Microphones The Basics

The microphone is your primary tool in the sound chain from sound source to audio storage medium. Each microphone has its own sonic characteristics which means that it is important to pick the right microphone for the job.

Factors when capturing a sound with a microphone: A microphone’s location in relation to the sound source; The acoustic environment in which we choose to record the sound source

We will just be using dynamic and condenser microphones. Types of Microphones There are three main types of microphones: 1) Dynamic 2) Ribbon 3) Condenser We will just be using dynamic and condenser microphones.

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 (I won’t ask you to know this… )

Dynamic Microphone Advantages: durable and can withstand a lot of volume before they distort (within their own circuitry). they don’t require phantom power to operate. 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) snare drums, guitar amplifiers, kick drum, vocals and any instrument that can play loud.

Disadvantages: These microphones often miss the many subtle nuances of sounds because it takes a lot of sound pressure to move the coil. In other words, they are not as sensitive as condenser microphones.

3) Condenser 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 microphone advantages: they respond to fast attacks and transients 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 microphones typical uses: recording studios can be used to record almost any sound…except very loud ones (ex. Kick drum) extremely effective with quiet sounds the perfect choice for capturing room ambience. almost always used for vocals, acoustic guitars and drum overheads.

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) require phantom power to operate

Microphone polar patterns: A polar pattern is describe the way a microphone picks up sound. Different microphones pick up sound from different directions. There are three main types of patterns: 1) Cardioid 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 (Hz). 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.

Conclusion Effective sound miking requires lots of experimentation. Most home studios should have at least one good dynamic mic and one good condenser mic.