Correct Positioning Of a Microphone

BACKGROUND

IntriCon offers a wide range of high quality microphones with different polar responses such as Omni-Directional, Uni-Directional (Super/Cardioid) and Bi-Directional (Noise-Canceling) designed to meet the requirements and challenges of different applications. However, in order to reap the optimal microphone acoustic performance such as signal-to-noise ratios (S/N), voice quality or acoustic gain before feedback, it is critical that the user positions the respective microphone in the correction locations relative to the user's lips. Below is a guide as to how each type of microphone should be positioned.

 

For Bi-Directional (Noise-Canceling) Microphone

For a Noise-Canceling microphone to work optimally, especially in a high noise environment, the microphone port (TALK side) must be positioned DIRECTLY in front and facing the lips. Not off to one side, not to the corner, not below or above the lips.

This figure illustrates the ideal positioning of the microphone. This will provide the best voice pickup and best noise rejection performance.

As the microphone element is placed right in front of the mouth’s air stream when the person talks, a windscreen must be used in order to reduce plosives (pops) like “b” and “p”.

Often, noise-cancelling microphones are used in voice recognition applications. Some voice recognition engines are very sensitive and may have problems dealing with plosive sounds, resulting in errors.

If really needed, a compromise will be to position the microphone closer to the corner of the lips (but not away!). Any position further from the lips will result in a loss of voice pickup. Again, a windscreen should always be used.

Whether the microphone is positioned right in front of the lips or cloaser to the corner, the distance between the microphone port and the lips should not be more than a ¼”.

Any distance more than a ¼” will result in compromising the noise-cancelling performance of the microphone.

 

 

For Uni-Directional (Super/Cardioid) Microphone

For a Uni-Directional microphone to work optimally, the microphone port (TALK side) should preferably be positioned in front and facing the lips.

This figure illustrates the preferred positioning of the microphone. This will provide the best voice pickup and best noise rejection performance.

As the microphone element is placed right in front of the mouth’s air stream when the person talks, a windscreen must be used in order to reduce plosives (pops) like “b” and “p”.

In situations where the user feels uncomfortable in placing the microphone right in front of the mouth, or if the boom is too short to allow the microphone element to reach all the way to the front of the lips, a compromise will be to position the microphone right at the corner of the lips, as the figure on the left illustrates. But ensure that the microphone port is facing the lips.

Again, a windscreen should always be used.

Whether the microphone is positioned right in front of the lips or at the corner, the distance between the microphone and the lips should not be more than a 1".

Any distance more than a 1” will result in compromising the performance of the microphone.

Do note that like any other directional microphone, it will have similar proximity effect, where there'll be more low frequencies (bass) when the microphone is closer to the lips (and less when it's further away).

 

For Omni-Directional Microphone (on a boom)

Adjust the flexible boom so it follows the contours of your face. Position the microphone tip about 1cm to 2cm from the corner of the lips. Generally it can be between 1cm to 4cm from the corner of the mouth, but this will depend greatly on:

1) the user's ability to project his or her voice. If the user is a softspoken person, the microphone needs to be positioned closer to have better S/N and better gain before feedback (in cases where sound reinforcement systems are used).

2) the user’s head profile and the distance between the ear to the lips. On certain users, the boom arm may not be long enough to position the microphone all the way to the corner of the lips.

Avoid placing microphone too close to the nose as the output will sound nasal!

BAD!

OK!

GOOD!

BAD!

OK!

GOOD!

 

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