METAL ATTENUATOR GRILLE FOR MICROPHONE
United States Patent 3830333
A metal attenuator grille for a microphone designed to obviate variations in the attenuation curve owing to environmental changes, comprising a solid metal member having a central opening and a plurality of spaced peripheral openings; the central opening, but not the peripheral openings, may be covered by a grille.
US Patent References:
Sound translating apparatus
Touger et al. - September 1956 - 2761912
Device for the reproduction of sound
Boleslav - June 1958 - 2840178
Sound translating apparatus
Touger et al. - September 1956 - 2761912
Device for the reproduction of sound
Boleslav - June 1958 - 2840178
Application Number:
05/270080
Publication Date:
08/20/1974
Filing Date:
07/10/1972
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Export Citation:
Assignee:
Gould Inc. (Chicago, IL)
Primary Class:
Other Classes:
381/359
International Classes:
H04R1/22; H04R25/00; H04R25/00; H04R1/28
Field of Search:
181/31B,31R,23 179/180,184,188,115,17H,115.5
Primary Examiner:
Tomsky, Stephen J.
Attorney, Agent or Firm:
Ostrolenk, Faber, Gerb & Soffen
Claims:
The embodiments of the invention in which a specific privilege or property is claimed are defined as follows
1. A microphone attenuator comprising a solid plate of nonporous non-absorbent material, having a central opening and a plurality of additional relatively smaller openings radially spaced from the central opening at a distance from the periphery of the center opening greater than the diameter of the central opening, said additional openings each having a diameter substantially smaller than that of the central opening and a grille cloth cover for the central opening, the additional openings being free of said grille cloth.
2. The microphone attenuator grille of claim 9 in which the diameter of each of the additional openings is of the order of one tenth that of the central opening.
3. The microphone attenuator grille of claim 2 in which the additional openings are spaced at a radial distance from the center of the central opening along a circle having a diameter of the order of five times the diameter of the central opening.
4. The microphone attenuator grille of claim 3 in which the additional openings are three in number spaced 120° apart.
1. A microphone attenuator comprising a solid plate of nonporous non-absorbent material, having a central opening and a plurality of additional relatively smaller openings radially spaced from the central opening at a distance from the periphery of the center opening greater than the diameter of the central opening, said additional openings each having a diameter substantially smaller than that of the central opening and a grille cloth cover for the central opening, the additional openings being free of said grille cloth.
2. The microphone attenuator grille of claim 9 in which the diameter of each of the additional openings is of the order of one tenth that of the central opening.
3. The microphone attenuator grille of claim 2 in which the additional openings are spaced at a radial distance from the center of the central opening along a circle having a diameter of the order of five times the diameter of the central opening.
4. The microphone attenuator grille of claim 3 in which the additional openings are three in number spaced 120° apart.
Description:
The present invention relates to a damping disc or grille for a microphone which will attenuate the sound reaching the microphone predictably and without variation.
Previously in order to modify the response curve of a microphone it has been common to use metallic or plastic grills and textile or plastic attenuators. Thus one common practice was to use a plastic foam attenuator adjacent the microphone with a woven attenuator outwardly thereof succeeded by a plastic grille and protected by a wire grille. One of the problems was that the plastic foam or the woven attenuator absorbs moisture in humid atmospheres or as a result of any atmospheric changes and the effectiveness of the attenuator is thus considerably modified.
The principal object of the present invention is to provide a means of modifying the response curve to meet a specific specification with assurance that the response curve will not vary as a result of environmental changes.
A further object of the present invention is the replacement of prior attenuators which were capable of absorbing moisture, such as the plastic or woven attenuator, with a solid wall, preferably metallic, having a central opening and a plurality of additional smaller openings spaced from the central opening to provide the appropriate response curve.
Still a further object of the present invention is the utilization of the arrangement of the smaller openings spaced from the central opening to create a plurality of parallel paths with respect to the main opening; the central opening since it is large enough to permit entry of a foreign object is covered by a grille cloth which may however be subject to some variations owing to humidity changes.
The effect of the parallel smaller openings on the response to the total system is substantially the equivalent to any changes which may occur owing to environmental variations.
The foregoing and other objects of my invention will become apparent in the following description and drawings in which:
FIG. 1 is a side view of a behind the ear hearing air having a microphone protected by a grille in accordance with the present invention.
FIG. 2 is a plan view of the novel microphone grille.
FIG. 3 is a cross-sectional view through the novel microphone grille taken on line 3--3 of FIG. 2.
FIG. 4 is a front view corresponding to that of FIG. 2 showing the application of grille cloth to the interior surface of the microphone grille so that it covers the main central opening but not the peripheral openings.
Referring now to FIG. 1, there is here shown a behdn the ear hearing aid 10 having a microphone 11 therein protected and covered by the grille 12 of the present invention. The grille 12 of FIGS. 2, 3 and 4 is provided with a central opening 13 having a plurality of smaller openings 14, 15 and 16 radially spaced from the central opening. The central opening as seen in FIG. 4 is covered by a grille cloth 18 which is adhesively secured to the central portion of the grille 12 so that it covers the main opening 13 but does not cover the peripheral openings 14, 15 and 16.
The grille 12 is made of a solid material which is not affected by environmental changes. One type of material which may readily be used for this purpose is aluminum.
While the application of the novel grille is shown with respect to hearing aids it of course has many wider applications and particularly to utilization in connection with microphones which are expected to be subject to environmental changes.
In one application where the microphone is much larger than would be used in a behind the ear hearing aid, the relationship of the various openings to each other may be drawn from the following dimensional elements: Where the round grille of FIGS. 2, 3 and 4 has a diameter of the order of 0.898 inches, the central opening 13 will have a diameter of the order of 0.152 inches. The peripheral openings 14, 15 and 16 are then spaced on a circle having the same center as the grille but 0.75 inches in diameter and the three openings 14, 15 and 16 have a diameter of 0.016 inches. It will thus be seen that the peripheral openings are approximately one tenth the diameter of the main opening and the principal opening is of the order of one fifth the diameter of the grille measured to the circle along which the peripheral openings are applied.
By this means therefore the difficulties which arose in connection with prior attenuators which are capable of absorbing moisture are obviated and a simplified microphone attenuator grille is thereby provided.
In the foregoing the invention has been described in accordance with a single illustrative embodiment. Since it is obvious that many variations and modifications may be made within the scope of the disclosure it is preferred that the invention described not be limited by the specific disclosures herein but only by the appended claims.
Previously in order to modify the response curve of a microphone it has been common to use metallic or plastic grills and textile or plastic attenuators. Thus one common practice was to use a plastic foam attenuator adjacent the microphone with a woven attenuator outwardly thereof succeeded by a plastic grille and protected by a wire grille. One of the problems was that the plastic foam or the woven attenuator absorbs moisture in humid atmospheres or as a result of any atmospheric changes and the effectiveness of the attenuator is thus considerably modified.
The principal object of the present invention is to provide a means of modifying the response curve to meet a specific specification with assurance that the response curve will not vary as a result of environmental changes.
A further object of the present invention is the replacement of prior attenuators which were capable of absorbing moisture, such as the plastic or woven attenuator, with a solid wall, preferably metallic, having a central opening and a plurality of additional smaller openings spaced from the central opening to provide the appropriate response curve.
Still a further object of the present invention is the utilization of the arrangement of the smaller openings spaced from the central opening to create a plurality of parallel paths with respect to the main opening; the central opening since it is large enough to permit entry of a foreign object is covered by a grille cloth which may however be subject to some variations owing to humidity changes.
The effect of the parallel smaller openings on the response to the total system is substantially the equivalent to any changes which may occur owing to environmental variations.
The foregoing and other objects of my invention will become apparent in the following description and drawings in which:
FIG. 1 is a side view of a behind the ear hearing air having a microphone protected by a grille in accordance with the present invention.
FIG. 2 is a plan view of the novel microphone grille.
FIG. 3 is a cross-sectional view through the novel microphone grille taken on line 3--3 of FIG. 2.
FIG. 4 is a front view corresponding to that of FIG. 2 showing the application of grille cloth to the interior surface of the microphone grille so that it covers the main central opening but not the peripheral openings.
Referring now to FIG. 1, there is here shown a behdn the ear hearing aid 10 having a microphone 11 therein protected and covered by the grille 12 of the present invention. The grille 12 of FIGS. 2, 3 and 4 is provided with a central opening 13 having a plurality of smaller openings 14, 15 and 16 radially spaced from the central opening. The central opening as seen in FIG. 4 is covered by a grille cloth 18 which is adhesively secured to the central portion of the grille 12 so that it covers the main opening 13 but does not cover the peripheral openings 14, 15 and 16.
The grille 12 is made of a solid material which is not affected by environmental changes. One type of material which may readily be used for this purpose is aluminum.
While the application of the novel grille is shown with respect to hearing aids it of course has many wider applications and particularly to utilization in connection with microphones which are expected to be subject to environmental changes.
In one application where the microphone is much larger than would be used in a behind the ear hearing aid, the relationship of the various openings to each other may be drawn from the following dimensional elements: Where the round grille of FIGS. 2, 3 and 4 has a diameter of the order of 0.898 inches, the central opening 13 will have a diameter of the order of 0.152 inches. The peripheral openings 14, 15 and 16 are then spaced on a circle having the same center as the grille but 0.75 inches in diameter and the three openings 14, 15 and 16 have a diameter of 0.016 inches. It will thus be seen that the peripheral openings are approximately one tenth the diameter of the main opening and the principal opening is of the order of one fifth the diameter of the grille measured to the circle along which the peripheral openings are applied.
By this means therefore the difficulties which arose in connection with prior attenuators which are capable of absorbing moisture are obviated and a simplified microphone attenuator grille is thereby provided.
In the foregoing the invention has been described in accordance with a single illustrative embodiment. Since it is obvious that many variations and modifications may be made within the scope of the disclosure it is preferred that the invention described not be limited by the specific disclosures herein but only by the appended claims.