Born from a purely communicative need, today the microphones play a functional and expressive role: singers, speakers or even acoustic and non-acoustic instruments thanks to the microphones have had the possibility to be amplified or recorded.
Since the microphone is a real transducer it responds to physical characteristics that influence its behavior (timbric and not only) and for this reason we can differentiate them for different constructive parameters.
The main parameter that influences a microphone is the type of transducer mounted.
What kind of transducer?
In the microphone we can find a transducer (capsule of the microphone) of the Dynamic type, Condenser or Ribbon.
The dynamic microphone is probably the most widespread and used for reasons of flexibility of use, strength and economy.
A Vocal microphone for live performances is 90% dynamic: the most famous example is undoubtedly the SHURE SM58 which is the most known cardioid dynamic in the world.
Frequent uses of the Dynamic microphone are the microphones for electric guitar amplifiers or the shooting of the individual pieces of a drum kit (in particular the case, snare, tom set, tympanum).
The condenser microphone, on the other hand, is a microphone that uses a pressure variation applied to the capsule to create an electrical signal.
The principle used is that of a capacitance with variable capacity depending on the position of the diaphragm under the effect of sound pressure.
To operate the circuitry in question, however, requires a power supply to polarize the armature of the capacitor in question that in our case will be a battery (if the microphone provides one) or the Phantom Power: it is a voltage (usually 48V) which is transferred to the microphone using the balanced XLR cable from a mixer or a specific power supply.
The result is that the condenser microphone is a more sensitive microphone with a more linear frequency response ensuring a more natural and detailed sound, especially at high frequencies.
For this reason the condenser microphone is used, for example, for the recording of acoustic voices or instruments (in the studio but also in live contexts).
We can then find variations based on the type of circuitry adopted (valve capacitor for example), based on the size of the capsule (we speak of large diaphragm or small diaphragm) or based on the number of capsules (some offer a double capsule, useful for some shooting techniques).
the tape microphone finally exploits the effect of the position variation of a tape positioned between 2 magnets due to the sound pressure of the applied source.
The characteristics of the ribbon microphone are undoubtedly the warm and soft tones offered and caused by a natural decay of the high frequencies very similar to those of the human ear.
Although the tape microphone is rarely used (also because of its delicate nature of the circuitry), it becomes undoubtedly indispensable where sound is sought for special needs: its applications go for example from mic for guitar amp to over head in a kit microphone microphone.
Each microphone then. regardless of the type of transducer, they can propose different polar diagrams. that is, with what "geometry" the transducer captures what surrounds it.
In fact, we find: Cardioids, supercardioids, hypercardioids, omnidirectional and figure-eight (in the case of a double capsule).
This influences the possible use, for example in the case of Live, where the cardioid due to its geometry does not pick up sounds or noises at 180 ° with respect to the capsule and this makes it preferable in the case of monitors positioned on the ground.
In the case of super or hyper cardioids, for example, we have a transducer no doubt more selective from the "front" side of the capsule itself, but also a sensitivity in counter-phase, 180 °: this imposes a positioning of the monitor in case of live frontal to the ground (in the case of a singer for example) to avoid feedback.