Todd Messer, my guest from Episode 6, joins us again to discuss microphones in specific detail. Todd discusses the types and uses of microphones with me and gives helpful tips on things to consider with microphone setup.
Microphone Physics
There is a lot of physics involved in microphone construction.
It is important to understand transducer types when dealing with microphones. A transducer takes one form of energy and changes it into a different form of energy. In microphones, there two primary types of transducers: acoustic and electrical.
- Dynamic: Acoustic energy moves a core in a coil inside the microphone generating electrical signal. Dynamic microphones tend to be less expensive and very sturdy.
- Condenser: A capacitor inside the microphone converts sound to electric signal; a power source is necessary for this type of microphone. Tend to be more fragile and breakable.
Most cheaper microphones are dynamic microphones. They have a much simpler design and construction and subsequently cost less.
Dynamic microphones are not as sensitive. Often, because they are less sensitive, speakers must “kiss the mic” meaning their lips are actually touching the microphone as they speak. If there is too much distance between the speaker and a dynamic microphone, it might not be able to pick up the vibrations necessary to work properly.
With a dynamic microphone, using a compressor might be advisable. The compressor will help to limit enormous volume fluctuations and variations.
Aspects of Microphones
Microphone Pickup Patterns
Where is the microphone designed to pick up sound?
- Unidirectional - Sure SM58 is a unidirectional microphone. If you stay close and directly in front of the microphone, there will be good sound pickup. If you turn to the side, top, bottom, or off the axis of the microphone, the sound drops off.
- Bidirection - Sound is picked up in front of and behind the microphone. This type of pickup pattern is useful in an interview setting, where two opposite parties require projection.
- Omnidirectional - Sound is picked up in a semi circle configuration. This type of microphone is useful in a setting where people might be seated in a circle, with the microphone centered in the circle.
Wired versus Wireless Microphones:
Wired Microphone:
It is best to use a wired microphone whenever possible.
Wireless Microphone:
With a wireless microphone, you need to keep track of batteries and charge equipment.
Some frequency patterns for wireless microphone setups are actually illegal to use in proximity to, say, an airport or other such facility. Be aware of these sorts of laws and requirements for your geographical area when setting up your sound system with microphone frequencies.
Some setups have the ability to host microphones on different channels, even if they are of the same frequency.
Earset versus Headworn Microphones:
Earset microphones are worn on one ear and are potentially lighter weight than headworn microphones.
Headworn Microphones involve hooking mechanisms on both ears, making them more stable and less likely to need adjustment when worn for a longer period of time.
Where do you place a microphone?
This involves a lot of common sense. Consider the following:
- What is making noise nearby?
- What is the shape/acoustic quality of the room?
- Does the room echo?
- Are the acoustics such that sound does not carry, that the sound just dies?
Beware of magnetic clashing with microphones which causes the sharp squealing noise.
Microphone Tips:
- May need to use a compressor to keep the sound from blowing out.
- Sometimes the same microphone model will be available in multiple pickup patterns. Ensure that the one that you acquire is the correct pickup pattern to suit your needs.
- Maintenance of microphone equipment involves keeping it clean and storing it at a good temperature and humidity.
- For loose sound system cords that need to be temporarily secured, gaffers tape is highly recommended.
