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Microphones are devices used to convert acoustic energy to electrical energy. There are several things to consider when selecting which microphone to use in any given situation. There are several considerations to make when choosing a microphone. Firstly the design/type itself (i.e. is it built for what you want to do) a very expensive highly sensitive Condenser microphone normally mounted in a shock stand would probably not last very long as a live microphone due to being handled all the time. Polar Pattern should be taken into account as you want to be able to pick up what you want with as little as possible background interference. The frequency response is very important as this tells you at what level the microphone will pick up certain frequencies. Impedance should also be checked as if a microphone is connected to an input with a lower impedance this will result in a loss of signal strength.

Types of Microphone Microphones for Studio UseMicrophones for Live UseMicrophones for Broadcast Use

Microphones

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Dynamic Microphones

Condenser Microphones

Capacitor Microphones (referred to commonly as a condenser microphone) it use capacitance to convert acoustical energy into electrical energy. It has four main components a floating metal plate, a fixed metal plate, a preamplifier and a power supply. Similarly to the dynamic microphone changes in sound pressure are used to move the diaphragm however in this type of microphone the diaphragm is a floating metal plate. Combined with the back plate this forms a capacitor which stores electrical charge. When the floating plate is moved the capacitance is altered this changes the electrical charge of the circuit thus converting acoustic energy to electrical energy. Due to the high impedance of the circuit the pre amplifier is required to send the signal through the cable and for this a power supply is required. Condenser microphones are very sensitive which make them good for recording quiet instruments such as acoustic guitar.

Dynamic Microphones convert acoustic energy to electrical energy via mechanical movement. It comprises three main components a diaphragm, a moving coil of wire and a magnet. As sound is directed toward the microphone changes in sound pressure cause the diaphragm to move backwards and forward. As this happens the coil is moved in and out of a magnetic field creating electrical current that is analogous to the sound pressure exerted upon the microphone. Dynamic microphones are generally very sturdy and are used a lot in live sound as they are unlikely to get damaged.

Types Of MicrophoneRibbon Microphones

Ribbon Microphones similar to a dynamic microphone made up of a flexible corrugated aluminium ribbon, which acts as the diaphragm, and a permanent magnet. Again as sound pressure changes the ribbon moves backwards and forwards within the magnetic field inducing a current which again is analogous to the sound pressure. It has very low impedance so a transformer is used to drive the signal through the cable. An advantage of a ribbon microphone over a condenser microphone is they don’t suffer from proximity effect (sometimes referred to as “bass tip up”).

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AKG C 414 XL II

Type: Condenser

Polar Pattern: Switchable(Omnidirectional, wide cardioid, hyper cardioid, Figure of 8

and 4 intermediate settings)

Frequency Response: 20Hz – 20KHz

Sensitivity: 20 mV/Pa (-34 dBV) +/- 0.5dB

Frequency Response Diagram:

Varies between polar patterns information on Manufacturers Website

Studio Microphones

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Shure SM58

Type : Dynamic

Polar Pattern: Cardioid

Frequency Response: 50 Hz - 15 kHz

Sensitivity (1 kHz): -54,5 dBV/Pa / 1,88 mV/Pa

Frequency Response Diagram:

Audio samples available on manufacturers website

Live Microphones

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CharterOak S700

Type: Condenser

Polar Pattern: Cardioid

Frequency Response: 20Hz-20KHz

Sensitivity: 16mV/Pa 94dB=1V/Pa@1kHz

Frequency Response Diagram:

Further information available on Manufacturers Website

Broadcast Microphones

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Loudspeakers operate the opposite way around from a microphone converting electrical energy into acoustic energy. This is achieved by passing the current through a coil of wire that is surrounded by a permanent magnet and attached to the speaker cone. As the current passes through the coil this affects the magnetic field around it causing the coil and therefore the speaker coil to move generating sound. When deciding what speaker to use we need to look at the design of the speaker ( is it suitable for live use and moved around due to a rugged plastic housing or more useful as a studio monitor in a static place as its made of easily damaged wood?). Frequency response should be looked at to ensure the speaker can reproduce everything you need it to. The sensitivity of the speaker at what level will sound become distorted?, Impedance again if this is mismatched to the input signal strength will be lost and dispersion angle will the speaker cover the necessary area sufficiently.

Loudspeakers for Live ApplicationsLoudspeakers for Studio Applications

Loudspeakers

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Function-One F88

Frequency Response:70Hz-18Khz

Sensitivity:99dB SPl @ 1W 1M

Dispersion Angle: 110° x 40°

This speaker could be used as part of a sound reinforcement system or as part of a sound system in a bar/club.

More information can be found on the Manufacturers Website

Tannoy VQNET 60 Live

Frequency Response: 90Hz- 27KHz

Sensitivity: LF 134dB@ 1M / HF 134dB@ 1M

Dispersion Angle: 60° conical.

This type of speaker would be more suited to use as part of a live sound system installation but could also transported and used as a portable PA.

More information can be found on the Manufacturers Website

Loudspeakers for Live Applications

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Genelec 1035B

Frequency Response: 30Hz-20Khz +/- 2.5dB

Sensitivity 131dB SPL @ 1M

No dispersion angle detailed as this is a monitor

speaker and should only be used within a room

and the listeners no more than a few meters away.

Full information available on Manufacturers Website

Loudspeakers for Studio Applications

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Amplifiers

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Mixing Consoles

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Signal Processors

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Software

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Cardioid Hyper CardioidNarrower pickup field and could be used to ignore background noise however a side effect of this is a small area of pickup to the rear. This can also

This pattern it generally has a wide pickup area and is commonly found on standard Dynamic and Condenser microphones

Polar Pattern

Omnidirectional Picks up all sound around the microphone

BidirectionalAlso known as Figure of 8. Picks up sound in front and behind the microphone

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http://www.mediacollege.com/audio/microphones/how-microphones-work.html

http://www.shure.co.uk/products/microphones/sm58

http://www.akg.com/site/products/powerslave,id,1129,pid,1129,nodeid,2,_country,EN,_language,EN.html

http://charteroakacoustics.com/products_s700_details.htm

http://micro.magnet.fsu.edu/electromag/java/speaker/

http://www.funktion-one.com/products/f88/

http://www.tannoypro.com/#Page=Product&Id=92.350

http://moodle2.stow.ac.uk/course/view.php?id=36

References

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