The principle of work with the equalizer and its application
When working with the equalizer, it is very important to understand that amplification of a frequency band leads to an increase in the overall level of the audio signal, and excessive amplification of the bands can often lead to distortion of the audio signal. In this regard, the weakening of the “unnecessary” frequencies often gives a better result than the amplification of the “necessary”. Therefore, the equalizer should be used very carefully and not used if there is no obvious need for it.
Equalizers have a wide range of applications. Their main purpose is to obtain an adequate (linear) sounding of the source material, the frequency response of which can be distorted due to shortcomings of acoustic systems, inter-unit processing devices, room parameters, etc.
Often equalizers are used in the lines of stage monitors, the main problem of which is the occurrence of the “feedback” effect. In this case, the sound engineer uses a multi-band graphic equalizer to search for the resonant frequency and its attenuation. In addition, using the equalizer, you can limit the frequency range of sound reproduction. However, not all experts use graphic equalizers to eliminate feedback, since there are special devices for this – digital automatic feedback suppressors, which, in essence, are a parametric equalizer with automatic selection of the resonant frequency, and their filters have a very high Q factor.
When recording or performing, many musicians use various equalizers to obtain the unique sound of their instruments, as well as special effects associated with the bright highlighting of specific frequency bands. For example, removing all low and high frequencies with an equalizer, leaving only the middle range, you can get the effect of the “old radio”. Almost all DJs during the sets actively use the equalizers on the mixing consoles, again to create certain effects.
Another fundamental application of the equalizer is the frequency correction of sound reproduction of stationary sound amplification systems depending on the acoustic parameters of the room. The frequency response of sound is influenced by many factors: the size and shape of the room, wall coverings, the number of spectators in the room and much more – all this can greatly change the frequency response of the reproduced material. In this case, specialists use three main components: a high-precision measuring microphone, a spectrum analyzer and an equalizer. All this allows him to find out which frequencies “disappear” in this room and which are allocated, and in accordance with this, make a correction.
In recording studios, equalizers in the form of separate devices are used infrequently. This is due to the fact that modern studios are equipped with equipment that practically does not distort the frequency response of the recorded material. However, with digital mixing and mastering, virtually all tracks “pass through” the software equalizer, but, as a rule, in order to remove or weaken unnecessary frequencies that can interfere with the purity of the resulting mix. This is especially true for the voice (vocals), which has a fairly narrow frequency range, as well as some disadvantages that may be associated with articulation and manner of performance.
Mixing instruments is a real art, and the sound engineer has to turn to the equalizer more than once before he finds the sound he needs. Many instruments have such a powerful and rich sound that it is almost impossible to transmit a close-set microphone. This is where the equalizer comes to the rescue, the main purpose of which is to convey to us this sound in its most natural form.
The transparency of the sound of many instruments can be significantly increased by emphasizing their harmonics. Our ear hears them even in the lowest sounds with a seemingly narrow spectrum. Drums are one of such instruments, the sound brightness of which can be significantly increased by simply reducing the gain in the lower part of the spectrum, thereby emphasizing the harmonics existing in the sound. Here are a few thoughts about what exactly some of the frequencies do with sound and how our ears feel.