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.
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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.
Modulation controller
The presence of a
modulation controller in the keyboard.
This controller allows you to slightly change the volume of the sounding note. It is used mainly to achieve a characteristic "trembling" sound, which can be used both as an artistic technique and to imitate live performance on a particular instrument.
Sustain
The presence in the keyboard of its own sustain control — the extension of the extracted note. With sustain on, the note continues to sound (slowly decaying) even after the key has been released—similar to depressing the right pedal on a piano. Note that many keyboards allow the connection of pedals, including to control this function (see "Connected Pedals"), however, here it means its own controller, which allows you to turn sustain on and off using the keyboard itself, without additional equipment.
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.
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.
Connectable pedals
The maximum number of pedals that can be connected to the keyboard at the same time.
Pedals are used as additional controls to change various keyboard settings. The “classic of the genre” in this sense is the sustain pedal (see “Sustain”) — if the device has
one connector for pedals, then this will almost certainly be the input for just such a pedal. Keyboards are produced, where there
are 2 or more such inputs — in addition to sustain, you can connect pedals to them for other adjustments and effects (in particular, changing the volume).
Programming function
The ability to programme additional keyboard controls — buttons, pads, faders (see above), etc. — assigning them one or another function at your discretion. This feature allows you to optimally adjust the instrument to your needs and preferences. Note that the programming method can be different: most often you need to change the settings through a computer, but in some models this can also be done using built-in tools.
