms) to one side and by changing equalization and/or phase shift between both sides, using software, hardware, or a chip such as the Philips TDA3810 or Toshiba TA1343N.
2. induction coil pickup(s) are preferred in some embodiments. An embodiment provides an induction coil (i.e. “humbucker”) that is similar to that used in the electric guitar, having a wire wound around a metal wherein the metal is a magnet or is near a magnet and directs a magnetic field through the metal. An embodiment provides rare earth magnets for greater sensitivity and in some cases, greater immunity to noise. Another embodiment provides a wire wound around a magnet or paramagnetic or ferrous material. Desirably the coil is connected to a low impedance (i.e. less than 100,000 ohms, preferably less than 10,000 ohms, more preferably less than 3,000 ohms and even more preferably less than 1000 ohms. Preferably two or more induction coil pickups are used. In an embodiment, each coil is located equidistantly from two strings (such as the A and D strings; or G and C strings) and in another embodiment one coil is located under each string. In an embodiment, each coil is positioned in a different plane with respect to the others, but the center axis of the coil is perpendicular to the long axes of one or more strings. In another embodiment, pairs of coils are positioned for each string or string pair, and out of plane with respect to other coil pairs.
The outputs of pairs of coils may be compared via a circuit for common mode rejection, to reject at least some common mode noise such as 60 hertz hum that may be picked up by the coils. A skilled artisan with an understanding of humbucker technology used in electric guitars readily will appreciate how to connect two or more coils and process their signals to minimize hum. In an embodiment, the output signal from each coil is separately amplified, with separate gain adjusts, to allow loudness adjustment among the strings, or string pairs. For example, a coil sensor next to the C string may be more sensitive to the vibration of the larger mass of the C string, as compared with the smaller mass of the A string. Separate control amplification of signal intensity allows compensation for this effect.
Enhance Resonance
Some electric cellos sound dead before digital processing of the sensed signals. in some cases this is because an old fashioned style of wood bridge is tensioned on top of a solid body, which quickly dampens the cello string vibration sound. In other cases, the strings are held by a plastic or metal positioner, which absorbs string energy more readily than a traditional cello. Furthermore, some electric cellos dispense with a bridge altogether, and lack the inter-string energy transfer that gives the cello some of its melodious tone. Embodiments of the invention enhance resonance passively. Some embodiments enhance resonance actively, as reviewed next.
Passive Devices to Prolong String Vibration Decay Times An embodiment alleviates the problem of string vibration quenching by providing a smaller bridge that absorbs less string energy in order to vibrate. In an embodiment, the bridge is positioned by string tension on top of one, preferably two, or more soft pads to facilitate bridge movement and allow longer string vibration decay times. Another embodiment provides a low friction surface under the bridge to facilitate longer vibration decay times. Another embodiment provides a lighter weight yet stiffer bridge material such as fiberglass to improve resonance. Yet another embodiment provides less string tension to prolong vibration decay time. Desirably 2 or more of these embodiments are combined for enhanced sound quality.
A bridge, if used, desirably should be less than 15 gm, 12 gm, 10 gm, 7 gm, 5 gm, 4 gm, 3 gm, 2.5 gm, 2 gm, 1.5 gm or even less than 1 gm in mass. Without wishing to be bound by any one theory of this embodiment of the invention, it is believed that the smaller weight requires less energy to obtain vibration in the weight. Desirably the bridge is at least 30%, 50%, 75%, 80% or more lighter in weight than a traditional cello bridge, or the bridge used by the Yamaha Silent Cello™. Preferably the bridge has two feet in the traditional sense, with one foot at one end and one at the other, with an axis between them that roughly is perpendicular to the strings.
The bridge desirably is tensioned on top of at least one soft pad. Preferably one or more individual soft pads are located under each foot of the bridge as shown in
In experiments, it was surprisingly found that a bridge mounted on soft pads yielded dead notes (relative inability to resonate the bridge with the strings). This was found more often for the middle string on a 5 stringed cello and was associated with strings that were not placed evenly on the bridge. It was found that using a higher durometer material (such as rubber or a spring) under the higher pitched note bridge foot, which has greater tension (eg. A string of cello), compared to softer durometer material under the less tensioned bridge foot (eg. C string of cello) yielded better sound. Preferably the durometer difference is at least 5.
The bridge preferably is stiff. In an embodiment, a hardwood such as maple is used. In another embodiment fiberglass is used. Fiberglass may employ a variety of glasses and polymer. Although epoxy is easier to use, polyester is more preferred due to its greater stiffness. Carbon fiber is preferred over glass fiber due to its greater stiffness.
Interharmonic Part of the richness found in the cello sound arises from interharmonic modulation, wherein, for example, two vibrations combine to produce additional vibrations of different frequencies corresponding to their sum, differences and products. Embodiments of the invention provide two types of modulation to lend an electric stringed instrument this characteristic. One, the modulation can occur via mechanical vibrations interacting and two, the modulation can occur electronically.
Mechanical modulation according to an embodiment occurs when an output device such as a loudspeaker or piezo crystal driven by a circuit feeds back acoustic energy to a pickup device such as a piezo electric crystal, wound coil or microphone.
Electronic modulation according to an embodiment occurs in hardware. An example of hardware based modulation is the introduction of two or more signals into one or more diodes or other non-linear devices. Electronics artisans, particularly in the RF radio transmission and reception field are long familiar with such devices. In the audio realm, a ring modulator, either balanced, or unbalanced, often has been used. A balanced ring modulator for example, generates sidebands (addition, subtraction and multiplication modulated signals from two source signals). Such modulation can generate a composite signal that lacks the original input (i.e. less than 10%, 2%, 1%, 0.3%, 0.1% or even less of the original) signals in the total power output. Such modulation output can be added back to a signal to add richness to that signal. In a particularly desirable embodiment, a source audio signal is processed into a delay and the delayed signal is combined, or “mixed” with the original in a modulator, to produce sidebands. In yet another embodiment, a pure sine wave, or series of harmonics such as from a square wave, sawtooth wave, or other shaped wave, is input into the mixer, and an audio sensed signal from the cello is also added, to produce sidebands.
In an embodiment, the ability to inject for example, a sine wave or series of sine waves corresponding to a note allows a melodic theme by choosing the key of a song to be played, and providing a corresponding note of that key (eg. a C note for a song played in the key of C) to input into the modulator for forming side bands. In another embodiment, one or more notes such as the A, D, G and C note(s) that correspond to individual string(s) may be presented to a modulator and mixed with a detected signal to provide modulated feedback for string tuning and to liven up a performance. For example a sine wave or set of harmonics corresponding to a C note is entered into a ring modulator and a cello acoustic signal is entered into the same ring modulator. When a song is played in the key of C, notes are compared with C and an output (sum, difference, product) from the ring modulator are output. This ring modulator output may be blended with the cello acoustic signal to create a rich composite. The ring output in an embodiment is less than 20%, 10%, 5%, 20% or even less than 1% of the rms composite signal strength.
Stereo Cello An embodiment provides stereo cello by sending at least some of a signal from the left sensor of a cello bridge to a first channel and at least some signal from the right sensor of a cello bridge to a second channel. Experimentally it was found that, especially for hardwood bridges that attenuate vibration from one side of the bridge to the other, such stereo separation or partial separation provides an enjoyable separation in space of notes played from one side of the cello to the other. Most desirably a thin piezoelectric pickup is positioned under each bridge foot. In an embodiment at least two amplifiers are used to process signals from at least two sensors to provide such dimension, which can be enjoyed by stereo headphones, or by a stereo amplifier and speakers. Further analog and or digital enhancement may be obtained with a stereo enhancer chip or software as is known to skilled artisans. In another embodiment, one sensor under one bridge foot (or a sensor located elsewhere) is used to generate a signal output, and a piezoelectric transducer is located under a bridge foot (or the other foot) to produce feedback. Desirably, the input signal to the feedback transducer is driven by an echo (delay circuit) and can in some instances more faithfully emulate the sound of a natural old fashioned cello.
Two or more output channels can be used to present differing echo signals. For example, audio signal from a sensor can output to a first channel and the same audio signal after reverberation (echo) processing can be output (or simply mixed into) a second channel. In an embodiment, two different echo signals are used. A first echo signal with a first delay time is made from one type of signal, such as from a first sensor at the bass side of the cello, or from lower frequency filtered signal. A second echo signal with a second delay time is made from a second type of signal, such as from a second sensor at the treble (A-string side) of the cello, or from a higher frequency filtered signal. These two echo signals may be further mixed and/or output into two channels. In a desirable embodiment, a first reverb circuit with less high frequency attenuation is used for a shorter echo time (e.g. 10-100 msec) for a treble or higher frequency signal, and a second reverb circuit with more high frequency attenuation is used for a longer time (e.g. 75-250 msec) for a bass or lower frequency signal. For example, signal from a pickup on the treble (A string side) foot of a bridge may be processed for shorter echo and less high frequency filtering while a signal from the bass (C string side) foot of the bridge may be processed for longer echo and more high frequency filtering. By providing two or more types (delay characteristics) of echo, particularly matched to pitch, a more natural echo can be recreated.
In an embodiment, the tonal quality of the stereo cello is enhanced by increasing the low bass (response maximum between 30 and 200 hertz) for the C string side pickup more than for the A string side pickup. In another embodiment enhanced special response is obtained by use of the TDA3810 chip, use of comb filters as is known to skilled artisans, or other circuit or software that provides enhanced stereo signals.
Reverb Generation, Control Desirably electronic reverb is added at the cello or outside the cello. A high speed sampler that stores audio signal information into an array and then reads out the information may, for example be used. The reverb time preferably is between 0 and 2 seconds and more preferably between 0.02 and 0.5 seconds. The time of delay and proportion of delayed signal with undelayed signal may be adjusted. In a particularly desirable embodiment reverb is added to two channels of a stereo cello (or other stringed instrument such as a violin). The instrument player may adjust the reverb during play by manipulating a control on the cello or by a foot pedal.
In a particularly desirable embodiment the amount of delay, (delay time, or amount of delayed signal or both, but preferably delay time) is adjusted by a foot pedal. Desirably the foot pedal is attached to a control, such as a linear taper potentiometer, allowing the user to continuously adjust the degree of reverb. This allows the user to play music at little or no reverb, but then slowly add reverb, or even suddenly add a longer amount of reverb to the very end of a piece of music, to give a special effect of a final, long echo. Accordingly, one embodiment contemplated is a stringed musical instrument system comprising a stringed instrument and attached/attachable continuously adjustable reverb foot pedal. Desirably, the foot switch allows a movement of at least ½ inch, at least ¾ inch, at least 1, 1.5 or even at least 2 inches of vertical movement associated with delay time and/or amount of delay signal. In an embodiment the foot switch itself contains a single or dual gang (for stereo) potentiometer and the reverb circuitry may be placed with the footswitch box.
Training wheels for the player. A desirable embodiment provides enhanced output for correct or desirable notes, while dampening, ignoring or enhancing less, undesirable notes. This selective enhancement can provide guidance feedback to the player and particularly the inexperienced player, who may have trouble hitting the correct notes. Most desirably, an enhanced output provides selectivity for one or more notes of a scale and a note played off that scale which is not an enhanced note will result in less audio output volume compared to a selected note. In an embodiment, 4, 5, 6, 7, 8 or more notes of a scale are enhanced this way. Enhancement may be carried out mechanically via one or more tuned resonance systems coupled to the system, or more preferably, electronically, via digital or analog circuit processing that enhances selected notes.
In a mechanical embodiment, extra string(s) are used as tuned resonance systems. For example, 2, 3, 4 or more passive strings may be tensioned to resonate to one or more notes on the selected scale. These may be physically attached to a bridge so that bridge vibration is transmitted to these extra string(s). By way of example, a standard cello with A, D, G and C strings attached to a cello may contain other passive string(s) tuned to B, E, and/or F (or less desirably, additional string(s) tuned to A, D, G and/or C). When a player of such system hits a B note and a passive B note resonating string is used, the B note resonates longer and provides more audio presence. In contrast, a B flat note would not excite the passive string system. In this way, the passive strings provide improved sound and discriminate against undesired notes.
In an electronic embodiment, selective enhancement of notes (optionally including, for example, their fundamental frequencies plus harmonics) is carried out by computer or by hardware. A skilled artisan can design or build circuitry that preferentially responds to desirable notes of a scale. The electronic audio signal from the stringed instrument (such as electric cello, violin or bass) may be processed, for example, by multiple active filters, each tuned to a note. The outputs of the active filters may be mixed to produce a composite signal.
Computer processing is particularly desirable for obtaining selective enhancement. Typically, a scale is selected and software is instructed to emphasize correct notes. The emphasis of correct notes, in both hardware and software systems, may be set to or adjusted to different qualities. Most preferably, the selectivity (or width of acceptable note frequency) may be narrow or wider, and the degree of selective enhancement may differ. For example, each note may have a narrow acceptable frequency range of plus and minus less than 1, 2, 3, 5, 7, 8, 10, 12, 15 or up to 20 hertz, with respect to the frequency of the lowest, or fundamental frequency of a note. An arbitrary measurement in this regard is the location of a 3 db cut off on either side of a center frequency of the note. For example an A note of fundamental frequency 440 may have a plus or minus 2 hertz “selective enhancement region” wherein signals within 438 to 442 hertz are emphasized by an average (weighted evenly within this interval) of at least 3 db with respect to signals immediately outside this narrow band pass. Most desirably, the overtones (2nd, 3rd, 4th, 5th etc. harmonics) associated with the note (876 hertz to 884 hertz) also are emphasized with respect to their adjacent frequencies. In practice, “emphasis” may be measured by taking an average of the emphasized range (438 through 442 in this example) and comparing to other ranges immediately outside the selected range.
An embodiment provides a string instrument such as a cello, violin or fretless guitar wherein desired notes of a scale are selectively enhanced. Most desirably, the notes are associated with a particular scale that the user may select, and the degree of enhancement also is selectable. In this way, a new student may more quickly become familiar with the scale and the correct placement of fingers to obtain a correct note of that scale.
In a particularly desirable embodiment, one or more computer chips such as a microprocessor are used to emphasize correct note (desirable notes such as the notes of a desired scale, and not off-notes) frequencies over incorrect note frequencies. Such digital processing may be used in a wide variety of stringed instruments, particularly those that lack frets, such as fretless bass guitars, cellos, violas and violins. Circuits, software and instruments that have these features are contemplated and can for example allow a player to play correct notes more easily without frets.
Most desirably the degree of discrimination of correct note frequencies is selected by a switch or control knob. In one such embodiment, an electrical signal from a plucked or bowed string is input into an analog to digital converter at a rate of at least 5,000 hertz, 10,000 hertz, 15,000 hertz, 19,000 hertz, 25,000 hertz, or at least 40,000 hertz. Digitized output then is processed by one or more microprocessor-computers. In one embodiment, fourier transform is used to generate a value or set of values corresponding to a given note and then compared with stored values. In one type of comparison, if the comparison indicates that the note is very close to or identical with a desired note (such as the given notes for a particular scale or scales) then the note is not attenuated, or may be enhanced. On the other hand, if the result of the comparison indicates that the note is off key, then the note is attenuated, not amplified as much as an on key note, or maybe ignored (is not processed further into a sound), After such manipulation(s) the digital signal(s) corresponding to the note are converted back into a larger signal that can be converted into sound, by an amplifier and loudspeaker, for example.
In another embodiment, after comparison of the digitized signal with a reference (acceptable reference notes from a scale for example) a note that is found to be slightly off key is adjusted up or down into correct key. Use of fourier transformed representations of sound are particularly useful for this embodiment, because the mathematical representation of the note can be adjusted mathematically into key.
In an embodiment a signal such as a light, sound, mechanical vibration shaking, or even an electrical shock is presented to the player to alert the player of the presence and/or degree of the mistake in the played note. In an embodiment, a user can select a desirable scale by a switch or other signaling device. The degree of correction also may be adjusted, as will be appreciated by a skilled artisan. The embodiments of electronic note comparisons and adjustments as reviewed here are particularly useful for fretless bass guitars, where often one note at a time is played. In another embodiment, the notes are adjusted to become off key by computer manipulation. In yet another embodiment, the notes of one key are transposed to notes of another key, as selected by the player.
Modern electronics may be used to enhance the musical experience. In one embodiment a headphone jack is provided at the top (proximal) end of the cello, to provide easy access to headphones where most needed (by the user's head). Desirably, the headphone jack is located facing the user (on the right side or edge of the cello top part) so that accidental pulling away of the cello from the user's head would allow removal of the jack in the direction of movement instead of possible bending or stress on the wires, that would occur if the jack were behind the instrument. In another embodiment a microphone is provided at the top of the cello on a holder that can be positioned or bent towards the user's mouth. In this case, the microphone output optionally may be transmitted from the cello to a receiver, and then amplified.
Cello Training Systems In a desirable embodiment a cello (or other instrument: cello is used as an example) training system is provided wherein a music book or file (electronic file and/or paper) is provided along with music and/or optional video or audio instruction. The instruction preferably is from the internet and is downleaded directly or indirectly into the cello or accessory to the cello (such as a memory stick that transfers to the cello). An embodiment further provides an LCD visual output attached to the cello, allowing instructions to be displayed while wearing the cello. Music score display for marching band use also may be displayed this way and input from the internet or other source. A system may for example comprise an audiovisual interface that is built into the cello or attachable to it (as an accessory) and a device or system for inputting software.
The device or method may be a memory stick, which accepts information from a computer, a compact disc, or other storage device. A system may also provide an access code for obtaining information from a web site. In an embodiment, a student obtains a lesson from the internet, the inputted lesson is displayed on the cello (or is activated by a switch), and the cello senses the quality of the student playing, such as monitoring correct bow movement, correct tone creation and rhythm. This information is stored and may be reviewed by the student or even sent to a remote teacher for individual or mutual review. Of course, individual or subcombinations of components as described here may be employed.
Correct bowing is very important to stringed instruments and an electronic feedback system is provided to assist learning the proper technique. In one embodiment the perpendicular placement of a bow to the fingerboard axis is monitored and a correction signal output to the user. This system, in its more basic conformation includes a first sensory monitor of perpendicularity and a second output device. A sensory monitor may for example continuously monitor the fingerboard axis with one, or (preferably two or more) tilt sensors, one or more magnetic sensors or other sensors as a skilled engineer readily will appreciate. The bow position itself is monitored, either by sensors on the bow, which output a suitable signal(s) for comparison, or by monitoring indirectly.
In the latter instance, the bow desirably includes one or more magnets or ferromagnetic material, to be detected magnetically by sensors on the stringed instrument, or may be detected optically by optical probing of markers on the bow. Preferably the bow contains resonance or inductive resonance bodies, such as those used for card key systems, and the stringed instrument emits probing signals that return reflective or induced signals from the bow commensurate with proximity. In an embodiment two or more sensor types (using two or more frequencies or frequency sets) are used to probe and obtain information from at least two dimensions or points of bow position. This system may be used to determine: 1) how perpendicular the bow is to the strings (compare with fingerboard or string axis); 2) how close the bow is to the fingerboard; 3) timing; and/or 4) how flat the bow hair surface is on the strings. A skilled engineer can derive suitable sensors, receivers, and comparison software for determining correction signals.
Correction signals may be output to the user a variety of ways. Optical feedback may occur by flashing or colored lights, or an LCD panel for example. Tactile feedback may occur by differential weighting of the bow (via magnets, or other means) electromechanical adjustment of a weight in the cello, or a vibrator for example. Audio feedback may occur via a buzzer, speaker, or voice comment from a speaker for example. In another embodiment the degree and or frequency of correct or incorrect placement of the bow is monitored and this information is stored for later review by a teacher. Such information may be input and sent through the internet to a long distance teacher for review, and may be graphed or charted to show the student's progress.
The stringed instrument may monitor the tonal accuracy and/or rhythm of music or other sounds played. In an embodiment, a reference set of sounds, such as a melody or practice bowings is selected, and the student plays the selected piece. The stringed instrument monitors the frequencies of the played music and compares with the selected (stored) optimum frequencies, and outputs (stores) a set of values corresponding to the deviations from the stored values. These deviations are output to the player and or to a teacher in a similar manner as described above for bow correction. In a very basic implementation of this embodiment, the student plays a single note and the instrument listens and directly feeds back a correction signal.
On Board and/or Attachable Speakers In an embodiment the electronic output may be converted to sound vibrations in or on the cello itself, via one or more small speaker(s) in the lower unit, or else, worn elsewhere on the player's body. In an embodiment, at least one or two sensor outputs are optionally processed and then amplified by one or two audio amplifiers of at least 2, 5, 10, 20, 25, or even more watts per channel RMS output. The output preferably is sent to small speaker(s) in the cello itself, preferably 3-4 inches diameter or larger. In an embodiment, a rectangular or small 3-5 inch diameter speaker is positioned on the right side of the cello and a small speaker is positioned on the left side of the cello, both facing out and within an air tight chamber. In an embodiment, improved bass response is obtained by driving two or more speakers that share the same acoustic chamber with a common signal (either exact same signal or same bass component in different signals). By moving the speaker cone if the same direction simultaneously, a lower bass response is obtained.
In another embodiment, a speaker is reversibly attached at the bottom end of the cello, and preferably by attachment to the user side of the chest brace (if present). In an embodiment, a vibration isolation material, such as a layer of rubber, neoprene, or other plastic is interposed between the speaker and the instrument. In an embodiment the speaker is attached reversibly by magnet(s) located in the speaker and/or in the instrument. Another embodiment provides a cello case having its own electric power supply, speakers and amplifier. This allows the user to plug in (or use radio transmission or IR light transmission) signal from the wearable cello to the cello case, which provides sound.
Experiments were carried out with small amplifiers (1 to 10 watts RMS) and a variety of speakers. Results indicated that small speakers could work well in the cello body itself, placing a speaker in an optional shoe worked better, but using a large speaker in a large cavity not attached to the cello directly, worked best. The best sound came from placing a larger (6 inch diameter or 6×9 oval) speaker in or adapted to large tubing. Most preferred for marching band use is an elongated/folded tube speaker cabinet that can be worn (for example on the back) and having one or two speakers at the end(s). A six inch inside diameter tube can be folded with total length of at least 1.5 feet, and preferably at least 2 feet, 2.5 feet, 3 feet or more for good sound. Batteries and amplifier may be placed inside the enclosure or preferably attached to the outside.
In an embodiment, an independent music source such as an iPOD or other electronic music playback device outputs into the cello to allow the cellist to play “cello karaoke” along with the recorded music. Preferably the cello has, such as on its lower half, and preferably at the optional chest brace, an attachment such as a magnet, clip, Velcro or other fastener to allow easy storage of and use of the playback device while wearing the cello.
An embodiment provides one or more built in reference tones for tuning. Desirably a 220 Hz, or 440 Hz sine wave or complex (such as square wave) signal with a fundamental tone at this frequency is used. Additional tones corresponding to each string also may be included. The sound may be manually switched and/or may be automatically switched. For example, a timer in the cello can sense if at least: 1) a significant temperature change has occurred that might be expected to alter string tension (more than 1, 2, 3, 4, 5, 7, 10, or more than 15 degrees Fahrenheit for example); 2) a long time (e.g. a day, two days, week or more) has elapsed since the cello has been turned on; and/or 3) string tension has changed since the last time the cello was on, or over a given time period.
An embodiment provides a heated fingerboard. This is particularly useful for marching band use in the winter. The fingerboard may be heated via use of conductive graphite and impressing a low voltage (preferably less than 50 volts, more preferably less than 36 volts, 12 volts, 5 volts, and even more preferably less than 2 volts) through the graphite. For example, a DC voltage may be impressed from the bottom of a graphite surface or solid to the top. A battery that has preferably between 1 and 200 watt hours, more preferably between 5 and 25 watt hours of energy may be used to generate heat at a 0.5 to 50 watt and more preferably 1 to 10 watt rate over that surface or solid.
Water resistant bowing components and systems also are provided that allow cello (and/or other stringed instruments) use in the rain or snow. Without wishing to be bound by any one theory of this embodiment, it is believed that bowing a stringed instrument in the rain leads to sticky bow syndrome, via hydrophilic (and capillary) adhesion of water to bow hairs and rosin. This adhesion makes a mess out of bowing and otherwise may prevent cellists from joining their brethren woodwinds and brass players of the marching band during less than perfect weather. To counteract this tendency, a hydrophobic rosin is provided that gives friction to the bow but that repels water.
A variety of hydrophobic materials can stick to natural horsehair and/or synthetic bow hair and can be appreciated or selected by a skilled artisan upon routine optimization. The art of hair and leather treatment is replete with numerous examples of lotions, pastes, waxes, cakes, dispersions and the like that impart water repellency to hair or leather and are candidates as rosins on bow hair to improve bowing friction with strings. Desirably, a water repellent rosin is prepared by neutralizing the abietic acid rosin compositions via, for example, adding a cation such as aluminum and making a salt by reacting with base. The use of a more hydrophobic rosin made by base treating abietic acid containing material for marching cellos outside is particularly contemplated. Chemical reactions relevant to this are known, and some may be found in the corresponding sections of one or more of U.S. Pat. Nos. 5,037,956; 5,773,391; 5,886,128; 6,013,727 and 6,469,125 the relevant sections (particularly chemical agents and reactions) of which are specifically incorporated by reference in their entireties. The paper making industry often uses rosin systems that are made hydrophobic and such prior art chemistry particularly is contemplated. In an embodiment, a synthetic bow hair with more hydrophobicity (water repellency) than regular horse hair is combined with a hydrophobic rosin and used for bowing the outdoor stringed instrument. Desirably, composite bows are used that are made from synthetic materials to alleviate warping.
Gothic rosin. In an embodiment, dark blood-red rosin is constructed by adding ferric ions to melted rosin, or rosin component(s) such as abietic acid during manufacture. More preferably, iron porphyrin is added. Biologically sourced iron porphyrin is preferred because this material is darker than oxygenated porphyrin-heme globin protein of blood, is more stable (being only the heme (ferroporphyrin) and not the protein part of hemoglobin) and is less allergenic compared to the use of dried animal blood. Preferably, ferroprophyrin in dry form is added directly to hot rosin or to raw materials during rosin manufacture. Other porphyrins can be used, but iron porphyrin is preferred. The porphyrin can be added to about 0.1%, 0.3%, 1% or as suited for visual effect. An advantage of gothic rosin is that the rosin powder is less noticeable on the instrument during and after bowing with a rosined bow.
Although the above description focuses on desired embodiments, the same materials and methods are intended for use in other systems as well. For example, although described in the context of a cello, many of the embodiments are intended for use with electric violin systems too. Other permutations of embodiments will be appreciated by a reading of the specification and are within the scope of the attached claims.
In this example music was played on a cello having a bridge weighing less than 3 grams, with individual neoprene foam pads between the bridge feet and a hardwood base, the neoprene having a thickness of between ⅛ and ¼ inch and a durometer of between 10 and 30. Good results were obtained. Replacement of the neoprene with harder neoprene of durometer rating of 40, 60 and 80 yielded sound that was progressively more dull. Replacement with rubber of the same approximate durometer yielded a more durable system. For the bridge material, maple gave the best results. Oak yielded a slightly more dull sound. Soft woods were studied and gave some interesting sounds, with unexpected resonances away from the natural open string frequencies.
Bridges were made by cutting down standard German made maple cello bridges. More than ⅘ of the bridge wood was removed. A similar bridge made from bola wood, which was heavier and gave poor (dull) sound performance. Thin plastic piezo sensors were positioned under the neoprene (and rubber, when used) pads and above the hardwood base. When individual piezo sensors under the left and right bridge feet were compared, it was found that sound from bowing a given string was more brilliant from the sensor located under the bridge foot closest to the string.
Other embodiments and combinations of embodiments will be appreciated by a skilled artisan upon reading the specification and are intended to be within the scope of the claims. All cited documents and particularly structural details of instruments, circuits and devices used for electric stringed instruments described in cited patents and patent applications are specifically incorporated by reference in their entireties.
This application is a continuation in part of U.S. Ser. No. 11/384,449 filed Mar. 21, 2006 (now U.S. Pat. No. 7,385,125), which receives priority from U.S. Ser. No. 60/664,368 filed Mar. 23, 2005 and to U.S. Ser. No. 60/704,915 filed Aug. 3, 2005, both of which are entitled “Electric Cello and Cello Systems” and name Marvin Motsenbocker as inventor. This application also receives priority from U.S. Ser. No. 61/044,480 filed Apr. 12, 2008 and entitled “Acoustic Speaker System with Bass Capability.”
| Number | Date | Country | |
|---|---|---|---|
| 60704915 | Aug 2005 | US | |
| 60664368 | Mar 2005 | US | |
| 61044480 | Apr 2008 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11384449 | Mar 2006 | US |
| Child | 12136012 | US |
