When speaking in front of more than a few people, you will most likely need a Public Address system to help you be heard by your audience. Considering that, one of the most important parts of that system is the microphone. This guide will try and help you understand the different types of Public Address (PA) microphones for your application.
Standard dynamic microphones convert the sound into an electrical signal. These microphones are effective when being used in close proximity situations. Dynamic microphones are popular for things such as guitars and singers where the sound source is transferred at a reasonable volume into the microphone.
Condenser Mics (also referred to as capacitor microphones) are microphones where the sound is converted into electrical signals just like with dynamic microphones. However, with condensers the difference is there is an amplifier system within the mic itself. Because of this, the condenser microphone may be better at capturing weaker sound sources. Condenser mics also need a power source such as a battery, or phantom power.
Omni-Directional refers to the pickup pattern of the microphones. OmniDirectional mics allow sound to come in from all sides. They will pick up everything in a 360 degree space or room instead of just a specific direction.
Directional Microphones, or Cardioid microphones are the opposite of OmniDirectional in that they pickup sound in a specific direction. They essentially filter out the directions that are not the focus. However, there are multiple versions of Directional Microphones that have specific uses with respect to what sounds and which directions they pickup (or ignore).
The wired microphone variety is more standard in that a physical cable will connect the microphone to the PA system. The connector usually means a clear signal, but it also can be influenced by the quality of the connecting cable itself. The sacrifice in this situation is that mobility is limited.
A wireless microphone uses RF to transmit the signal to the PA system, and the main benefit is mobility. Because these mics rely on an internal battery to transmit sound via radio waves, the number one concern is good connectivity and eliminating interference. Another point of interest is whether the PA system is a single mic system, or if other microphones can be added at a later time.
The general movement of the speaker/sound source is the biggest part of a presentation and the most important thing to consider when choosing a microphone. If the speaker will be moving around a stage, or moving with an audience, then their mobility will matter much more and you may want to consider a wireless microphone.
If you are indoors or outdoors, in a cold or warm climate, or even in front of a webcam versus inside of a large amphitheater or auditorium, these circumstances will impact your microphone choice. Knowing the environment will help you to be heard best by your audience.
If there will be multiple sound sources/speakers, then you'll need to be aware of how multiple microphones will affect each other. Also, if there are multiple microphones the chances may increase that one of them will cross a PA speaker boundary and create feedback.
For microphones that need a power source, make sure either the battery(s) are fully charged, or the phantom power source is supplying the proper voltage to the microphone.
While a class speaker or a presentation may be a lot easier on the microphone when it comes to general wear and tear, you'll need to think about how powerful some of the sound sources can be. Even though you wouldn't expect a singer to use the same microphone as a public address speaker, you could potentially see someone who is a presenter or doing the now famous TED Talks getting a bit more involved. Knowing exactly what is going on in the presentation will help you understand the needs, and durability as some microphones can be more fragile than others.
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