The Electrical Era so much to cover! So, we won’t cover it all.
Instead, we can cover the microphone- whose sonic capabilities dwarfed the acoustic era. If you are reading this you are likely working in your own, budget, home studio. I suggest we cover the most important microphones for such individuals! Dynamic and condenser microphones.
First, what is a microphone?
A microphone is a transducer (or has a transducer.) A speaker is a transducer. A thermometer is a transducer. Just be aware that transducers live outside the realm of microphones as well! Transducers take one form of energy and converts it into another. In this case, physical force of sound waves into electricity. Microphones take sound pressure variations and turn them into voltage variations. The element type of a microphone will decide how this process is done.
Dynamic Moving Coil Microphones
Favored on stage for their rugged build and tough diaphragms. I got ahead of myself, unless you were already referencing the picture above. A dynamic microphone consists of a diaphragm, magnet, coil and wires the carry the electrical current it creates. The diaphragm will usually be made out of rubber or plastic and be mounted on the front of the element. Normally there is only one diaphragm, but multi-diaphragm dynamic mics are rare. The physical force of sound waves that hit the diaphragm cause the coil to move into the magnet’s magnetic field. When this happens, a current is created which is why a dynamic microphone doesn’t need external power to transduce physical energy into electricity. Pretty neat. The vibrations from the coil create the electrical signal the wires will then output to your desired source.
Dynamic microphones are great, but have a generally low sensitivity. Meaning, you aren’t going to get the greatest clarity out of this- especially being quiet in an apartment studio. Often this type of microphone is made to perform a relatively specific function, or designed to be better at replicating certain frequencies. Dynamic moving coils are great at handling loud sound sources without distorting, unlike other microphones.
Condenser Microphone
The condenser microphone is far more sensitive and has greater clarity than the dynamic. If you look at the reference picture above, you may notice a few differences in this microphone. A condenser will consist of a front plate, back plate, power source and a way to output the audio signal. The front plate is the diaphragm on this microphone and it will be made of a thin pliable metal. The second plate behind it is a mounted motionless plate. Power is normally applied via Phantom Power (+48V) from an interface or console, but in some cases batteries supply this power. The power source creates an electrical field between the two plates, where once again sound waves vibrate this diaphragm to create an output signal. If the sound pressure becomes to great the diaphragm can hit the back plate and damage the element.
The great advantage to us as home studio junkies- is the sensitivity! Supplying the +48V power allows for an amplified signal for our soft-spoken vocals and acoustic guitars can still be captured with great fidelity. Without annoying the neighbors. It’s also to keep in mind that a condenser, unless it was specifically designed to handle high SPL levels- it’s safe to assume they won’t. It’s very easy to damage the element when overloaded. Phantom Power also poses one of the biggest problems without careful thought or acoustic treatment. The noise in and outside of your room can be amplified as well. We want to keep that noise out of our mixes.
It’s amazing to see how capturing sound has developed. From the acoustic era frequency ranges were greatly limited and the introduction of the microphone added a much larger bandwidth to the audio engineer’s arsenal. In the early electric era frequency ranges were still somewhat limited, but today we can easily capture all frequencies within our human ability to hear them! During the electric era artists were still limited by the use of only one microphone. Artist placement had to be meticulous- and then the magnetic era came with multitrack recording and began changing everything.