GB2068623A

GB2068623A - Pick-up for an electrical musical instrument of the stringed type

Info

Publication number: GB2068623A
Application number: GB8030631A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-01-28
Filing date: 1980-09-23
Publication date: 1981-08-12
Also published as: CA1180583A; IT1133880B; AU544537B2; GB2068623B; SE8006665L; AU6306980A; FR2474734B1; FR2474734A1; IT8025319A0; DE3038994A1; NL8005629A; JPS56111891A

Abstract

Pick-up for stringed intrument includes two series connected coils (36,46) with a capacitor (38) connected in parallel with one of the coils (36) to shunt that coil to ground for other than bass frequencies whereby the bass frequency characteristic is enhanced. In one embodiment the shunted coil (36) is wound in one direction around a permanent magnet (30) with its north poles adjacent the strings and is located at a point one-third of the distance between the end of the neck connected to the body and the bridge so as to be positioned to receive bass frequencies better. The other coil (46) is wound in the opposite direction around an oppositely directed magnet (40) and is located at a point halfway between the first coil and the bridge. Thus a humbucking arrangement is provided. In a modification each coil is wound in opposite directions around a pair of oppositely directed magnets to provide enhanced humbucking. <IMAGE>

Description

SPECIFICATION Pick-up for an electrical musical instrument of the stringed type Technical field The present invention relates to a pick-up for an electrical musical instrument of the stringed type and, more particularly, to a pick-up for an electrical musical instrument of the stringed type which will enhance the bass frequency characteristics of such instrument.

Background of the prior art The present invention relates broadly to electrical musical instruments of the stringed type. It is particularly applicable to an electrical bass guitar or similar musical instrument having a plurality of stretched strings extending across a body and a neck, between the head of the instrument and a bridge assembly connected to the body, in which the strings are caused to vibrate by plucking or picking same.

in order to derive an output from such an electrical bass guitar or other similar electrical musical instrument, the instrument is conventionally provided with an electromagnetic pick-up comprising a number of magnetic elements (pole pieces) having wound therearound a conductive coil. Typically, one such magnetic element is disposed directly beneath each string of the instrument. The strings are constructed of a magnetizable substance, such as steel, and, therefore, become part of the conductive path for the magnetic lines of flux of the pole pieces.

Accordingly, when any of the strings are caused to vibrate, this causes a disturbance in the magnetic field of the associated pole piece. This has the effect of generating a voltage in the conductive coil, which voltage may be suitably amplified and.transmitted to a loudspeaker system.

With such an electromagnetic pick-up construction, a number of problems exist. Electric guitars and other similar electrical musical instruments are used in areas having strong magnetic fields from lighting fixtures, motors, transformers, and the like, and these magnetic fields are sensed by the pick-up as an extraneous noise source. In the United States, such source typically has a frequency of 60 Hz, the usual power line frequency. These magnetic fields induce voltage in the coil which are also amplified and transmitted to the loudspeaker system, manifesting themselves in an objectionable hum.

In order to overcome this problem, it is known to provide a pick-up for an electrical musical intrument including a pair of identical pick-up assemblies, each having a plurality of magnetic pole pieces and a coil, the pick-up assemblies being positionable in parallel, spaced, closely adjacent relationship. All of the pole pieces of one of the pick-up assemblies have their north poles adjacent to the strings and their south poles relatively remote from the strings whereas all of the pole pieces of the other pick-up assembly having their south poles adjacent to the strings and their north poles relatively remote from the strings. The coils of the two pick-up assemblies are wound in opposite directions and the two coils are connected either in series or in parallel.Because the direction of current flow in each coil is governed by the magnetic polarity, the direction of current flow in one coil is opposite to that of the other coil for each string. However, since the directions of the windings of the two coils are opposite, the signal induced in each coil as a result of string vibrations is additive and the output signal is the sum of the signals induced in each coil.

On the other hand, signals picked up by the coils from power line sources produce currents in the coils which are independent of the magnetic polarity and, accordingly, such power line sources produce voltages that are in phase. However, since the coils are wound in opposite directions, these in phase signals cancel and the output signal is the difference between the power line signals induced in each coil.

This means that any noise from power line sources, which is otherwise manifested as an objectionable hum, is effectively reduced or cancelled. It is for this reason that such an arrangement is typically characterized as a humbucking arrangement.

Another industry recognized problem, not neces sarilywith a pick-up peruse, is the fact that the human ear is not as sensitive (efficient) to bass frequencies as it is to midrange and high frequencies. A similar comment may be made with regard to loudspeakers and other music production systems. On the other hand, modern music, especially disco music and rock music, heavily emphasizes the use of bass frequencies. Therefore the music industry has continuously attempted to boost the bass frequency output of stringed instruments, especially in the case of bass guitars. In the past, this has been done by giving attention to the speakers, baffles, tone control circuits for electro-magnetic pick-ups, and the like.

However, heretofore, none of these techniques have provided the desired level of bass frequency enhancement.

Brief summary of the invention According to the present invention, there is provided a pick-up for an electrical musical instrument of the stringed type which substantially enhances the bass frequency characteristics of the instrument to compensate for the insensitivity of the human ear of these frequencies. This is achieved by positioning a pair of pick-up assemblies at optimal locations on the body of the instrument and significantly increasing the bass frequency output of that one of the pick-up assemblies which is positioned relative to the strings so as to be most sensitive to the base frequencies. The predominantly bass frequency output of this particular pick-up assembly is added to the predominantly midrange and high frequency output of the other pick-up assembly to provide the desired range of frequencies.

Briefly, the present invention relates to a pick-up for an electrical musical instrument of the type including a body, a neck having a head, a bridge assembly connected to the body, and a plurality of strings extending between the head and the bridge assembly and includes: a first pick-up assembly positioned approximately one-third of the way be tween the end of the neck connected to the body and the bridge assembly and comprising a first plurality of pole pieces operatively associated with the strings of the instrument, a first coil wound around the first plurality of pole pieces, and a capacitor connected across the first coil for providing a shunt across the first coil for all frequencies other than useful bass frequencies; and a second pick-up assembly positioned in parallel, spaced relationship to the first pick-up assembly, approximately halfway between the first pick-up assembly and the bridge assembly, and comprising a second plurality of pole pieces and a second coil wound around the second plurality of pole pieces, the first and second coils being connected in series between ground potential and the output of the pick-up.

It is therefore an object of the present invention to provide a pick-up for an electrical musical instrument of the stringed type which has a substantially increased bass frequency content. It is a feature of the present invention to satisfy this object by providing a pick-up for an electrical musical instrument having a pair of pick-up assemblies optimally located relative to the head and bridge of the instrument and means for shunting all frequencies other than useful bass frequencies from the pick-up assembly located to have maximum sensitivity to bass frequencies. An advantage to be derived is that the bass frequency output of such pick-up is substantially enhanced. A further advantage is that the present pick-up may be used with conventional speakers, baffles, tone control circuits and the like without the facility for bass boost.A still further advantage is that these objectives are achieved in a simple and efficient manner.

Brief description ofthe drawings Still other objects, features, and attendant advantages of the present invention will become apparent to those skilled in the art from a reading of the following detailed description of the preferred embodiments constructed in accordance therewith, taken in conjunction with the accompanying drawings wherein like numerals designate like parts in theseveral figures and wherein: In the drawings Figure lisa top plan view of an electrical bass guitar incorporating the present invention; Figure 2 is a schematic representation of the pick-up assemblies of the pick-up of the bass guitar of Figure 1 and showing a first embodiment of the present invention; and Figure 3 is a view similar to Figure 2 showing a second embodiment of the present invention.

Detailed description of the invention Referring now to the drawings and, more particu larly, to Figure 1 thereof, the present invention is illustrated as being incorporated in an electrical bass guitar, generally designated 10, including a body 11, a fretted neck 12, and a head 13 being connected to one end of neck 12, the other end of neck 12 being connected to body 11. Tensioned between head 13 of bass guitar 10 and a bridge assembly 14 connected to body 11 are a plurality of strings 15-18 which lie in a single plane parallel to the face of body 11.

Strings 15-18 are constructed of a magnetizable substance, such as steel, and are graduated in diameter in a conventional manner. In order to derive an output from guitar 10, it is provided with an electromagnetic pick-up, generally designated 20, which forms the subject matter of the present invention. Vibrations of strings 15-18, as a result of plucking or picking the same, produce an electrical signal in pick-up 20, which signal may be suitably amplified and transmitted to a loudspeaker system(.

Pick-up 20 has a general configuration which is known in the prior art. Specifically, in order to provide humbucking, pick-up 20 includes at least first and second pick-up assemblies 30 and 40, pick-up assembly 30 comprising a plurality of identical magnetic elements (pole pieces) 31-34 which may be magnetized in any one of several ways known to those skilled in the art and pick-up assembly 40 includes a similar plurality of identical magnetic elements (pole pieces) 41-44. The number of pole pieces 31-34 and the number of pole pieces 41-44 are preferably identical and preferably the same as the number of strings 15-18. In any event, pole pieces 31-34 and 41-44 are mounted in body 11 in a conventional manner and held in position by suitable caps 35 and 45, respectively.

With reference also to Figure 2, it is noted that in this embodiment, all of pole pieces 31-34 of pick-up assembly 30 have their north poles adjacent to strings 15-18 and their south poles relatively remote from strings 15-18, whereas all of pole pieces 41-44 of pick-up assembly 40 have their south poles adjacent to strings 15-18 and their north poles relatively remote from strings 15-18. This arrangement may be reversed.

A coil 36 formed from a large number of turns of fine conductive wire is wound around pole pieces 31-34 of pick-up assembly 30 whereas a coil 46 formed from a large number of turns of fine conductive wire is wound around pole pieces 41-44 of pick-up assembly 40. The wire in coils 36 and 46 is insulated, such as with varnish or lacquer, and the entire assembly comprising the pole pieces, the supporting plates, and the coils are preferably dipped in a suitable varnish or lacquer. As is known in the art, movement of strings 15-18 as in the strumming or playing of guitar 10, results in voltages being induced in coils 36 and 46. These voltages are transferred to the input circuit of an amplifier and a loudspeaker system.

In order to provide a hum bucking arrangement, coils 36 and 46 are wound in opposite directions.

According to the present invention, coils 36 and 46 are connected in series between ground 21 and an output lead 22. Because the direction of current flow in each coil is governed by the magnetic polarity, the direction of current flow in each coil is opposite to that of the other coil for each string. However, since the direction of winding of the two coils is opposite, the voltages induced in the coils as a result of string vibrations are additive and the signal output on lead 22 is the sum of the voltages induced in each coil.

On the other hand, signals picked up by coils 36 and 46 from the power line service currents in coils 36 and 46 which are independent of the magnetic polarity and, accordingly, such extraneous signals produce voltages that are in phase. However, since coils 36 and 46 are wound in opposite directions, these in phase signals cancel and the signal output on lead 22 is the difference between the extraneous signal voltages induced in each of the coils 36 and 46. This means that any noise from power line sources, typically in the range of 0-150 Hz, which is otherwise manifested as an objectionable hum, is effectively reduced or cancelled. It'is for this reason that the arrangement may be characterized as a humbucking arrangement.

Referring again to Figure 1, it is immediately recognized that the only practical place to locate pick-up 20 is between the end 23 of neck 12 and bridge assembly 14. In theory, it is desirabie to place pick-up 20 halfway between the end points of each string 15-18 since this will coincide with the point of maximum translation of the string at its fundamental frequency of vibration. As pick-up 20 is moved from the center position, it becomes less sensitive to the fundamental frequencies and more sensitive to the harmonics. The problem results from the fact that the location of at least one end point keeps changing as the musician moves strings 15-18 into contact with the fret board on neck 12. Accordingly, certain compromises must be made in choosing the location for pick-up 20.

if pick-up 20 is placed close to bridge assembly 14, it will always be significantly spaced from the string midpoints and will have little sensitivity to the fundamental frequencies. On the other hand, if pick-up 20 is placed very close to end 23 of neck 12 so as to be close to the string midpoints when the strings are not brought into contact with neck 12, pick-up 20 will have little sensitivity-to the fundamental frequencies when the musician engages strings 15-18 close to end 23 otneck 12. Furthermore, for reasons discussed:previously, it is desired that maximum sensitivity exist to the fundamental tones to increase the bass sensitivity of pick-up 20.

With reference to Figures 1 and 2, the objects of the present invention are achieved by positioning pick-up assemblies 30 and 40 in parallel, spaced relationship on body 1 1.As shown in Figure 1, pick-up assembly 30 is positio ed approximately one-third of the way between end 23 of neck 12 and bridge assembly 14. Thisvplaé pick-up assembly 30 at a location where it will be cioséto the midpoints of strings 15-18 when the mue6i'an: ís playing instru- ment 10, since statistically, most fretting is done between the instrument nut 19 andthe twelfth fret.

Pick-up assembly 40, on the other hand, is positioned one-third of the way between bridge assembly 14 and end 23 of neck 12 (halfway between bridge assembly 14 and pick-up assembly 30), where it has greater sensitivity to the harmonics. Pick-up assembly 40 is, therefore, primarily responsible for reproducing the midrange and high frequencies.

Still further, and in accordance with the teachings of the present invention, a capacitor 38 is connected in parallel with coil 36, as shown in Figure 2.

Capacitor 38 has a value so that it will effectively shunt to ground 21 all frequencies other than the useful bass frequencies which it is the desire of the present invention to enhance. In the case of a bass guitar, where open E has a frequency of 41.2 Hz, the value of capacitor 38 is selected so that its effect begins to become significant at cut-off of frequencies, but would want capacitor 38 to function as an open circuit at frequencies in the 40-60 Hz range and to operate as a virtual short circuit at frequencies above 150 Hz. The cross-over point would be in the vicinity of 100 Hz. in the case of a conventional guitar, where open E has a frequency of 82.41 Hz, the value of capacitor 38 would be selected to have a significant effect at a frequency in the 150-200 Hz range.

In other words, it is the teaching of the present invention to locate pick-up assembly 30 at a location where it will have maximum sensitivity to the fundamental frequencies of strings 15-18 and to use a capacitor 38 in parallel with coil 36 to shunt frequencies other than useful bass frequencies.

Then, the output of pick-up assembly 30 is combined with the output of pick-up assembly 40, the latter being sensitive primarily to the midrange and high frequencies. The outputs of these two coils are combined by connecting same in series between output lead 22 and ground 21. When this output is applied to a conventional amplification and louds peakersystem, pick-up 20 will provide bass guitar 10 with a substantially enhanced low frequency output.

According to the embodiment of the invention shown in Figures 1 and 2, pick-up assembly 30 consists of a single set of pole pieces 31-34 and a single coil 36, as does pick-up assembly 40. However, other configurations will be evident to those skilled in the art. For example, and with reference to Figure 3, a pick-up 50 for bass guitar 10 may include a pick-up assembly 60 which is a dual pick-up and a pick-up assembly 80 which is also a dual pick-up. In other words, pick-up assembly 60 may include two sets of pole pieces 61-64 and 65-68, each having its own coil 69 and 70, respectively, pole pieces 65-68 having an opposite magnetic orientation from pole pieces 61-64 and coils 69 and 70 being wound in opposite directions. By connecting coils 69 and 70 in series or in parallel, as discussed previously, a humbucking arrangement is provided. In either event, a capacitor 71 would be connected in parallel with coils 69 and 70 for the reasons described previously with regard to pick-up 20.

In like manner, pick-up assembly 80 will include two sets of pole pieces 81-84 and 85-88, each having its own coil 89 and 90, respectively, pole pieces 81-84 and pole pieces 85-88 having opposite magnetic orientations and coils 89 and 90 being wound in opposite directions. Coils 89 and 90 are connected in series or in parallel, but the combination is connected in series with coils 69 and 70. In the case of pick-up 50, switch means may be provided for shorting either coil 69 or coil 70 and switch means may also be provided for simultaneously shorting either coil 89 or 90. The reasons for the desirability of removing one of the two coils in a dual pick-up assembly from the circuit are known to those skilled in the art. Those skilled in the art will also recognize that pick-up 50 is a more effective hum bucking arrangement than pick-up 20.

It can therefore be seen that according to the present invention, there is provided a pick-up for an electrical musical instrument of the stringed type which substantially enhances the bass frequency characteristics of the instrument to compensate for the insensitivity of the human ear to these frequencies. This is achieved by positioning a pair of pick-up assemblies at optimal locations on the body of the instrument and significantly increasing the bass frequency output of that one of the pick-up assemblies which is positioned relative to the strings so as to be most sensitive to the bass frequencies. The predominantly bass frequency output of this particular pick-up assembly is added to the predominantly high frequency output of the other pick-up assembly to provide the desired range of frequencies.

While the invention has been described with respect to the preferred physical embodiments constructed in accordance therewith, it will be apparent to those skilled in the art that various modifications and improvements may be made without departing from the scope and spirit of the invention. Accordingly, it is to be understood that the invention is not to be limited by the specific illustrative embodiments, but only by the scope of the appended

Claims

claims. CLAIMS

1. A pick-up for an electrical musical instrument of the type including a body, a neck having a head, a bridge assembly connected to said body, and a plurality of strings positioned between said head and said bridge assembly, comprising: a first pick-up assembly positioned between said neck and said bridge assembly, said first pick-up comprising: a first plurality of pole pieces operatively associated with the strings of said instrument; a first coil wound around said first plurality of pole pieces; and means connected in parallel with said first coil for providing a shunt across said first coil for frequencies other than useful bass frequencies; and a second pick-up assembly positioned in parallel, spaced relationship to said first pick-up assembly said second pick-up comprising: a second plurality of pole pieces operatively associated with said strings of said instrument; and a second coil wound around said second plurality of pole pieces; said first and second coils being connected in series.

2. The pick-up for an electrical musical instrument as claimed in Claim 1,wherein all of said pole pieces of one of said pick-up assemblies have their north poles adjacent to said strings and their south poles relatively remote from said strings and wherein all of the pole pieces of the other pick-up assembly have their south poles adjacentto said strings and their north poles relatively remote from said strings, and wherein said first and second coils are wound around their respective pole pieces in opposite directions so that the voltages induced therein from vibrations of said strings add and the voltages induced therein from noise sources subtract.

3. The pick-up for an electrical musical instrument as claimed in Claims 1 or 2, wherein said means providing a shunt comprises: a capacitor, the opposite sides of which are connected to the opposite ends of said first coil.

4. The pick-up for an electrical musical instrument as claimed in Claims 1 or 2, wherein said first pick-up assembly is positioned approximately onethird of the distance between the end of said neck connected to said body and said bridge assembly.

5. The pick-up for an electrical musical instrument as claimed in Claim 4, wherein said second pick-up assembly is positioned approximately halfway between said first pick-up assembly and said bridge assembly.

6. The pick-up for an electrical musical instrument as claimed in Claims 1 or 2, wherein said means providing a shunt provides a shunt for frequencies above approximately 150 Hz.

7. A pick-up for an electrical musical instrument comprising: a pair of coils connected in series; and a capacitor connected in parallel with one of said coils for providing a shunt across said one coil for frequencies other than useful bass frequencies.

8. The pick-up as claimed in Claim 7, wherein said coils are connected in series between ground and an output terminal with a common connection point there between and wherein said capacitor is connected between said common connection point and ground.

9. The pick-up as claimed in Claim 7, wherein said coils are connected in series between ground and an output terminal with a common connection point therebetween and wherein said capacitor is connected between said common connection point and said output terminal.

10. The pick-up as claimed in Claims 7,8 or 9, wherein said capacitor provides a shunt for frequencies above approximately 150 Hz.

11. A pick-up for an electrical musical instrument substantially as herein described with reference to and as illustrated in the accompanying drawings.