Neal Hall, Ph.D., Electrical and Computer Engineering Michael Kuntzman, Ph.D., Knowles Corporation Donghwan Kim, ME Karen Kirk, Mechanical Engineering Nishshanka Hewa-Kasakarage, have come up with directional microphones employing innovative designs in sensing sound. It senses sound with high sensitivity in preferred directions while being insensitive to sound in other directions. Directional microphones are used in hearing aids, for example, to avoid the typical “cocktail party” problem. Directivity enables a hearing aid wearer to listen to a speaker of interest with high sensitivity while rejecting ambient background noise that would otherwise degrade speech intelligibility.
The usefulness as well as utility gained by the users of some consumer electronic products, such as tablets, laptops, and smartphones among others have been enhanced by the MEMS microphones. This particular kind of receivers have high rates of performance and are small size making them ideal for use in the portable electronic gadgets, including the above mentioned. For these microphones, their sound inlets are designed in such a way that they are not in direct with the external surrounding. Due to this, its design has been able to come up with an acoustic path from the eternal surrounding permitting the sound to get to the microphone. The designation of this kind of acoustic path can significantly influence the overall effectiveness of the system.
All the underlying components of both the external and internal environment as well as the thin layer of the microphone, membrane, guide the wave thereby shaping the entire response of the frequency. Among these components include the gadget housing, the acoustic machine, the PBC and the microphone itself. The materials used during the creation of the sound path are selected and modified in a way that they create they positively affect the frequency response.
To better as well as design the acoustic gadget in such a way that it performs to the required standards; it requires that the acoustic path be modeled in the most desired way. Other than the modeling of the acoustic path, the frequency response has to be stimulated by the use of a professionally designed tool, and in this case COMOSOL is commonly used.
Along the upper part of the empty bottle, the sound is produced by use of a hollow cavity. This hole is made up of a narrow sound inlet that resonates in an acoustic design whenever excited. It is known as a Helmholtz resonator, which makes use of various resonate frequencies for the identification of the frequency components within music and similar complex sounds.