Choosing stage microphone
Microphone is the first and probably the most important element in the audio chain, which is responsible for the transmission of our voice and music to the audience. There are literally hundreds of microphones on the market, so choosing the right one for us can be difficult. In this guide we will try to lighten up the issue of concert microphones so that you can make an informed choice. Let's start by reviewing the microphone types.
Dynamic microphones are most commonly used on the stage. They have a very thin and light diaphragm, which moves under the influence of sound pressure. The diaphragm is in turn connected to a coil suspended in the magnetic field, which generates a small electrical voltage. These microphones are generally cheaper than capacitive microphones (although very high quality dynamic microphones can cost a lot), they are very durable and they can handle very high volume sound. Because of their construction , dynamic microphones are less sensitive to transients and do not register the highest frequencies as detailed as other types of microphones can do.
Condenser microphones are most commonly found in the studio. However, many of these types of microphones are also used now and in concert conditions. The condenser microphone is very simple construction compared to other types of microphones that do not have practically any moving parts. We will find a membrane that is a moving electrode and a second fixed electrode. They form a capacitor that is powered by an external source. When the acoustic pressure exerts an influence on the diaphragm, it vibrates slightly in accordance with the sound wave coming on it. Changes in the distance between the electrodes affect the capacity of the capacitor, and the resulting voltages are the output signal of the microphone
What is the resistance of the microphone?
If we look at the microphone specifications, we will find models described as "low impedance" and "high impedance" respectively low and high resistance. This is a value that tells the resistance of a microphone on a flowing signal. It is expressed in ohms. With regard to microphones we say that the resistance is low when it reaches below 600 ohms and high when its value exceeds 1000 ohms.
Microphones with high resistance can be built at a very low cost, but their sound quality drops sharply with the cable length. Hearable differences in signal quality start at about 5 meters of cable. Microphones with low resistance, in turn, can send signals over very long distances without much distortion. That is why most sound systems rely on them.
What is the directionality of the microphone?
Due to the type of construction, microphones react differently to sounds depending on their angle of incidence. Most microphones can be divided into two basic groups: omnidirectional and directional .
Cardioid characteristics are included in the group of directional microphones. It resembles a heart shape and shows where the microphone is most likely to "hear" the sound, and in which it suppresses. These types of microphones pick up the best sound from the front and dampen the sound from the back . This prevents conjugations and separates different sources of sound, such as vocals from the rest of the instruments. In general, the microphones used on the stage should have directional characteristics such as cardioid, supercardioid or hypercardioid.
Which microphone is right for me?
As you might guess, the choice of microphone that meets our expectations is influenced by several factors. We will probably use directional microphones for most applications because they separate well the sound source and prevent conjugation. The type of instrument that we will be milling, and the tone we want to get, determines whether we should use a dynamic or capacitive microphone.
Vocals
Some well-known vocalists use relatively cheap dynamic microphones such as the legendary Shure SM58 SE, instead of capacitive microphones. The reason is warmer and greasy sound, as well as more durability of such microphones. On the other hand, a subtle voice can gain quite a lot by using a condenser microphone that will give much more of its details. As to the directional characteristics we should take into account its two types: cardioid and hypercardioid.
Amplifier
A typical guitar amplifier has very similar sound characteristics to the human voice. In this case, we should use a dynamic microphone such as Shure SM57 LCE, Shure SM58 SE or Sennheiser MD 421 II. Dynamic microphones are able to handle very high sound pressure that is generated near the amplifier diaphragm.
Percussion
Mostly each drum kit component has a separate microphone. The use of a narrow-band microphone (cardioid or hypercardioid) on tom-tom can allows for isolation its from the rest of the set. The snare needs a microphone that can cope with very high sound pressure (SPL), so dynamic microphones will be here. The snare drum needs a microphone that can deal well with the lowest tones. Cymbals produce a lot of high frequencies, so we should use capacitive microphones with linear frequency characteristics . Manufacturers such as Shure, AKG and Sennheiser have special drum kits that should meet our requirements.
Summary
We hope this guide has brightened up the topic of microphones and their applications. The tips outlined here should serve as a starting point for your own experiments, because only in this way will we find our own sound and the best solutions.