3. Types of controls
The main task of a DJ, no matter which genre they work in, is selecting, playing and mixing pieces of music. And if this is done not on a notebook computer directly but using a MIDI controller, controls of various types are required. The following is intended to give an overview of these.
… mainly transmit start, stop, on and off commands, known as "toggles" or "triggers" in MIDI-speak. A toggle command changes a status from "on" to "off", as is the case in a light switch, for example. Trigger commands, on the other hand, release the same order on every activation of the switch, comparable to your car horn. In DJ software, toggle messages transmit commands such as play, pause and cue; they switch the pre-fade listening function on or off, set repetition loops or activate the addition of effects. Trigger messages, on the other hand, jump to hot cues or slicer positions, or start the playback of samples. Switches come in all sizes, colours, and shapes; they may be made from coloured hard palstic or semi-transparent illuminated solid rubber with status display. Some manufacturers' controllers even feature arcade buttons, reminiscent of the machines set up in gaming arcades in the 1908s.
…are the controller of choice when you are dealing with fading in and cross-fading, since they are eminently suitable for parameters which have to be controlled precisely. Generally, the longer the fader is, the more precisely your tuning will be. But a long fader is not always desirable, for example in cross-faders which are used to transition from track A to track B. Scratch DJs, furthermore, also attach importance to a curve controller or switch (rotary switch or step switch) to adapt the cross-fade characteristics and slew rate, respectively. If pressed, DJs will prefer a rapidly opening cross-fader which slides along the track as smoothly as a hot knife through butter, and which can be easily replaced once the wear and tear has become too much.
In order to achieve higher resolution, some manufacturers have eschewed the standard MIDI protocol (only 7 bit) in favour of solutions such as HiRes MIDI (14 bit!), to enable, for example adaptation precise down to a hundredth of a second in a tempo fader. If you are among those DJs who practice manual beat matching, you should focus on a high-resolution fader with a length of 80 - 100 millimetres, so that you can define the speed of a piece of music down to two hundredths of a second. This is important especially if you want your tracks to run in sync for an extended period of time. If you mix on a two-channel controller with four virtual desks, you should make sure that the pitch fader features LED indicators which show the direction of the value to be transported from the complementary deck on the same page.
Jog wheels and jog dials
Jog wheels are a controller's turntables, and are therefore naturally given similar tasks. If you want to use the turntables for scratching, they should be at least as large as your hands, which is also an advantage in adjusting the beat synchronicity of two tracks or if you want to drop in a kick drum. Creative types may "misappropriate" the jog wheels by using them for parameter runs of effects or in sampling. If they serve only for navigating and for fast-forwarding and rewinding through a track, a diameter of a few centimetres is sufficient. This smaller configuration is also known as a jog dial. Different DJ controllers feature hand wheels of different sizes and designs. There are some models which are as large as vinyl single (7"), coming with a real vinyl surface and powered by an engine to simulate the turntable or scratching feeling as realistically as possible. Other layouts may react capacitively to touch, or feature an integrated button which can be depressed. Simpler constructions simply translate the rotational movements (speed and direction).
The wheels likewise differ in their construction materials; metal designs are available, as are plastics or various combinations of the two. Sometimes, the surface is roughened or rubber-coated for improved grip, and there are indentations on the side for better finger control. The trend is going to flatter constructions at the moment, and the term in use for those is "low-profile jog wheels." If an individual feeling is especially important to you, or if you work in an environment characterised by strong vibration, you should also look for adjustable rotary resistance and maybe touch sensor sensitivity.
Rotary Controls and Encoders
Rotary controls are perfect to control parameters with defined minimum and maximum values. In some cases, such as the popular combination filters (left: high pass; right: low pass) or equalizers, a zero setting at the 12 o'clock position is desirable; in this position, the pot is neutral and does not influence the sound. Turning clockwise raises the frequency area, turning counterclockwise lowers it. This allows for easy visual checking. Effect pots, in contrast, which often cover a range from 0 to 100 do not necessarily require a click function at the 50 per cent mark, but the knob should be marked clearly anyway just to make it easier to check the current setting. Depending on their functions, rotary controls may come in very different sizes on the same device, and the smoother the resistance happens to be, the more delicate are the possibilities when mixing. The quality of the tops themselves is important, too - rubber-coated tops make for much better grip than smooth plastic ones do. If you are into tinkering with your equipment, you should also make a note of whether or not the manufacturer has put in bolted models and whether the shafts consist of metal or plastic, since the latter is liable to break when treated roughly (rentals, anyone?).
Rotary encoders are unlike pots in that they do not have a defined beginning and/or end point, and they are usually stepped. Thanks to the way they work, they are most suitable for controlling functions which require step-by-step movements in two directions. This makes them perfect tools to search your digital storage or to select tracks in your playlists. An integrated button may be included which allows the user to open folders in the side bar to navigate through complex directories or to serve for focus selection. Encoders are also your tool of choice to double or halve the length of loops, to set the smallest numerical values for example, BPM (128,65) or the clocking of effects (1/8, 1/4, etc.). A current encoder trend is integrating a touch sensor which tells the programme whether or not a controller has been touched and released. The software can then, as with a button, launch or interrupt a command or switch the view on the screen (for example, show the effect parameters if and when an effects control has been touched).
The introduction of expanded remix techniques in DJ software is what led to the inclusion of pad sections on DJ controllers. They often feature several layers of operation, they jump to hot cues, slice, chop, or start and stop the playback of samples. Usually, the pad section on a dual-deck controller consists of two rows of keys with four playing areas each, arranged above and below potentially present pots. Special controllers may even feature a 16x16 (or even larger) matrix. If you are a live remixer and only rarely use your turntables, you'll be best served with the pads located on the lower third of the controller which will give you the most immediate access. Scratch DJs, on the other hand, will prefer exposed faders and wheels, so putting an expansive key matrix at the top of the device is probably best. Depending on the price and quality of the hardware, pads may be velocity sensitive, i.e. they will also transmit the intensity of the touch. This is especially interesting if you wish to vary the volume of samples without having to use a fader. But if the pads are only intended to jump to hot cues or control loops, you can do without velocity. In some cases, you can even define the dynamic curves and the after-touch functions in the command centre setup menu.
Touch pads and Ribbons
One-dimensional touch strips allow navigation, spool in tracks, select tracks, serve as fade/pitch substitutes or are split up into functional areas to fire off samples or loops. If they are to substitute for jog wheels, they can also take over the pitch bending, i.e. speeding up or slowing down the virtual turntable. Two-dimensional x/y pads, on the other hand, usually serve to replace the computer mouse or allow for the control of two elements in the coordinate cross.
Level displays support the DJ in matching the volumes of several sources, and on the dance floor, of course! If various sources and decks are used, level displays in the channels may already give a visual feedback on the channel's volume even before the fader has been opened. The master display, meanwhile, indicates the output volume. Here, the traffic light system has become the norm over the years, i.e. green light all the way down to zero dB, and a yellow warning light before you enter the red overload zone. Some entry-level controllers do without level displays entirely, whereas they are an absolute must in a device that should meet semi or fully professional requirements.
DJ work stations with CD drives or USB slots feature LCDs which mainly serve to select tracks and show information on the tracks and run times. But with MIDI controllers, too, a new trend can be observed: the integration of large full-colour displays allow for the graphic representation of all data directly on the controller. This renders computer screens unnecessary for large parts of a mixing session, and it emphasizes the performance even more. DJs may be able to put their notebooks aside, which gives them a full view of their audience. Information on the track in playback, such as bpm, time remaining, pitch, sync, or key, as well as an overview of the wave form or sectional views to determine the breaks or visualise the cue points. You can select effects or read values and maybe the most important thing: you can search your music libraries and select tracks, which is what it's all about, after all!
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