WO1992004711A1

WO1992004711A1 - Method and device for improving sound in guitars and similar stringed instruments

Info

Publication number: WO1992004711A1
Application number: PCT/US1990/005056
Authority: WO
Inventors: Shin Hsing Chen
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-09-06
Filing date: 1990-09-06
Publication date: 1992-03-19
Anticipated expiration: 1993-03-06

Abstract

A wishbone shape articulated lateral drive means (19, 20) is mounted on the inner panel of the back plate (13) in a stringed instrument to energize and drive said plate (13) sideways causing sound box (15) panels to generate phase distinct vibrations as a result of sound boards' (12, 13) unison flapping movement so that clarity and response of tones are improved. In order to combine the improved sound with the original sound of the instrument for increasing the tonal range, manual switching capability (21) is provided within the sound box (15) for selection of tone colors from outside the instrument. Treble enhancing means (45, 47) additionally provided to brighten the instruments' sound in general and highlight the treble in particular so that tone color is improved beyond that which can be provided by conventional instruments.

Description

METHOD AND DEVICE POP IMPROVING SOUND IN GUITARS AND

SIMILAR STRINGED INSTRUMENTS

This invention relates to improvement of sound in stringed instruments such as guitars and similar instruments which have hollow bodied resonating means and is more particularly

concerned with tone color, response, and range effected by said means or the sound box. Generally, the sound box comprises a sidewall structure and a set of at least mildly arched sound boards that vibrate and stir the surrounding air to create and propel sound waves through a hole or "F " holes in top board of the instrument.

These conventional instruments such as guitars have well established designs and the sound box is rather vacuous in construction with bracings inside forcing and forming a mildly arched bade plate and a somewhat less arched tor board. The later also serves as an anchor base for the string bridge that receives and propagates vibratory movements from the energized (plucked or bowed) strings starting from the bridge base at the center of said board toward the sidewall structure, and continuously to the back plate, in ripple manner and involving time lapes in the process. One design (U3-A-360, 317) incorporates multiple push rods connected to the sidewall structure forming a non distancevariable construction. Another design (US-A 4,343,940) includes a sound transmitting assembly that utilizes one-piece straddle bridge with conductor means to energize the central area of the back plate in a permanently engaged mode.

These designs all fail to provide a distinctly superior tone production means for the instruments to fully satisfy modern day virtuosi's demand because: 1, the nipple manner of vibratory propagation, due to said time lapes, allows the phases to overlap or one rhase to disturb the other resulting in muddy sounds. 2, said time lapes also contributes to "dragging" of notes played and hinders musicians from performing more rapid riffs or achieving clear contrapuntal lines. 3, the multiple rod design forming a non distance-variable, therefore rigid, sidewall structure merely constrains the sound boards and affects the production of desirable sounds. 4, the one-piece straddle bridge design has merit in causing the central area of the back plate to vibrate in synchronous phase with the same area of the top but, due to the non-articulated or nonlateral driving nature of the bridge member, it leaves the remaining large area of the sound box panels to lag behind phasewise, preventing a full potential in clarity of sound production from being realized.

5, said permanently engaged assembly, lacking in tone selection control, provides only a limited tonal range to no wider than that of the traditional design and its lack of treble enhancing means further prevents production of brilliant sounds.

The invention as claimed is to remedy these shortcomings. It solves the problems in designing acoustic stringed instruments with improved clarity in tone that can only be achieved by generating synchronously phased vibratory movements over the sound box panels with practically no time lapes in said movements. The improvement allows productions of quick responding, non- dragging and non-overlapping notes (when so desired) from the instruments and it is achieved by providing within the sound box an articulated straddle bridge which mainly functions as a laterally directed drive means that energizes and drives the peripheral areas of the back plate sideways, that is, it stretches the plate toward both sides during the energizing phase of a vibratory cycle. The energized drive simultaneously causes the entire sound box to flatten or the mildly arched both sound boards to flap in unison, bypassing the ripple factor, thereby phase distinct vibratory movement of the sound box realized.

The invention also extends the tonal range to beyond the limit of that of conventional acoustic stringed instruments through enhancing treble tone in general and by incorporating tone selector means that allows musicians to instantly disengage, engage, or manipulate the tensions of the new acoustic driver assembly for selecting dark, medium, or brighter tone colors respectively by a flip of the manual switch means from outside of the instrument.

It is highly desirable for a rolyphcnic instrument such as a guitar to have capabilities such as disclosed above, to sound clearly and respond quickly notewise when the instrument is played, especially where the music involves complex, dissonance inclined contrapuntal compositions. By combining an extended tone color range and the improved tone quality in the instrument, there is provided an advantageous method and device for perfect adaptation in stringed instruments to meet musicians' demand acoustically. Another benefit of the invention pertains to easy retrofit of the device to improve existing countless guitars and similar instruments acoustically by providing easy installation kits for owners of said instruments.

One way of carrying out the invention is described in detail below with reference to drawings which illustrate only one specific embodiment, in which:-

Figure 1 is a schematic elevational detail view looking upwardly through the body of the guitar of Figure 2 showing therein the new sound improvement-selection mechanism of the present invention.

Figure 2 is a perspective view of the body of the guitar representing a stringed instrument providing reference for

Figure 3.

Figure 3 is a fragmental sectional elevational view of the sound improvement-selection mechanism.

Figure 4 is a fragmental vertical detail view taken along the sectional line IV-IV in Figure 3.

Figure 5 is an enlarged detail view of the tone selection assembly showing disengaged mode (a), engaged mode (b), and tensioned mod (c).

The figures show a guitar, or similarly constructed

stringed instruments comprising a body or sound box 15 including top board

back plate 13, a sidewall structure 14 joini ng said boards and defining a chamber 15 into which a sound hole 17 through the sound board 12 opens under playing strings 15

stretched lengthwise.

According to the presant invention, the assembled device 10 and 21 comprires an energy diverting lateral drive mechanism 19 and 20 within the sound box chamber 15 and is switchably connected to the treble stringo 18" area of anchoring member 59 via a tone selection switch assembly 21, including a treble tone enhancing pin screw 47 . The back plate 13 provides anchor bearings for drive mechanism 19 and 20 by means of drive tips 23 and drive notches 24 combination anchored by quick mount spring fasteners 27.

In a prefered construction, the drive arms 19 and 20 are cooperatively disposed in a upwardly convergent relation, with lower end respective rocker tips 23 received in complementary notches 24 in an existing bracing bar 25, or in equivalently patched wood segments where such bracing is absent or dislocated, rockably fastened by spring fasteners 27. The bracing 25 is generally glued onto the inner back panel in parallel with and beneath the off-upper edge of member 5r above. At their upper ends, the arms 19 and 20 are connected in an articulated manner, wherein the arm 19 has a downward facing inverted V notched bearing 29 which receives complementary tip 28 of drive arm 20, together forming an expanded wishbone configuration. Resillient spring clamps 30 and 27 fasten respective rocker couplings for buzz free movement. Said articulated coupling of the upper arm parts 23 and 29 forms a lateral distance expandable driving between bearing notches 24's.

Mounted rigidly on the crown of the arm 19 for effecting said driving is an upwardly projecting needle pointed fulcrum spindle 32 which engages in a complementary fulcrum socket 33 in the lower side face of the lever 31 and fastened by a spring clamr 62 that loops through the eye 61, arround the fulorum coupling, and holds the lever 31 firmly but rockably in place. One end of the lever 31 has a bifurcation 34 in which is

received the upper thrust relation by the bifurcation 34 and maintained by biasing means comprising a string member 33 engaged at one end with the lever 31 and at its opposite end with the post 35. The post 35 is rigidly supported by means of the bar 25 into which a lower threaded terminal 39 of the post is secured and rigidly locked by mears of a lock nut 40. From the bar 25, the post 35 extents upwardly through a clearance hole 41 in the arm 19. It its energy receiving end 31' of the lever 31 there is transversely welded coupling rod 3A for the paired spiral cam fingers 52 of the switching mechanism 21. Said rod 53 is positioned so that each segment is within the orbit of the tip of the parallel pair cam fingers 52. These fingers have graduated radii for varying the distance and the tension of the grip of the rod 53 to engage assembly 21 with assembly 10 when said fingers 52 are turned and said radii reduced. Further turning of said fingers 52 causes said energy lever tip 31' to be pulled to slide lower in the direction of journal bearing 51 and exerts varying degree of tensions to said boards 12 and 13 via post member 35, and post stem 42 of switching assembly 21.

Said assembly 21 includes a vibratory force exerting cradle bar 45 which is fixedly secured to the underside of the board 12 and generally in line with the treble strings 18' as by means of a metal treble tone enhancing pin screw 47 with its pin head in contact with the treble section of saddle 66. Said pin screw 47 functions to directly channel vibratory energy tc the board 12, or both boards 12 and 13 and prevents treble energy from being absolved by the wooden material of member 59.

Center biased spring retainers 45 retain an inverted L sliding beam 43-post stem 42 vibratory force exerting extension for said cradle bar 45 with its half round beam segment 43 coupled firmly within the channel 44 of cradle bar 45 forming the core of said tone selection means 21 by affording said stem 42 to move and engage with lever tip 31' to effect driving of assembly 10. Said post stem 42 is in immediate proximity to the lever contact edge 31' mounted on the free standing driver, assembly 10 and, at its stem terminal 42', a transverse bearing 51 is provided to carry a switching journal 50 which, in turn, carries said cam fingers 52 in an engageable relationship with said couplirg rod 53. A light weight switch body extension 49 is provided, allowing an ever-accessible helix grip sections 58 exposed to the sound hole opening, and the extension end 55 is securedly born by upper bracing 57. For "F" holed instruments, a switch rod such as 49 may be alternatively designed to pass through the end pin of an instrument for similar tone selection rurpose. Hardwood, light weight metal, or a combination of both may be used for the parts of said device.

Claims

Claims :

1. Method and device for improving sound in terms of tone response, tone color, and tone range in guitars and similarly constructed stringed instruments having a sound box (15) with a set of at least mildly arched sound boards (12, 15) and assembled within said box (15) comprising: vibratory drive means (19,20) for effecting lateral drive of said box (15) to produce quick responding clear sounds; treble tone enhancing means (45, 47) to brighten sounds; and tone selection-control means (21) for extending the range of the sound of said

instruments, characterised in that said box (15) panels move in synchronous vibratory phases when energized by the string vibratory force, thereby improving clarity in tone and response in notes played, and said switching means (21) allows musicians instantanous choices of original dark, medium with clarity, bright with clarity in tone colors by selecting disengaged mode (Figure 5a), engaged mode (Figure 5b), or tensioned mode (Figure 5c) respectively in the switching assembly (21) by manipulating control means (58) from outside of the instrument.

2. Method and device for improving tone in guitars and similarly constructed instrument having sound boards (12, 13) and sidewall structure (14) forming a sound box (15) comprising treble enhancing means (45, 47) characterised in that said means includes pin screw (47) having one end in contact with the treble strings (18) section of the string saddle (66) and the other end mechanically engages bar member (45) thereby treble vibratory energy is channeled to said board (12) or both boards (12, 13) without said energy being absolved by the wooden bridge member

(59).

3. Method and device for improving sound in guitars and similar stringed instruments having a sound box (15) with a set of at least mildly arched sound boards (12, 13) and retrofit sound improvement device kit (10, 21) adapted to be mounted on inside panels of said boards (12, 13) and within said box (15), characterised in that said device kit (10, 21) provides quick mount fasteners (47, 30, 27 , 62, 48) so that said kit device (10, 21) can be assembled from outside of the instrument with minimum tooling requirement.

4. A device as claimed in any preceding claim

characterised in that said drive means includes drive tips (23, 28) and bearing notches (24, 29) couplings.

5. A device as claimed in any preceding claim

characterised in that said device (10, 21) includes spring clamps (30, 27, 37, 38, 48, 62) for buzz free operation.

6. A device as claimed in any preceding claim

characterised in that said control switch means (21) includes cradle bar (45) rocker beam (43) coupling for engage-disengage function.

7. A device as claimed in any preceding claim

characterised in that said switch means (21) includes radii variable spiral fingers (52).

8. A device as claimed in any preceding claim

characterised in that said control switch means (21) includes switch body extension (49) and helix grip (58) carried by said extension (49) enabling ever access of said grip (56) from outside of the instrument.

9. Method and device as claimed in any preceding claim characterised in that said drive means (19, 20) comprises segments joined wishbone shape articulated distance variable energy diverting configuration so that said boards (12, 13) are effected to stretch sideways and said boards (12, 13) are thereby caused to flap in unison to achieve phase distinct vibratory movement of said box (15) panels so that both clarity in tone and response in notes improved.