Ears are better than microphones, so…

February 21, 2008 at 4:01 am 2 comments

One of the questions we are frequently asked is how to mic up a room appropriately in order to record a meeting.

Well, obviously the ear is a much more complex construct than a microphone, so it is important to follow a few rules in order to get the best possible audio recording for later transcription or reference.

Placement and Directionality

The ear has the great advantage of being connected in real time to the best processing machine in the world – the human brain. As such, the ear can discriminate between the source of the sound and a reflection of it, e.g. off a wall. In fact, the brain can “focus” the ears on the source and largely exclude the reflections… amazing. So, we must be mindful of microphone placement (get it as close to the source as possible) and directionality (employ a cardioid or hypercardioid microphone).

Interference

The music industry generally follows the “Rule of Threes” which means placing the microphones so that the distance from each microphone to the source to be recorded is three times less than the distance to another source of sound. Obviously this will work best when the sources are approximately equal in intensity, but is a good rule to give you the best chance of a decent result.

Stereo vs Mono

Stereo provides a richness of sound that mono cannot provide. However, for an application like Acappella ( http://www.acappella.com.au ) stereo mics detract from the accuracy of speaker identification. So, we sacrifice a little audio “warmth” for the significant business benefit of helping the typist understand who is speaking.

External Factors

Wind, fluorescent light hum, and electrical interference can all significantly impact on the quality of an audio recording. If recording is being conducted outside, then muffs will be required. Luckily, Acappella makes allowances for hum and constant drone etc, but always be mindful of eliminating these extraneous factors if possible.

Acappella Playback Assistant

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Entry filed under: Digital Dictation, Innovation, Transcription. Tags: , , .

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2 Comments Add your own

  • 1. The Team  |  April 10, 2008 at 2:36 am

    Thanks for your comment to our blog!

    We’re quite impressed with your knowledge & information, obvious experience and careful research.
    (** Very few folks are even aware of the external factors you mention that can wreak havoc on signal quality.)

    BTW, we’re adding a link to this excellent, well-informed blog.

    The Team
    http://wirelessspeech.blogspot.com

  • 2. Den  |  June 19, 2013 at 11:29 pm

    Very useful and informative article. keep posting

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