Keys
The total number of keys on the keyboard.
The more keys provided in the design, the wider the instrument's own range, the more notes it can play without resorting to octave shift or transposition. On the other hand, this characteristic directly affects the dimensions and cost, and an extensive range is not required so often. Therefore,
88 -key instruments corresponding to a full-size classical piano keyboard are quite rare. But compact models with only
25 keys(2 octaves), on the contrary, are popular: for the purposes for which MIDI keyboards are used, this is often quite enough. Other common options are the
49 -key (4 octave) and
61 -key (5 octave) models; somewhat less common are
32 and
37 keys.
Transposition
The presence of the transposition function in the keyboard — switching the sound to a different key. When transposing, the pitch of all keys is simultaneously raised or lowered by a certain number of semitones. This function is useful in all cases when a melody learned in one key needs to be played in a different key — for example, if the original melody is too high or too low for the vocalist, if the external accompaniment differs in key, if you need to switch between keys during the song, and etc. In such situations, by transposing the sound, you can play a melody in a new key using the same familiar keys without relearning it.
Arpeggiator
The presence of an
arpeggiator in the keyboard.
The name of this function comes from "arpeggio" — a technique for playing chords, in which notes are not played all at once, but in turn. Accordingly, the arpeggiator is a function that allows you to play a taken chord in the arpeggio technique: the musician presses all the keys at once, and the keyboard plays them in turn. This effect can also be achieved manually, but in some cases the arpeggiator turns out to be more convenient: it plays notes at a clearly defined speed and interval, can accompany them with various effects, and provides other additional features. These features vary depending on the model, but some instruments allow you to create entire songs with the arpeggiator by simply pressing a sequence of chords.
Transport control
The presence in the keyboard of
the transport control function.
In this case, we are usually talking about support for the MIDI Machine Control standard, designed to control external recording and playback equipment. Such support actually turns the keyboard into an external remote control, allowing you to give commands from it to "Play", "Stop", "Pause", "Rewind" (forward and backward) and "Record". To do this, the design provides a separate panel with a set of appropriate buttons.
Faders
The number of
faders provided in the design of the keyboard.
A fader is a slider control. The simplest kind of such controls is the volume setting; if there is one fader in the design, most likely it is responsible for the volume. If there are more controls, other functions can be tied to them, respectively — in particular, changing the settings in the recording programme on the computer to which the keyboard is connected.
Regulators (encoders)
The number
of encoder controlsprovided in the design of the keyboard.
Such a knob looks like a rotary knob, with which you can control various functions of the device to which the keyboard is connected — for example, turn the virtual knobs in the programme for recording and sound processing. At the same time, we note that a full-fledged encoder is capable of rotating 360 ° and turning to any angle in any direction, however, keyboards can also contain knobs with a limited rotation sector — they can also be called encoders. None of these options has a clear advantage: in some cases, an unlimited turning sector is more convenient, in others, a limited one.
MIDI out
A specialized output for transmitting MIDI signals to an external device — a sequencer, a computer sound card (if there is a MIDI In input), etc.
MIDI signals are a kind of "digital notation": they tell which key was pressed, with what force and for how long, and also carry information about various additional parameters: timbre, tempo, key, etc. To convert such signals a "ready" sound requires an external sequencer (software or hardware).
Note that despite its specialized purpose, the
MIDI Out output is not mandatory for modern MIDI keyboards: MIDI signals can also be transmitted via other interfaces, such as USB or Bluetooth (see the relevant paragraphs). So it makes sense to specifically look for a keyboard with such a connector if you plan to connect it to equipment with a MIDI In input.
Display
The type
of display that the keyboard is equipped with.
Most modern MIDI keyboards have relatively simple monochrome (single colour) displays. Such screens are inexpensive, and their capabilities are sufficient for most cases. However, there are also models with colour screens — usually, such equipment is a sign of an advanced keyboard with an abundance of additional functions; for simpler devices, a colour display is overkill.
