Usage of Microphone in Voice Recording:
Avoid using the built in microphone on any device you choose to record audio with. The microphones that are built in on most devices are of inferior quality.
There are two types: omni-directional and directional (a.k.a. cardioid). The Omni-directional microphones should be avoided, since they pick up sound in all directions which is not what you want when recording audio for transcription. What is required is that the audio recorded for transcription should have no extraneous sound in the background, and this is partially achieved using the directional microphone. A directional microphone picks up sound most clearly in the direction it is pointed while limiting the recording of other audio in the back ground. Here is a visual representation of microphone dynamics.Regardless of what device is used for recording of audio, a directional microphone can always improve the quality of the audio captured.
A Sony ECM-MS907 Stereo Microphone is a perfect choice for interviews as it gives you the option to select how directional the microphone will be 'tight' for single person interviews, 'open' for groups. (It can be bought for $80 to $100.)Another good choice for a video camera microphone is the Sennheiser MKE300. It cost about $180 and can be mounted directly onto most consumer video cameras and is considered a shotgun microphone (highly directional).
Sony ECM MS-907 microphone for transcription recording
Side view |
Top view |
It is recommend using the 90deg setting for most interviews. This will help attenuate extraneous noise.
The Placement of the Microphone
If a separate microphone is available, it is important to place it as close to the person being interviewed as possible. Microphones operate under the Inverse-Squares rule. Simply stated, every doubling of the distance reduces the sound level by a power of 2. Thus a speaker 4 feet from the microphone will only be 1/4 as loud on the recording as the same speaker 2 feet from the microphone. It is recommended that the microphone should be directly placed in front of the person talking, no more than 2 feet away. And make sure to point the microphone directly at the person talking.
‘Quiet’ Recording Environment:
The audio should be recorded in a quite environment, recording the interviews in a crowded public place is not an ideal choice, sometimes background noise is over looked , for example an air conditioning unit functioning or the traffic down the road, it can all add to the background disturbances, which can be avoided.
The mind eliminates the extra sound while recording on location, but the microphone is a sensitive device, and it will capture all the sound. On a live recording, everything that is said by the speakers can be understood, however once you hear the tapes later, it becomes difficult because the recording will have multiple sounds and to filter out the speakers voice from what is recorded becomes an uphill task.If it becomes necessary to record in a public place, where the background sound is going to be a hindrance to your recording, place the microphone as close as possible to the speaker, preferably fix it to the collar of the speaker or hold it a few inches away from the mouth of the speaker, you may have observed how close the TV news reporters hold the microphone to the person they are speaking to, it sometimes appears that they would not hesitate to insert the microphone into the speakers mouth, if the noisy environment around required them to do so. It helps to hear the speaker loud and clear
