Rigidity
The hardness of the keys on a keyboard is the amount of resistance they provide when pressed.
—
Unweighted. Very low rigidity: the keys literally "fail" under the fingers. Found mostly in entry-level keyboards; this is due to the fact that unweighted mechanics are inexpensive, but the low pressure resistance makes it difficult to select the optimal pressure and control the dynamics of the sound.
— Semi-
weighted. Keyboards with medium resistance — not as high as on weighted keys, but noticeably higher than on unweighted ones. This option is considered optimal for active keyboards (see "Mechanics"): at a low cost, it gives quite good responsiveness and, with a minimum skill, allows you to accurately control the pressing force.
—
Weighted. Keyboards with high resistance, which is comparable to the resistance of classical piano keys. Note that high effort in this case is an advantage: it allows you to bring the response of the keyboard as close as possible to the response of a classical piano and makes it easier to control the pressure and dynamics of the sound. Actually, by definition, all hammer-action models are made weighted (see "Mechanics"), but among active keyboards this option is rare — due to complexity and high cost.
Pads
The number of
pads provided in the design of the keyboard.
Pads are auxiliary controls in the form of characteristic pads, usually square. The pads respond to touch, each of them can be tied to a specific sound or even a sequence of sounds. One of the most popular ways to use pads is to play drums or other rhythmic instruments.
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.
