Omnidirectional Microphone

Support for Omnidirectional Microphones

An omnidirectional microphone has a response which is equal to one in all nonbaffled directions. The `phased.OmnidirectionalMicrophoneElement` object enables you to model an omnidirectional microphone. When you use this object, you must specify these aspects of the microphone:

• The operating frequency range of the microphone using the `FrequencyRange` property.

• Whether the response of the microphone is baffled at azimuth angles outside the interval [–90,90] degrees using the `BackBaffled` property.

Backbaffled Omnidirectional Microphone

Construct an omnidirectional microphone element having a response within the human audible frequency range of 20 to 20,000 Hz. Baffle the microphone response for azimuth angles outside of +/- 90 degrees. Plot in polar form the microphone power response at 1 kHz.

Note: This example runs only in R2016b or later. If you are using an earlier release, replace each call to the function with the equivalent `step` syntax. For example, replace `myObject(x)` with `step(myObject,x)`.

```freq = 1e3; microphone = phased.OmnidirectionalMicrophoneElement(... 'BackBaffled',true,'FrequencyRange',[20 20e3]); pattern(microphone,freq,[-180:180],[-90:90],'CoordinateSystem','polar','Type','power');```

In many applications, you sometimes need to examine the microphone directionality, or polar pattern. To obtain an azimuth cut, set the elevation argument of the `pattern` method to a single angle such as zero.

`pattern(microphone,freq,[-180:180],0,'CoordinateSystem','polar','Type','power');`

To obtain an elevation cut, set the azimuth argument of the `pattern` method to a single angle such as zero.

`pattern(microphone,freq,0,[-90:90],'CoordinateSystem','polar','Type','power');`

Obtain the microphone magnitude response at the specified azimuth angles and frequencies. By default, when the `ang` argument is a single row, the elevation angles are 0 degrees. Note the response is unity at all azimuth angles and frequencies, as expected.

```freqs = [100:250:1e3]; ang = [-90:30:90]; response = microphone(freqs,ang)```
```response = 7×4 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ```