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.
Keyboard split
The presence in the device of the function of splitting the keyboard.
This function, as the name suggests, allows you to divide the keyboard into two parts, each of which will have a different timbre. Thus, on one device, you can play the part of two instruments at once (for example, add the sound of a string orchestra to the violin) or accompany the part of the instrument with various effects (siren, klaxon, thunder, etc.). Some models allow you to select the position of the border between the keyboard zones.
MIDI thru
The output to which the MIDI signals received at the MIDI In input are output (see the relevant paragraph). The key feature of this output is that the signals are output to it unchanged, regardless of the impact of the musician on the keyboard. In other words, if the MIDI Out input receives signals from both MIDI In and the keyboard itself, then MIDI Thru receives only signals from MIDI In.
MIDI Thru can come in handy when using the keyboard in large musical complexes where there are other sources of MIDI signal — in some cases it is convenient to use the keyboard as an intermediate link for these signals.
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.
