4. Sound, Analogue and different Mic types.

What is Sound:

Watkins says that “sounds are airborne vibrations that are caused by an action and then travel from the source of the vibration to the the ear.” (Watkin, 2002 :p2 )

Analogue and digital signals:

Analogue is a continuous signal or value  which are represented in an electrical waveform whereas digital signals are represented by separate values.

Analogue to digital conversion is turning a continues signal into numbers which is represented on a scale using bit and sample rate. (Watkins, 2002:p 3)

Higher sample rate results in better quality audio and needs to be high to give an accurate representation of the bite rate.

Screen Shot 2017-03-22 at 23.26.02
Example: (AVV lecture slide; 2017)

Microphones:

Microphones detect sound vibrations and record them as digital information. They convert acoustical energy , sound waves, into electrical energy. Microphone picks up sound from different directions depending on the heads.

Screen Shot 2017-03-14 at 10.34.59
How Microphones work (AVV lecture slide)

Different mic types:

Omnidirectional-  Pick up sound from all directions. Not ideal for location interview; can pick up unwanted sound. But good effect mic’s which can be used to capture ambient sound.

Screen Shot 2017-03-22 at 23.42.13
(AVV lecture; 2017)

Bidirectional- Sensitive to sound in a figure of eight pattern and are usually found in radio studios like the BBC.

Screen Shot 2017-03-22 at 23.32.41
Bidirectional mics used in the radio studio.
Screen Shot 2017-03-22 at 23.33.57
(AVV lecture slides; 2017)

 

 

 

 Alicia and James are speaking into a Bidirectional Mic. Pete explains how sound changes when Alicia is further away from the mic. Her voice become thin and light appearing off-mic. Within my own package i would seat my guest directly opposite so that audio is recorded in equal quality. 

Cardioid – Heart shaped microphones where sound is mainly picked up from the front and to the lesser extent the sides as well. These microphones are versatile and ideal for location interview or voiceovers.

Screen Shot 2017-03-22 at 23.50.59
(AVV lecture; 2017)

Hyper-Cardioid- Very Directional,eliminates sound from sides and rear. Good to use in my own podcast to commentary within noisy locations such as  football matches or university campuses.

Condenser mic- require power from batteries or external source. More sensitive then dynamic mics so prone to distort. Not great for high volume but good for capturing subtle sound.

Screen Shot 2017-03-22 at 23.53.38
(AVV Lecture; 2017)

 

Plosive sounds:

When presenters and radio guest speak to close to the microphone plosive sounds appear when the letters’P’ and ‘B’ are used. Paul says “this is because of the  sudden rush of air emitted from the mouth of such occasions.” (Paul,2003: p114) This is easily avoidable in my own podcast by placing pop-shields over mics.

References

Chantler, P. and Stewart, P. (2013). Basic radio journalism. 1st ed., Oxford [England]: Focal Press, p.144.

Watkins, J. (2002). An introduction to digital audio. 2nd ed.,Burlington[England]: Focal Press, p2

Watkins, J. (2002). An introduction to digital audio. 2nd ed.,Burlington[England]: Focal Press, p3.

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