Sound
Friday, October 30th, 2009Microphones are thought to be the most critical part of the audio chain and need careful attention when they are used. People often make the mistake of asuming setting up the microphone is easy when it isn’t and choosing the incorrect microphone. A good quality microphone is the key for excellent audio.
There are several different types of microphones, each suited for different purposes and choosing the correct one is very important. Things to consider -
- Directionality
- Frequency Response
- Impedance
- Handling Noise
It is best to try the different microphones first, to show which one creates the sound you are wanting.
The most important part of microphone placement is distance. This usually means putting the microphone as close as possible to the subject without introducing unwanted effects. The audio becoming bassy, distorted and popping would usually mean the microphone is too close. Using more than one microphone can also cause problems with phasing or cancellation such as in an interview. You need to be wary of this.
Microphones can cause many problems if they are not mounted or held properly. They should always be positioned correctly so it won’t fall over, get wet, shielded from unwanted noise and cables safe. You can use stands, clamps, clothing clips and head sets to mount microphones, however, some are more suited than others.
You must never blow into a microphone or tap the head. Also, if the performance of a mic deteriorates over time, it will possibly have to have the diaphragm cleaned.
Audio Monitoring & Metering
Audio metering is the visual display used to monitor audio levels. There are two common types of meter which are used to measure audio levels:
- VU meter (volume unit) – used to measure the loudness of an audio signal. It is developed to represent the way the human ear hears the volume.
- PPM meter (peak program) – Similar to a VU meter but is faster, which makes it easier to measure. Useful for when pops and distortion exist.
Both types of meter are available in various forms including stand-alone units, components in larger systems, and software applications. Whatever the type of meter, two characteristics are important:
- The scale
- The ballistics