DJ mixer

DJ mixer

From Wikipedia, the free encyclopedia
A DJ mixer is a type of audio mixing console used by disc jockeys. The key features that differentiate a DJ mixer from other types of audio mixers are the ability to redirect (cue) a non-playing source to headphones and the presence of a crossfader, which allows for an easier transition between two sources.
StructureA typical modern DJ mixer generally has between two and six stereo channels for connecting and mixing audio sources. Each channel usually has a phono input with RIAA equalization for turntables and one or two line level inputs for sources such as CD players. Controls for individual channels are arranged in vertical columns (channel strips), starting with a switch or a knob selecting between the inputs.
Below the input selector is a gain (or trim) control, used to match signal levels between channels. Next follows an equalizer section, used to fade parts of tracks in and out; a common basic technique is to kill the bass on one channel while mixing so the basslines of two tracks don't clash. Some more controls may follow, such as a balance knob, built-in sound effects and aux-sends for external effects units. Below there's normally a cue switch sending the signal to the headphones, letting the DJ to preview and beatmatch a track without sending it to the master output, but on some mixers there's a different way to select the cued source. Channel strip ends with a fader which sets the channel's signal volume in the final mix.
The signal may pass through a crossfader. On simple mixers there are normally two channels assigned opposite ends of the crossfader, sometimes with a button to reverse the crossfader's direction. More advanced mixers have assignable crossfaders in which each channel can be assigned to either end of the crossfader or to bypass the crossfader entirely. Many scratch mixers have a crossfader curve control that effectively changes the distance the crossfader needs to travel to open the channel fully, letting to shorten it to a millimetre or two, which is useful for speedy scratching (see turntablism).
Additionally, one or two microphone inputs may be present to accommodate MCs. These can be configured either as additional inputs to main channels or as special microphone channels which are similar in structure, but normally have fewer controls and are often monaural.
Most DJ mixers feature peak meters to aid matching levels between channels and monitor the signal for clipping. Usually there are peak meters for master mix and cued mix, though sometimes per-channel meters are present.
A DJ mixer has one or two headphone jack plugs and a headphone volume control. Headphones are normally used to monitor a cued channel, but on some mixers other variants are possible, such as split cue where cued channels are sent to the left headphone channel and master mix to the right, or a way to select between cued channels and master mix.
Normally there are two or more outputs for the master mix, used to send the signal to an amplifier or another mixer for the public address system, to a loudspeaker in the DJ booth for monitoring the mix, or to a tape recorder or a computer for recording. There may be one volume control for all outputs or separate controls for each outputs. Sometimes a recording output doesn't have a volume control.

Mixing Console

Mixing console

From Wikipedia, the free encyclopedia
In professional audio, a mixing console, digital mixing console, mixing desk (Brit.), or audio mixer, also called a sound board or soundboard, is an electronic device for combining (also called "mixing"), routing, and changing the level, tone, and/or dynamics of audio signals. A mixer can mix analog or digital signals, depending on the type of mixer. The modified signals (voltages or digital samples) are summed to produce the combined output signals.
Mixing consoles are used in many applications, including recording studios, public address systems, sound reinforcement systems, broadcasting, television, and film post-production. An example of a simple application would be to enable the signals that originated from two separate microphones (each being used by vocalists singing a duet, perhaps) to be heard through one set of speakers simultaneously. When used for live performances, the signal produced by the mixer will usually be sent directly to an amplifier, unless that particular mixer is “powered” or it is being connected to powered speakers.
StructureThe input strip is usually separated into these sections:
Input Jacks Input Section EQ Section AUX Section (Aux-sends) Fader / Bus On the Yamaha Console to the right, these sections are color coded.
Each signal that is input into the mixer has its own channel. Depending on the specific mixer, each channel is stereo or monaural. On most mixers, each channel has an XLR input, and many have RCA or quarter-inch Jack plug line inputs.
Below each input, there are usually several rotary controls (knobs, pots). The first is typically a trim or gain control. The inputs buffer the signal from the external device and this controls the amount of amplification or attenuation needed to bring the signal to a nominal level for processing. This stage is where most noise or interference is picked up, due to the high gains involved (around +50 dB, for a microphone). Balanced inputs and connectors, such as XLR or Tip-Ring-Sleeve (TRS) quarter-inch connectors, reduce interference problems.
There may be insert points after the buffer/gain stage, which send to and return from external processors which should only affect the signal of that particular channel. Insert points are most commonly used with effects that control a signal's amplitude, such as noise gates, expanders, and compressors.
The Aux sends send the incoming signal to external devices. Aux sends can either be pre-fade or post-fade, in that the level of a pre-fade send is set by the control, whereas post-fade depend on the position of the channel fader as well. Aux sends can be used to send the signal to an external processor such as a reverb, which can then be routed back through another channel or designated aux returns on the mixer. These will normally be post-fader. Pre-fade auxs provide a monitor mix to musicians onstage, this mix is thus independent of the main mix.
Mixing desk used for live performances.Further channel controls affect the equalization of the signal by separately attenuating or boosting a range of frequencies (e.g., bass, midrange, and treble frequencies). Most large mixing consoles (24 channels and larger) usually have sweep equalization in one or more bands of its parametric equalizer on each channel, where the frequency and affected bandwidth of equalization can be selected. Smaller mixing consoles have few or no equalization control. Many users recommend that the equalization be set so that if the speaker has a high frequency, elevate the lows and bring down the highs and vice versa for a low frequency speaker. This allows a little of amplication to be added to the general effects. However, this can distort the signal's EQ. Some mixers have a general equalization control (either graphic or parametric).
Each channel on a mixer has an audio taper pot, or potentiometer, controlled by a sliding volume control (fader), that allows adjustment of the level, or amplitude, of that channel in the final mix. A typical mixing console has many rows of these sliding volume controls. Each control adjusts only its respective channel (or one half of a stereo channel); therefore, it only affects the level of the signal from one microphone or other audio device. The signals are summed to create the main mix, or combined on a bus as a submix, a group of channels that are then added to get the final mix (for instance, many drum mics could be grouped into a bus, and then the proportion of drums in the final mix can be controlled with one bus fader).
There may also be insert points for a certain bus, or even the entire mix.
On the right hand of the console, there are typically one or two master controls that enable adjustment of the console's main mix output level. In recent years, with the demand for larger consoles, the main mix and submix controls have started to be placed in the center of the console. The idea behind this is that larger consoles often need two people to operate them, and that the first channels used are often the lower numbered channels. With the mains and subs in the middle, two people can easily control their own set of 16, 24, or 32 channels as well as easily reach the main controls. It is very rare to see this setup on boards with 24 or fewer channels.
Finally, there are usually one or more VU or peak meters to indicate the levels for each channel, or for the master outputs, and to indicate whether the console levels are overmodulating or clipping the signal. Most mixers have at least one additional output, besides the main mix. These are either individual bus outputs, or auxiliary outputs, used, for instance, to output a different mix to on-stage monitors. The operator can vary the mix (or levels of each channel) for each output.
As audio is heard in a logarithmic fashion (both amplitude and frequency), mixing console controls and displays are almost always in decibels, a logarithmic measurement system. This is also why special audio taper pots or circuits are needed. Since it is a relative measurement, and not a unit itself (like a percentage), the meters must be referenced to a nominal level. The "professional" nominal level is considered to be +4 dBu. The "consumer grade" level is ?10 dBV.
For convenience, some mixing console racks contain a patch bay or patch panel. These may be more useful for those not using a computer with several plugins on their software.
Most, but not all, audio mixers can
add external effects. use monaural signals to produce stereo sound by adjusting the position of each signal on the sound stage (pan and balance controls). provide phantom power (typically 48 volts) required by some microphones. create an audible tone via an oscillator, usually at 440 Hz, 1 kHz, or 2 kHz Some mixers can
add effects internally. interface with computers or other recording equipment (to control the mixer with computer presets, for instance). be powered by batteries.
Virtual Mixing consoles
Increasingly, the mixing process is performed on screen, using computer software. Often, tracks are built up individually or in groups, the whole composition only being playable after that stage in the process. This process requires an audio interface that converts analog audio into a digital format that can be used by the software. Pro Tools has offered a complete hardware and software package that has been the standard in the professional audio industry for many years, although other hardware manufacturers and software applications have made in-roads in recent years.
Mixing console manufacturersADT-Audio [1] Alesis [2] Alice Soundtech [3] Allen & Heath Amek [4] AMS Neve API Audio [5] Audient [6] Behringer Cadac [7] Calrec [8] Carvin A&I Crest Audio [9] D&R [10] DHD (audio) [11] DiGiCo [12] Digidesign [13] Dynacord [14] Elberg [15] Euphonix[16] EAW[17] Fairlight Harris Corporation Harrison Audio Consoles [18] InnovaSON [19] Inter-M [20] Jim Gamble Associates [21] Klotz Digital [22] Lawo [23] Mackie MCI Merging Technologies [24] Midas Consoles Neotek Peavey Phonic Corporation Radio Systems [25] Rane Corporation Renegade Labs [26] Salzbrenner Stagetec [27] [28] Samick Samson Technologies Shure SignVideo [29] Smart AV [30] Solid State Logic [31] Soundcraft [32] Stage-tec[33] Studer[34] Tapco Tascam Toft Audio Designs [35] Wheatstone Corporation [36] Yamaha Corporation