A microphone is a device that converts acoustic energy into electric energy. They utilize a moving surface or diaphragm to detect audio waves that pass through the microphone. The output is generally proportional to the amplitude or overall volume at which the audio wave first reaches the microphone. Throughout this chapter I'll share audio examples of each type of microphone. I want you to listen closely throughout the examples

Dynamic mics - The dynamic microphone is based on a magnetic moving coil called a diaphragm. The way these work is when a sound wave passes through the diaphragm, it causes the coil to move within its magnetic field, which generates an electric voltage. High frequency sound waves carry less energy, making it harder for them to move the heavier diaphragm of a dynamic microphone. The direct result is a limited response in the upper frequencies. They typically don't require external power for operation. Dynamic microphones have a uni-directional cardioid pickup pattern, and are commonly used on sources such as drums, vocals, and electric guitars, because they can handle very high sound pressure levels. Because they're highly durable and can withstand high gain before feedback, they're well suited for use in live sound. Now I'll list some of the most recognizable dynamic microphones. The Shure SM57 is commonly referred to as the workhorse, and was first introduced in 1965. You have most likely seen them used on snare drums and guitar amps in both live and studio use.

Condenser mics - A condenser microphone is based around a circular plate that's called a diaphragm. They come in both small and large diaphragms. As a sound wave passes through the diaphragm, it causes a vibration which creates an electrical voltage. Their high sensitivity make them great on quiet sources. Condenser microphones are commonly used on vocals and acoustic instruments because of their wide frequency response as well as their excellent ability to capture mid and high frequency detail. They require external power to operate which is either by 48 volt phantom power for solid state designs or a dedicated power supply for tube designs. Condenser microphones can be configured with a variety of polar pick up patterns. Some have a fixed cardioid pattern and others have a switchable option that can take it from cardioid to bidirectional and all the way to omnidirectional. Let's take a look at some of the most recognizable condenser microphones. The Neumann U 47 and U 48 tube microphone is probably the most famous vocal microphone

Ribbon mics - A ribbon microphone works similarly to a dynamic microphone. It uses a very thin metal ribbon that is stretched between two very powerful magnets. The ribbon vibrates when a sound wave hits it, and like the dynamic coil, it creates an electrical voltage as a result. Ribbons typically don't require any sort of power to operate, but there are a few existing models that do require 48 volts. It's always recommended to refer to the operation manual before applying any sort of power to a microphone if you're not completely certain that the particular model requires it. Ribbon microphones typically have a fixed bi-directional polar pattern, although there is exceptions to this. They're also very sensitive to high sound pressure levels, so care must be taken not to place them too close to loud sources, as the ribbon may tear. Here are some of the most recognizable ribbon microphones. The RCA 44-BX is the oldest microphone that'll be discussed in this course. It was introduced in 1932 and was specifically designed for broadcast use. Engineers became fond of ribbon mics because of their smooth and rich tonal characteristics. In 1976, RCA had unfortunately closed their microphone department. Currently, the Los Angeles based company, AEA, is manufacturing what they refer to as a museum-grade reproduction of the RCA 44. The RCA 77-DX was introduced in 1954, and offered a multi pattern selector that would allow for cardioid and omnidirectional patterns in addition to the typical bidirectional pattern. The way in which this microphone switches between the directional patterns is very interesting. It utilizes a rotating shutter that closes the opening behind the ribbon element. With the shutter wide open, the microphone operates in bidirectional mode, and when it's fully closed, it operates in omni. The in-between setting activates cardioid mode. The Beyerdynamic M one 60 has a unique lollipop-shaped body that was introduced in 1952. This microphone utilizes a double ribbon design, and has a fixed hyper-cardioid polar pattern. Andy Johns created history when he put two M one 60s at the top of the stairwell at Headley Grange and fed them into a pair of ADR Compex Limiters and a Binson Echorec Unit to achieve the monstrous drum sound that can be heard on Led Zeppelin's "When The Levy Breaks." The Coles Electro-acoustics 4038 was introduced in 1953, but was originally released by a company called STC, which stood for Standard Telephones and Cables. The founders of Coles worked for STC as toolmakers, and then, in 1972, began manufacturing their microphones for them. In 1974, STC gave up on marketing those products. Coles stepped in and bought all of the manufacturing rights and patents. The 4038 is still in production today. The Royer Labs R one 21 is the newest microphone that's mentioned in this course. It was introduced in 1998 with an aim to reintroduce the ribbon microphone in a new way. Their special new design offered the same characteristics that engineers love, but in a package that was much more practical. The R one 21 comes in a small, but extremely durable shell. It can also handle extremely high sound pressure levels, making it virtually indestructible and perfect for loud sources such as electric guitars and drums. They're so confident in their design that they offer a lifetime warranty on their products. So, those are some of the most common ribbon mics that you might find in a recording studio.