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AV Insight
March/April 2009
Microphones: The first link in the audio chain
By Ralph Niekamp
A crucial aspect of any meeting or event is audio intelligibility. Delegates need to be able to hear the message and exchange ideas. While there are many different types of audio systems, microphones are the first important component. If the proper microphone is not selected, the performance of all other audio components will be diminished.
What microphone is best depends on the application. The most commonly used microphone is the dynamic, cardiod microphone. These microphones are relatively affordable and durable. This style of microphone is a good choice when the microphone is treated roughly (think of a young Roger Daltrey swinging his microphone in a circle above his head) or when there is a high level of ambient room noise. The tight “cardiod” pickup pattern only picks up sound that is directly in front of the microphone and not the ambient room noise.
A lavaliere microphone is appropriate for a presenter that needs to have their hands free and a wireless lavaliere microphone enables them to walk around the stage. These also require care during set up. The presenter needs to understand the appropriate attire and microphone placement so that the microphone can pick up the presenter’s voice effectively and not produce distracting noises.
A lavaliere microphone should be placed directly under the chin but not so close that it can be bumped by the person’s movements. As the microphone is pointing up, feedback loops with house sound system speakers directly above the microphone can be created. A sound check is essential so that any problem areas are identified before the presentation.
Condenser podium microphones can be an excellent choice when a podium is being used as the focus of the presentation. These unobtrusive microphones generally have a small microphone on a 12” to 18” gooseneck, mounted to the podium. This feature makes a condenser podium microphone a good choice when image magnification or photography will be part of the event.
While they are available in varying pickup patterns, they generally have a much larger pick up area than a cardiod dynamic microphone and a wider frequency response. A presenter still needs to face toward the microphone but they can move their head side-to-side and still have their voice reproduced evenly. The wider pick-up pattern also means that different presenters do not have to adjust the microphone as they reach the podium.
Pressure zone microphones (PZM) are commonly used in boardroom videoconferencing and teleconferencing applications. These flat microphones are placed on a table, picking up any sound waves that contact the table surface. This enables one streamline microphone to capture the conversations around a table. While different pickup patterns are available, PZM microphones are generally omni-directional.
Conference microphone systems are popular. They consist of a conference chair console and multiple delegate stations. They all have a condenser microphone and gooseneck mounted to the chair console and delegate stations. The console and stations have a built in loud speaker and volume control. When a station’s microphone is activated the internal station’s speaker is muted, to control feedback. Many systems offer additional features such as a red light to signal that the microphone is active, headphone outputs, integration with simultaneous interpretation systems, cough muting, and voting functions. Some systems include features such as auto voice recognition and noise cancellation.
A conference microphone system allows the conference chair (or assistant) to control all of the microphones. The conference chair system console can turn any of the microphones on and off. The conference chair can override at any time and take the floor. Many of the conference chair consoles utilize touch screen technology with the touch screen set up to mirror the set up of the room. Some conference microphone systems include computer software that control many of the system operations and allow for expansion in the number of delegate stations.
All of the above microphone systems are available in a wired or wireless format. Most of the microphones are available with different pickup patterns and some microphones have selectable pickup patterns.
Consult your AV professional before your next event and ensure that your microphone system will enable all of your participants to take home the message.
Ralph Niekamp, Inland AV Saskatoon General Manager addresses audiovisual considerations important to event planners. As a branch manager, Niekamp brings a unique perspective as he is involved in both permanent systems design and integration and AV rentals applications.
Filed under: The Industry
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