The microphone is your primary tool in the sound chain from sound source to audio storage medium.
Factors when capturing a sound with a microphone: microphones location in relation to the sound source the acoustic environment in which we choose to record the sound source
Types of Microphones There are three main types of microphones: 1) Dynamic/Moving Coil 2) Ribbon 3) Condenser/Capacitor
1) Dynamic/Moving Coil microphones Example: Shure SM 57 They operate on a magnetic principle : movement of a copper coil around a magnet causes a changing flow of electrons that represent the sound wave
Dynamic/Moving Coil microphones Advantages: durable and can withstand a lot of volume. colours the sound in range between 5-10khz, this adds clarity, presence and understandability to many vocal and instrument sounds. doesn’t feedback as easily as other mics
Dynamic/Moving Coil microphones typical uses: mostly live situations, but they are also used a lot in the studio. close mic applications (1-12 inches) drums, guitar, vocals and any instrument that can play loud.
Dynamic/Moving Coil microphones disadvantage:These microphones often miss many sounds because it takes a lot of sound pressure to move the coil.
2) Ribbon microphones Example: Beyer M 160 a metallic ribbon is suspended between two poles of a magnet. Sound waves vibrate the metallic ribbon which causes a varying flow of electrons to the different poles of the magnet
Ribbon microphones advantages: These microphones capture a warmer and smoother sound than dynamic/moving coil microphones. Don’t feedback much in live situations.
Ribbon microphones typical uses: Typically used in the studio because they are fragile Used in close mic applications (1-12 inches) Often used for acoustic guitars. Also work well for vocals.
Ribbon microphones disadvantages: colours the sound by adding a high frequency edge fragile will only pick up sounds that are very close.
3) Condenser/Capacitor microphones Example: Audio Technica AT 4033 How do condenser microphones work? A charged electrical current is applied to a metal-coated piece of plastic. the coating vibrates sympathetically in response to a sound wave because it is very thin. The metal-coated piece of plastic is positioned close to a piece of metallic alloy. The changes in the space between the surfaces create a changing discharge of electrical current. It makes an electrical version of acoustic energy from the sound source.
Condenser/Capacitor microphones advantages: they respond to fast attacks and work more precisely than other mics and add little tonal colouration they can be used to record sounds from a greater distance and capture a broader range of frequencies big advantage: these mics record a sound while capturing natural ambience of a room.
Condenser/Capacitor microphones typical uses: recording studios. can be used to record almost any sound…except very loud ones. extremely effective with quiet sounds. the perfect choice for capturing room ambience. almost always used for vocals , acoustic guitars and drums.
Condenser/Capacitor microphones disadvantages: fairly fragile feedback too easily in a live environment (although some have low frequency roll off switches to help alleviate feedback frequencies).
Microphone polar patterns: A polar pattern is the pickup pattern of the microphone. There are three main types of patterns: 1) Cardiod 2) Bi-directional 3) Omnidirectional
Frequency Response Most microphones respond to frequencies within and beyond the human range of hearing. Our ears have the ability to hear frequencies from 20-20 000 hertz . All microphone manufacturers provide specifications for the frequency range of their products.
Frequency response curve The frequency response curve of a microphone shows how the microphone responds to different frequencies across the audible spectrum. A mic with a flat response adds little colouration to the sound. Many mics drop off sharply in the frequencies below 300 hz. Yet boast frequencies in the area of 4000 hz.
Pre-amplifiers Although a microphone can be plugged directly into a mixing board, better results are often achieved by using an amplifier.
Conclusion Effective sound output requires lots of experimentation. Most home studios should have at least one good moving coil and one good condenser mic.