Microphonology :
How To Get Your Mic Selection Right ?
A microphone may be great for picking up the sound of a flute but fatal for recording ambient sound in a football stadium . Therefore , the first thing is to know what we want it for and under what conditions . Based on that we will decide what directionality we need and what frequency response . Once defined , if we have several candidates and we do not decide , we can compare the sensitivity , and other data that we will see below :
Microphone noise Like any electronic element , the microphone produces noise inside it , so we must ensure that the noise generated is as low as possible compared to the audio signal that we are recording .
Signal to noise ratio ( S / R )
The signal-to-noise ratio actually represents the difference between the SPL level ( Sound Pressure level ) and the microphone ’ s own noise . The higher the SPL and the lower the noise , the better the signal-tonoise ratio , and vice versa . The higher the signal-to-noise ratio the better . It tells us what percentage of the SPL signal is above the background noise . If we have an SPL of 100 dB and a self-noise in the microphone of 30 dB , the signal-tonoise ratio will be 70 dB . For a 100 dB signal , a signal-to-noise ratio of 80 dB is very good and 70 dB is good .
Phantom power for microphones
Some microphones require power to function , specifically to keep the condenser charged . Some of these mics use batteries and others use phantom power . This supply is usually 48 volts and sometimes it is in the microphone itself and others in the device to which we are going to connect it . It is important to remember to connect it or not
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Pass filters
Some microphones incorporate a high-pass filter that eliminates ambient noise . If , for example , we have a filter with a frequency lower than 150Hz , it means that it will eliminate all bass noises and only allow frequencies from 150Hz to pass through .
WHAT MICROPHONE TO BUY ?
Shotgun microphone
They are long or narrow tube microphones that make them very directional super or hyper cardioid , to pick up sounds at long distances . Shotgun microphones are perfect for short films and documentaries .
Condenser microphone
They are called condensers because of the way they are constructed . They are high-fidelity and highly sensitive microphones , fragile and sensitive to humidity . This is why condenser microphones are often used in studios . These microphones need phantom power to keep the condenser charged .
Tie or Lavalier
They are usually omni-directional and may or may not be wireless . The lavalier microphones are ideal for interviews and podcasts as they manage to capture a clear and clean sound of the human voice .
Dynamic Microphones
Another type of microphone based on its construction is electrodynamic or dynamic . The mobile ones are the most common in live situations . They are low cost and very easy to use microphones . It is the idea that we all have of a microphone . They are very robust , very resistant and that is why they are perfect for outdoors and for live performances .
Electrodynamic tape
Electrodynamic microphones can be of two types : moving coil like the previous ones or ribbon . The ribbon ones work in a similar way to the dynamic ones , only that the element that vibrates inside is a very thin ribbon . They are very good two-way hi-fi mics but they are very heavy and expensive . They are typical of the 50 ’ s movies when two people sang in a duet .