How to choose a microphone?
When selecting a microphone should be considered as the totality of his performance and recording conditions, and therefore give specific recommendations is difficult. However, the general rules for selecting the microphone is still there.
Omni-directional microphone can be used for recording singing and music in a highly anechoic room. Its the same should be used to transfer the general acoustic environment for a lot of microphones recording.
One-way directional microphone with a characteristic such as "cardioid" is desirable to use when writing in a room with lots of sound reflections. It is used in the case where the premises where the recording is carried out, penetrate background noise.
The microphone should be mounted to the back of the sound source of interference. This microphone is recommended for broad front placement of performers. This microphone is used in the unlikely circumstances mnogomikrofonnoy in amateur record for a clear separation of groups of performers, as well as the placement of the performer close to the microphone to reduce low-frequency distortion inherent in this case, undirected and bi-directional microphones.
Bi-directional microphone with a chart of "eight" should be used when recording in anechoic room when it is necessary to increase the relative level of signal status, as well as records of individual musical instruments and vocals to highlight the low frequencies in a close place, performers at the microphone. Use a microphone and volume. when you want to check out from the intended sources of noise. To orient the microphone of the zone of zero sensitivity to the noise source. Bi-directional microphone, oriented in the horizontal direction, it is useful to attenuate sound waves reflected from the floor, ceiling and side walls of the room. This allows us to apply an acoustic treatment of only two walls: a performer and in front of him.
In areas with hard parallel bounding surfaces (half-empty rooms with rough in for acoustic walls) may be the so-called standing waves. Standing waves are the characteristic oscillations in the cavity, which acts as a room with low acoustic attenuation. The frequencies of standing waves associated with the size of the room. Proper acoustic oscillations occur at frequencies at which a given room size is a multiple of half wavelengths. In a rectangular room, simultaneous existence of a set of standing waves of multiple frequencies (vibrational modes). The speed of sound is about 330 m / s, so that along the measurement space, which is, for example, 3 m, there will own acoustic oscillations with frequencies of 55, 110, 165 Hz, etc. The highest intensity of low-frequency modes are characterized by the most. With increasing frequency of natural oscillations of their amplitude decreases. Therefore, in a room having a great height, width and length, standing waves manifest themselves weaker, because the frequency of the most intense modes are below the lower limit of the frequency range of the microphone. Influence of standing waves is the distortion of the spectral composition of the recorded signal. At various points in the amplitude of the premises of their own resonant frequencies are different, so the tone of the same sound source depends ottochki microphone location. Particularly strong resonance properties of the room and the uneven frequency response of the microphone occur when a sound source generates a broadband signal that can excite vibrations on virtually any resonant frequencies. This is characteristic of some percussion instruments.
When recording with multiple microphones need to take care of their phasing: the signals from the microphones must not fall into the path entries in the opposite phase, since it can lead to mutual compensation of up to complete disappearance. Without appreciable distortion tone caused by interference between the direct and reflected signals, the microphone can be approximated by a reflecting surface at a distance, amounts to not less than 1-1.5 m
All efforts to improve the quality of records may be in vain if you do not comply with the rules of the obvious. One common error is the use of hand-in microphone. It can be justified only when the voice recording artist, is in motion. Manual use of the microphone requires a lot of experience. Watching on TV singers, perhaps juggling a microphone, be aware that in most cases you will not hear a "live" performance, and track. Most of the artists who have received at the microphone, do not know how to use it. The most common errors are the use of the microphone is too close, too harsh and unnecessary traffic to them, the motion of the fingers covering the microphone. In a pinch, you can live with for a single "live" performance, but not during the recording session.
The microphone must be securely with an elastic material at the front with a "crane" leg which also must be equipped with shock absorbers, preventing the impact of interference on the microphone (shock, vibration), propagating along the walls and floor of the room.
Signal cable should be shielded, connection must be reliable, next to the cable should not be located the sources of interference.