Apparatus and method for momentarily decreasing audio volume

APPARATUS AND METHOD FOR MOMENTARILY DECREASING AUDIO VOLUME

0002Technical Field This invention relates to audio volume control and more particularly to an apparatus for randomly and momentarily sharply decreasing audio amplitude of musical entertainment such as by electric guitar. Background Art An instrumentalist may set the volume and the tone of the audio at a desired setting prior to strumming a guitar. However, the volume or tone control cannot be adjusted by the instrumentalist without interrupting his playing. This invention provides a device which is interposed in the audio circuit and permits the instrumentalist to momentarily interrupt or decrease the audio volume by substantially normal hand movement while picking guitar strings resulting in a closely spaced momentarily lull or decrease of audio and a resulting quick return to the preset volume. This action generates a pulse-like audio which is sometimes desirable and is not possible with presently used equipment. Disclosure Of The Invention In one embodiment, a phototransistor is housed in a portable case having a light admitting window. The case is removably attached to the sound board of an electric guitar adjacent the strings. Jack and plug equipped leads connected with the phototransistor are interposed in the audio circuit between the guitar and an audio amplifier. In a second embodiment, the phototransistor is mounted beneath a window in the sound board of the guitar and leads from the phototransistor are interposed in the audio circuit between the guitar and an audio amplifier. Brief Description Of The Drawings Figure 1 is a diagram illustrating a fragment of an electric guitar having the device interposed in series in the audio circuit from the guitar to an amplifier in series with a speaker; Figure 2 is a fragmentary top view, to an enlarged scale, of the device installed in a protective case having the window equipped case top removed; Figure 3 is a diagram similar to Figure 1 illustrating the device installed beneath a light admitting window of a guitar sound board; and, Figure 4 is a diagram illustrating the device interposed in an audio circuit between the audio source and an amplifier connected in series with a speaker. Best Mode For Carrying Out The Invention The reference numeral 10 indicates a fragment of a substan- tially conventional electric guitar having a neck 12 supporting strings 14 extending across a pickup bar 16, mounted on the sound board 18. An audio volume control 20, and tone control 22 are conventionally mounted on the guitar sound board 18 and the guitar audio is accessed by a plug 24 open through a wall of the guitar which normally receives a telephone jack on one end of a lead 28 connected at its other end with a speaker 30 in series through an amplifier 32. The above description is included to show the combination with which the device 35 may be used. The device 35 includes an elongated, generally rectangular in cross section, case 36 having a hollow interior and provided with an inner wall 38 forming a compartment which houses an N- P-N phototransistor 40 below a transparent window 42 in the case cover. The phototransistor case 36 is characterized by a flat bottom surface, not shown, which is secured at a selected location to the guitar sound board 18 as by VELCRO, not shown. A pair of leads 44 and 46, respectively, having a jack 48 and plug 50 at a respective end thereof have their opposite end portions contained by the case 36. The ground wires 52 of the leads 44 and 46 are connected together and the audio wires 54 and 56 of the respective leads 44 and 46 are respectively connected to the negative terminals of the phototransistor 40. In the operation of the embodiment illustrated by Figs. 1 and 2 and assuming the device 35 has been interposed in the audio circuit as disclosed hereinabove, the instrumentalist presets the controls 20 and 22 to a desired level and while picking the strings of the guitar 10 moves his hand, not shown, over the window 42 which interrupts or at least minimizes the ambient light reaching the emitter of the phototransistor and sharply increases the impedance from the collector to the ad itter resulting in a sharp reduction in the volume of the audio which, with the return of ambient light to the phototransistor, results in an abrupt return to full volume of the audio. This action is repeated as desired by the instrumentalist while playing the guitar. Referring also to Figs. 3 and 4, the reference numeral 10' indicates a similar electric guitar forming an audio source having the controls 20 and 22 mounted on its sound board 18 and provided with an outlet plug 24 similarly connected by a wire 28 with a speaker 30 through an amplifier 32. In this embodiment a transparent window 60 is formed at a selected location in the sound board 18 and the light sensor is mounted in the guitar below the window 60 with is leads 44 and 46 interposed in the audio circuit to the plug 24. As best shown by Fig. 4 a bypass switch 62 is connected between the audio wires 54 and 56 of the leads 44 and 46 for isolating the light sensor from the audio circuit, the bypass switch armature control being shown by the small circle 62 on the sound board 18. The operation of the instrument contained device is substantially identical with that described hereinabove for Figs. 1 and 2 in which the instrumentalist playing the guitar 10' moves his hand over the window 60 to achieve identical results as described hereinabove. When the light sensor is mounted on another audio source such as a tape player, radio, or CD-player, not shown, pulsing action of the audio is achieved by moving an opaque object, such as a business card 61, across the light sensor. When desired the bypass switch 62 may be closed to isolate the light sensor from the audio circuit.