A mixing console (“mixer”, or “mixing console”, from the English “mixing console” ) is an electronic device designed to mix audio signals: summing multiple sources into one or more outputs. Also with the help of a mixing console, signal routing is performed. The mixing console is used for sound recording , mixing and concert sound reinforcement. There are analog and digital mixing consoles, and each of these types has its own supporters and opponents, since both types have their own obvious advantages and disadvantages. Also, mixing consoles differ in the number of inputs and outputs. Professional concert and studio mixing consoles, as a rule, have at least 32 inputs, more than 6 Aux-buses, a powerful equalizer at the inputs, 4 or more subgroups, and also are equipped with high-precision and long-stroke faders . In turn, compact and budget mixers have a small number of channels, poorer equalizers , and are often devoid of faders (which are replaced by conventional potentiometers ).
There is a separate class of mixing consoles designed for DJ work . The main difference of the DJ-console is a smaller number of input channels (for example, one microphone and two stereo channels), the presence of a crossfader, with which the DJ smoothly reduces the signals of the input channels, as well as the presence of a block of special sound effects.
Mixing console structure
In general, any mixing console has an input section and an output section . The input section consists of a certain number of input channels (cells) - monaural and stereo. As a rule, the number of input channels on the consoles is a multiple of two. The input of each mono channel is usually decorated with two jacks: for a microphone ( XLR type) or a linear signal source ( TRS or RCA ).
Each input channel consists of several signal processing and routing units. The main ones are:
- Preamplifier with adjustable sensitivity (Gain or Trim), which allows you to optimally set the operating level of the input signal.
- The vast majority of mixing consoles have at the input a source of “phantom” power , which is necessary when using condenser microphones or some di-boxes.
- Multiband equalizer that allows you to adjust the frequency response of the signal. Professional mixing consoles are equipped with semi-parametric adjustment of strips, the number of which can reach six.
- The input signal routing unit for additional buses (Aux), which can be used for signal processing by an external (or built-in) effects processor, or for sending it to a separate monitor line. Depending on the configuration of the mixing console, Aux-buses can be from two to twelve. Any Aux-bus can work in two modes: Pre and Post - they determine the dependence of the signal level in the bus on the position of the volume fader . Thus, an individual mix (balance) of input sources can be created in the aux bus.
- Pan control, which determines the position of the signal in the stereo sound picture.
- The fader of the input volume, which determines its level in the overall balance of all channels.
The inputs of some mixing consoles are equipped with a “break point” (Insert), which is located after the preamp. This socket represents at the same time the input and output of this channel, which can be used to individually connect any signal processing device, for example, a compressor .
The output section of the mixing console is a system for managing and routing all outputs present on the console. This section may consist of:
- Fader level common (main) output.
- The subgroup cells, which are universal tires, allow you to combine input signals for a specific purpose and control such a group with one fader, or even send the group to a separate output. For example, you can combine all the signals of a drum kit into one subgroup.
- Aux-bus output level controls. In addition to the outputs for Aux-bus, many mixing consoles have Aux-inputs (so-called “return”), which, in fact, are additional inputs. Usually the send-return system is used to process the aux-bus signal by an external effects processor.
- Additional functions, such as: a common equalizer , a common stereo output to a mono signal, a matrix (an additional set of universal buses), blocks for listening to individual channels in headphones without interfering with the main balance, and much more.
The use and variety of mixing consoles
Mixers are used in all areas of sound amplification - recording studios, concert equipment, broadcasting equipment, radio stations, etc. There are mixing consoles with built-in power amplifiers (so-called “active mixers”) that are suitable for compact and mobile sound sets. Some professional studio and concert mixing consoles are equipped with electronic motor skills of all regulators, which allows them to be controlled from a computer, while the console itself remains analog, but their use is limited to a rather high cost.
Individual attention is given to digital mixing consoles, the main advantages of which are in more functional processing and routing units, the ability to save all settings in presets, and also in much more compact sizes. However, the digitization of the input signals and the reverse conversion of the digital signal to the analog signal led to the appearance of a large number of opponents of this technology. In addition, unlike traditional mixing consoles, where all the functions and controls are clear to any sound engineer, digital mixers take a certain amount of time to study them.
Another class of mixing consoles are the consoles for broadcasting studios of radio stations. These mixers, as a rule, are equipped with high-quality and ultra-reliable components and faders, as well as the so-called “telephone hybrids”, which are a cell designed to be coordinated with the telephone line .
Literature
- M.A. Sapozhkov. Acoustics. - M .: Radio and communication, 1989. - p. 182−185. - 336 seconds - 24 000 copies - ISBN 5-256-00187-6 .