Patent Application
20190379960
The present invention relates to boundary microphones, and more particularly, a boundary microphone that is mounted in a housing such that the microphone assembly is suspended over a mounting surface with elastic suspension elements such as shock cords to isolate the microphone assembly and decouple the microphone from the housing.
A boundary microphone is a microphone that is positioned near to, or flush with a surface—a “boundary.” Typically, boundary microphones are used for speech or instruments and the mics are placed on or mounted to boundaries such as conference tables. With boundary microphones the microphone capsule is hard-mounted to the housing that contains the capsule. But vibration or other disturbances at the boundary can cause vibration at the mic level; as such, dampening materials are sometimes used between the hard-mounted mic and the housing to minimize negative effects of vibration.
There are known benefits from using boundary mics, including for example, when used to record speech or music because a boundary microphone prevents phase interference between direct and reflected sound, resulting in a natural sound with a flatter frequency response than can be obtained with a stand-mounted microphone at the same distance. By placing the diaphragm of the microphone capsule parallel to and facing the plate boundary provided by the microphone package, the reflected sound delay is reduced, and the resulting comb filter interference frequencies are high enough that they are outside the audible range.
The present invention is defined by a shock-mounting system that isolates the microphone capsule of a boundary mic to completely isolate the mic from other components in the housing. More specifically, the microphone described herein is mounted with elastic shock cords that suspend the microphone in the housing. In an embodiment, one or more microphones may be mounted according to the invention in a housing and each microphone is angularly adjustable so that the microphone points at a desired source of an audio signal, such as a meeting participant or an instrument.
The invention will be better understood and its numerous objects and advantages will be apparent by reference to the following detailed description of the invention when taken in conjunction with the following drawings.
The invention will now be described in detail with reference to the drawings. It will be understood that relative directional terms are used at times to describe components of the invention and relative positions of the parts. As a naming convention, the plane of a boundary (i.e., surface) on which the boundary microphone housing is mounted is considered for this description to be a generally horizontal surface (although in practice the boundary could have any orientation relative to the ground plane). The ceiling is a plane that in most installations is parallel to the floor, though not always. Other relative directional terms correspond to this convention: “upper” refers to the direction above and away from the ground plane; “lower” is generally in the opposite direction, “inward” is the direction from the exterior toward the interior of the adaptor, “vertical” is the direction normal to the horizontal ground plane, and so on.
With reference to all of the figures it will be understood that the boundary microphone assembly 10 comprises housing base 12 that mounts one or plural individual microphone assemblies 100, and that the assembly 10 will include a grille, which is not shown but which attaches to the housing base 12 and which provides a protective and functional enclosure for the one or more microphone assemblies 100—in the drawings the grille is not shown in order to better illustrate the invention (although a grille housing 200 is shown schematically in
With specific reference to
Each microphone assembly 100 is a conventional mic assembly of the type that may be used in a boundary microphone, except the enclosure 102 (which surround the microphone capsule and internal components, none of which are illustrated) of each mic is modified to include at the innermost end 24 (i.e., the ends of the enclosures 102 adjacent hub 12) a pivotal attachment points 26 for connecting the enclosures 102 to a cylindrical suspension ring 12 that surrounds the hub 14 and which defines a mount for the microphone assemblies 100. More particularly, as best shown in
The suspension ring 12 is suspended over board 108 with three elastic shock engagement elements, or shock cords 34 that define loops, and such that the suspension ring is physically separated from the hub 14 and plate 18. In the illustrated embodiment, each cord 34 is in the form of a ring that is looped over a post 36 that is mounted to and extends above board 108, extends around the suspension ring 12, and is looped back over the post 36, as illustrated. Circumferential grooves 38 may be formed in posts 36 to receive the ends of the shock cord, if desired, and similarly, notches may be formed in the interior circumference of the suspension ring 12 to receive the runs of the shock cords where they extend around the suspension ring. The length of the shock cords is such that the cord is under tension when the cord 34 is attached around the post 36, the suspension ring 12, and back around the post, as described, such that the mic assembly 100 is suspended over the board 108 with a space 112 between the lower side of the mic assembly and the board 108. The method of mounting suspension ring 12 just described results in each of the three microphone assemblies 100 being mounted to the suspension ring 12 such that the microphones assemblies are in turn suspended over the board 108 and such that the microphone assemblies are isolated from and not in contact with other components, and are positioned such as to be spaced above the board 108 (
It will be appreciated that the manner of mounting the mic assemblies 100 with suspension elements 34 described above serves to isolate the mics so that they exhibit superior acoustic performance. Other equivalent structural mounts would include a rubber or elastic suspension ring with attachments points for the microphones.
Turning now to the embodiment illustrated in
The shock cords 34 are preferably an elastic material such as rubber. In the preferred embodiment there are 4 posts 36, each associated with an attachment point 104 on the enclosure 102.
Although the embodiment shown in the drawing includes four posts 36 and associated attachments points 104 and shock cords 34, each of which defines a mic assembly suspension attachment means, a greater or lesser number of such suspension attachment means will suffice to suspend the mic assembly 100 over the board 108 with a space 112 therebetween.
From the drawings it will appreciated that each microphone assembly 100 is at all times suspended over the board 108 so that it is isolated from the board and such that the only interconnection between the microphone assembly and any other structure is with the shock cords 34 and necessary electrical connections, if appropriate.
Reference is now made to
The boundary microphone assembly 10b is located intermediately on the conference table 120 and incorporates four microphone assemblies 100. These four microphone assemblies 100 are angularly oriented so that they point at participants 122b, 122c, 122g and 122h, respectively. The boundary microphone assembly 10c that is located furthest from display 124 and incorporates three microphone assemblies 100 of the type described above. These three microphone assemblies 100 are oriented so that they point at participants 122d, 122e, and 122f.
As noted above, the hub 14 and suspension ring 12 described in respect of
While the present invention has been described in terms of preferred and illustrated embodiments, it will be appreciated by those of ordinary skill that the spirit and scope of the invention is not limited to those embodiments, but extend to the various modifications and equivalents as defined in the appended claims.
| Number | Date | Country | |
|---|---|---|---|
| 62681145 | Jun 2018 | US |
