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Unit 3: Sound
The basic properties of a good recording depend on what kind of recording you are doing. For notes
the most part, you want a recording with a fair dynamic range—low background noise and
clear, audible audio of the subject of your recording be it a speaker or frog calls. The basics to
remember are: selecting a good location, using the appropriate equipment and microphone, and
getting good levels.
3.7.1 selecting a Good Location
If it is possible to control where you do your recording, try to find a location that has low noise
levels and has a lockable door so people cannot walk in on you. Computers and air conditioning
with the low level hum of electricity and fans are your enemy when trying to get a good recording.
Access to a sound recording studio is, of course, the best case scenario! However, many of us
do not have access to high end recording studios and cannot completely control the location. To
some extent, this can be alleviated by using an appropriate microphone or in post when you are
editing.
3.7.2 Using the appropriate Microphone
When you buy a stereo, they say the most important component is the speakers because it is
the speakers that are actually physically reproducing the sound. For recording audio, the most
important component is the microphone because it determines what the audio sounds like when
it is recorded.
omni
The simplest microphone design will pick up all sound, regardless of its point of origin, and is,
thus, known as an omni directional microphone. They are very easy to use and generally have
well to outstanding frequency response.
Cardioid
This pattern is popular for sound reinforcement or recording lectures where class noise is a
possible problem. The concept is great a microphone that picks up sounds it is pointed at. The
reality is different. The first problem is that sounds from the back are not completely rejected, but
merely reduced in volume. This can surprise novice users. Another issue is that the microphone
will emphasize the low frequency components of any source that is very close to the diaphragm.
This is known as the “proximity effect”, and many singers and radio announcers rely on it to add
depth or “chest” to a basically light voice.
shotgun
It is possible to exaggerate the directionality of cardioid type microphones, if you don’t mind
exaggerating some of the problems. The shotgun is extremely sensitive along the main axis, but
possesses pronounced extra lobes which vary drastically with frequency. In fact, the frequency
response of this microphone is so bad it is usually electronically restricted to the voice range,
where it is used to record dialogue for film and video.
Lavaliere
The lavaliere (or lav) microphone is commonly used with wireless systems; so a speaker can move
around freely without being tied to a microphone stand or podium. The pickup range is small
and the mic is usually clipped to a shirt or lapel.
3.7.3 Different Media formats and Choices
Some of the common choices available to faculty and staff will be tape decks, mini disc recorders,
video cameras (You can still record audio to a video tape even if you do not want to use the video!)
and recording directly to a computer.
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