The Basics Of Lavalier & Headworn Microphones

Two widely used microphone types, and tips on how to use them with maximum effectiveness

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Lavalier Microphones
The desired sound source for a lavalier microphone is a speaking (or occasionally singing) voice.

Undesired sources include other speaking voices, clothing or movement noise, ambient sound, and loudspeakers.

Balanced low-impedance output is preferred as usual. Adequate sensitivity can be achieved by both dynamic and condenser types, due to the relatively close placement of the microphone.

However, a condenser is generally preferred. The physical design is optimized for body-worn use. This may be done by means of a clip, a pin, or a neck cord. Small size is very desirable.

For a condenser, the necessary electronics are often housed in a separate small pack, also capable of being worn or placed in a pocket. Some condensers incorporate the electronics directly into the microphone connector.

Provision must also be made for attaching or routing the cable to allow mobility for the user.

Placement of lavalier microphones should be as close to the mouth as is practical, usually just below the neckline on a lapel, a tie, or a lanyard, or at the neckline in the case of robes or other vestments.

Omnidirectional types may be oriented in any convenient way, but a unidirectional type must be aimed in the direction of the mouth.

Avoid placing the microphone underneath layers of clothing or in a location where clothing or other objects may touch or rub against it. This is especially critical with unidirectional types.

Locate and attach the cable to minimize pull on the microphone and to allow walking without stepping or tripping on it. A wireless lavalier system eliminates this problem and provides complete freedom of movement.

Again, use only high-quality cables and connectors, and provide phantom power if required.

A condenser lavalier microphone will give excellent performance in a very small package, though a dynamic may be used if phantom power is not available or if the size is not critical.

Lavalier microphones have a specially shaped frequency response to compensate for off-axis placement (loss of high frequencies), and sometimes for chest “resonance” (boost of middle frequencies).

The most common polar pattern is omnidirectional, though unidirectional types may be used to control excessive ambient noise or severe feedback problems.

However, unidirectional types have inherently greater sensitivity to breath and handling noise. In particular, the consonants “d”, “t”, and “k” create strong downward breath blasts that can result in severe “popping” of unidirectional lavalier microphones.

Placing the microphone slightly off to the side (but still aimed up at the mouth) can greatly reduce this effect.

Good techniques for lavalier microphone usage include:
• Do observe proper placement and orientation.
• Do use pop filter if needed, especially with unidirectional.
• Don’t breathe on or touch microphone or cable.
• Don’t turn head away from microphone.
• Do mute lavalier when using lectern or altar microphone.
• Do speak in a clear and distinct voice.

Headworn Microphones
Again, the desired sound source for a headworn microphone is a speaking or singing voice.

Undesired sources include other voices, instruments, ambient sound and sound system loudspeakers.

Most headworn microphones are of the condenser type because of their small size and superior sound quality. A dynamic type can be used for speech-only applications or if larger size is not an issue.

For either type, the frequency response is shaped for closeup vocal with some presence rise.

An omnidirectional polar pattern is suitable for most applications, especially if the microphone does not reach all the way in front of the mouth.

A unidirectional pickup is preferred in very high ambient noise applications or to control feedback from high volume monitor loudspeakers.

For proper operation, unidirectional types should be positioned in front of or directly at the side of the mouth and aimed at the mouth. A windscreen is a necessity for a unidirectional headworn microphone.

Headworn designs put the mic element very close to the voice.

Balanced low-impedance output is preferred for hardwired setups but headworn types are often used in wireless applications. In that case, the impedance and wiring are made suitable for the wireless system.

For condenser types, the bodypack transmitter provides the necessary bias voltage for the microphone element.

There are many different headworn mounting designs. Most have a headband or wireframe that goes behind the head, while a few are small enough that they merely clip over the ear.

In all cases, the microphone element is at the end of a miniature “boom” or flexible arm that allows positioning close to the mouth. Again, an omnidirectional element can be positioned slightly behind or at the side of the mouth while the unidirectional type should be at the side or in front and aimed toward the mouth.

The main advantages of the headworn microphone over the lavalier are greatly improved gain before feedback and a more consistent sound level.

The increase in gain before feedback can be as much as 15-20 dB. This is completely due to the much shorter microphone-to-mouth distance compared to lavalier placement. The headworn can nearly rival a handheld type in this regard.

In addition, the sound level is more consistent than with the lavalier because the headworn microphone is always at the same distance to the mouth no matter which way the user may turn his head.

Good techniques for headworn microphone usage include:
• Do observe proper placement and orientation.
• Do adjust for secure and comfortable fit.
• Don’t allow microphone element to touch face.
• Do use pop filter as needed, especially for unidirectional.
• Do adjust vocal “dynamics” to compensate for fixed mouth-to-microphone distance.

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